From: visa Date: Thu, 20 Apr 2017 12:59:36 +0000 (+0000) Subject: Add a port of witness(4) lock validation tool from FreeBSD. X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=a7c28c925d52c08052dec29fb536c4a5cda09e35;p=openbsd Add a port of witness(4) lock validation tool from FreeBSD. Go-ahead from kettenis@, guenther@, deraadt@ --- diff --git a/sys/conf/files b/sys/conf/files index 988da36b099..7942262486a 100644 --- a/sys/conf/files +++ b/sys/conf/files @@ -1,4 +1,4 @@ -# $OpenBSD: files,v 1.639 2017/02/08 05:09:25 guenther Exp $ +# $OpenBSD: files,v 1.640 2017/04/20 12:59:36 visa Exp $ # $NetBSD: files,v 1.87 1996/05/19 17:17:50 jonathan Exp $ # @(#)files.newconf 7.5 (Berkeley) 5/10/93 @@ -698,6 +698,7 @@ file kern/dma_alloc.c file kern/subr_prf.c file kern/subr_prof.c file kern/subr_userconf.c boot_config +file kern/subr_witness.c witness file kern/subr_xxx.c file kern/sys_generic.c file kern/sys_pipe.c diff --git a/sys/ddb/db_command.c b/sys/ddb/db_command.c index 0796df039bb..bece0279d5d 100644 --- a/sys/ddb/db_command.c +++ b/sys/ddb/db_command.c @@ -1,4 +1,4 @@ -/* $OpenBSD: db_command.c,v 1.71 2016/04/19 12:23:25 mpi Exp $ */ +/* $OpenBSD: db_command.c,v 1.72 2017/04/20 12:59:36 visa Exp $ */ /* $NetBSD: db_command.c,v 1.20 1996/03/30 22:30:05 christos Exp $ */ /* @@ -112,6 +112,9 @@ void db_struct_offset_cmd(db_expr_t, int, db_expr_t, char *); void db_struct_layout_cmd(db_expr_t, int, db_expr_t, char *); void db_show_regs(db_expr_t, boolean_t, db_expr_t, char *); void db_write_cmd(db_expr_t, boolean_t, db_expr_t, char *); +void db_witness_display(db_expr_t, int, db_expr_t, char *); +void db_witness_list(db_expr_t, int, db_expr_t, char *); +void db_witness_list_all(db_expr_t, int, db_expr_t, char *); /* @@ -552,6 +555,9 @@ struct db_command db_show_all_cmds[] = { #ifdef NFSCLIENT { "nfsreqs", db_show_all_nfsreqs, 0, NULL }, { "nfsnodes", db_show_all_nfsnodes, 0, NULL }, +#endif +#ifdef WITNESS + { "locks", db_witness_list_all, 0, NULL }, #endif { NULL, NULL, 0, NULL } }; @@ -562,6 +568,9 @@ struct db_command db_show_cmds[] = { { "breaks", db_listbreak_cmd, 0, NULL }, { "buf", db_buf_print_cmd, 0, NULL }, { "extents", db_extent_print_cmd, 0, NULL }, +#ifdef WITNESS + { "locks", db_witness_list, 0, NULL }, +#endif { "malloc", db_malloc_print_cmd, 0, NULL }, { "map", db_map_print_cmd, 0, NULL }, { "mbuf", db_mbuf_print_cmd, 0, NULL }, @@ -586,6 +595,9 @@ struct db_command db_show_cmds[] = { { "uvmexp", db_uvmexp_print_cmd, 0, NULL }, { "vnode", db_vnode_print_cmd, 0, NULL }, { "watches", db_listwatch_cmd, 0, NULL }, +#ifdef WITNESS + { "witness", db_witness_display, 0, NULL }, +#endif { NULL, NULL, 0, NULL } }; diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c index b231ccbafb8..9b6291d4352 100644 --- a/sys/kern/init_main.c +++ b/sys/kern/init_main.c @@ -1,4 +1,4 @@ -/* $OpenBSD: init_main.c,v 1.267 2017/03/06 10:48:16 mpi Exp $ */ +/* $OpenBSD: init_main.c,v 1.268 2017/04/20 12:59:36 visa Exp $ */ /* $NetBSD: init_main.c,v 1.84.4.1 1996/06/02 09:08:06 mrg Exp $ */ /* @@ -75,6 +75,7 @@ #include #include #include +#include #include #include @@ -216,6 +217,8 @@ main(void *framep) printf("%s\n", copyright); + WITNESS_INITIALIZE(); + KERNEL_LOCK_INIT(); SCHED_LOCK_INIT(); diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c index 050369baa4f..cd0e6df2cd0 100644 --- a/sys/kern/kern_exit.c +++ b/sys/kern/kern_exit.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_exit.c,v 1.159 2017/02/08 20:58:30 guenther Exp $ */ +/* $OpenBSD: kern_exit.c,v 1.160 2017/04/20 12:59:36 visa Exp $ */ /* $NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $ */ /* @@ -64,6 +64,7 @@ #ifdef SYSVSEM #include #endif +#include #include #include @@ -429,6 +430,8 @@ reaper(void) LIST_REMOVE(p, p_hash); mtx_leave(&deadproc_mutex); + WITNESS_THREAD_EXIT(p); + KERNEL_LOCK(); /* diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c index 0cb6b56839d..edaa6b0a977 100644 --- a/sys/kern/kern_fork.c +++ b/sys/kern/kern_fork.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_fork.c,v 1.196 2017/04/13 03:52:25 guenther Exp $ */ +/* $OpenBSD: kern_fork.c,v 1.197 2017/04/20 12:59:36 visa Exp $ */ /* $NetBSD: kern_fork.c,v 1.29 1996/02/09 18:59:34 christos Exp $ */ /* @@ -169,6 +169,10 @@ thread_new(struct proc *parent, vaddr_t uaddr) */ scheduler_fork_hook(parent, p); +#ifdef WITNESS + p->p_sleeplocks = NULL; +#endif + return p; } diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c index de0e1cb5a0f..9d80487026d 100644 --- a/sys/kern/kern_sig.c +++ b/sys/kern/kern_sig.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_sig.c,v 1.210 2017/04/14 15:11:31 bluhm Exp $ */ +/* $OpenBSD: kern_sig.c,v 1.211 2017/04/20 12:59:36 visa Exp $ */ /* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */ /* @@ -63,6 +63,7 @@ #include #include #include +#include #include #include @@ -1846,6 +1847,8 @@ userret(struct proc *p) KERNEL_UNLOCK(); } + WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); + p->p_cpu->ci_schedstate.spc_curpriority = p->p_priority = p->p_usrpri; } diff --git a/sys/kern/subr_witness.c b/sys/kern/subr_witness.c new file mode 100644 index 00000000000..5129871ff8c --- /dev/null +++ b/sys/kern/subr_witness.c @@ -0,0 +1,2525 @@ +/* $OpenBSD: subr_witness.c,v 1.1 2017/04/20 12:59:36 visa Exp $ */ + +/*- + * Copyright (c) 2008 Isilon Systems, Inc. + * Copyright (c) 2008 Ilya Maykov + * Copyright (c) 1998 Berkeley Software Design, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Berkeley Software Design Inc's name may not be used to endorse or + * promote products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * from BSDI $Id: subr_witness.c,v 1.1 2017/04/20 12:59:36 visa Exp $ + * and BSDI $Id: subr_witness.c,v 1.1 2017/04/20 12:59:36 visa Exp $ + */ + +/* + * Implementation of the `witness' lock verifier. Originally implemented for + * mutexes in BSD/OS. Extended to handle generic lock objects and lock + * classes in FreeBSD. + */ + +/* + * Main Entry: witness + * Pronunciation: 'wit-n&s + * Function: noun + * Etymology: Middle English witnesse, from Old English witnes knowledge, + * testimony, witness, from 2wit + * Date: before 12th century + * 1 : attestation of a fact or event : TESTIMONY + * 2 : one that gives evidence; specifically : one who testifies in + * a cause or before a judicial tribunal + * 3 : one asked to be present at a transaction so as to be able to + * testify to its having taken place + * 4 : one who has personal knowledge of something + * 5 a : something serving as evidence or proof : SIGN + * b : public affirmation by word or example of usually + * religious faith or conviction + * 6 capitalized : a member of the Jehovah's Witnesses + */ + +/* + * Special rules concerning Giant and lock orders: + * + * 1) Giant must be acquired before any other mutexes. Stated another way, + * no other mutex may be held when Giant is acquired. + * + * 2) Giant must be released when blocking on a sleepable lock. + * + * This rule is less obvious, but is a result of Giant providing the same + * semantics as spl(). Basically, when a thread sleeps, it must release + * Giant. When a thread blocks on a sleepable lock, it sleeps. Hence rule + * 2). + * + * 3) Giant may be acquired before or after sleepable locks. + * + * This rule is also not quite as obvious. Giant may be acquired after + * a sleepable lock because it is a non-sleepable lock and non-sleepable + * locks may always be acquired while holding a sleepable lock. The second + * case, Giant before a sleepable lock, follows from rule 2) above. Suppose + * you have two threads T1 and T2 and a sleepable lock X. Suppose that T1 + * acquires X and blocks on Giant. Then suppose that T2 acquires Giant and + * blocks on X. When T2 blocks on X, T2 will release Giant allowing T1 to + * execute. Thus, acquiring Giant both before and after a sleepable lock + * will not result in a lock order reversal. + */ + +#if 0 +__FBSDID("$FreeBSD: head/sys/kern/subr_witness.c 313261 2017-02-05 02:27:04Z markj $"); +#endif + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include /* uvm_pageboot_alloc */ + +#ifndef DDB +#error "DDB is required for WITNESS" +#endif + +#include + +#include +#include +#include + +/* XXX */ +#define CTR1(...) +#define CTR3(...) +#define CTR4(...) + +#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */ +#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */ +#define LI_NORELEASE 0x00020000 /* Lock not allowed to be released. */ + +#ifndef WITNESS_COUNT +#define WITNESS_COUNT 1536 +#endif +#define WITNESS_HASH_SIZE 251 /* Prime, gives load factor < 2 */ +#define WITNESS_PENDLIST (1024 + MAXCPUS) + +/* Allocate 256 KB of stack data space */ +#define WITNESS_LO_DATA_COUNT 2048 + +/* Prime, gives load factor of ~2 at full load */ +#define WITNESS_LO_HASH_SIZE 1021 + +/* + * XXX: This is somewhat bogus, as we assume here that at most 2048 threads + * will hold LOCK_NCHILDREN locks. We handle failure ok, and we should + * probably be safe for the most part, but it's still a SWAG. + */ +#define LOCK_NCHILDREN 5 +#define LOCK_CHILDCOUNT 2048 + +#define FULLGRAPH_SBUF_SIZE 512 + +/* + * These flags go in the witness relationship matrix and describe the + * relationship between any two struct witness objects. + */ +#define WITNESS_UNRELATED 0x00 /* No lock order relation. */ +#define WITNESS_PARENT 0x01 /* Parent, aka direct ancestor. */ +#define WITNESS_ANCESTOR 0x02 /* Direct or indirect ancestor. */ +#define WITNESS_CHILD 0x04 /* Child, aka direct descendant. */ +#define WITNESS_DESCENDANT 0x08 /* Direct or indirect descendant. */ +#define WITNESS_ANCESTOR_MASK (WITNESS_PARENT | WITNESS_ANCESTOR) +#define WITNESS_DESCENDANT_MASK (WITNESS_CHILD | WITNESS_DESCENDANT) +#define WITNESS_RELATED_MASK \ + (WITNESS_ANCESTOR_MASK | WITNESS_DESCENDANT_MASK) +#define WITNESS_REVERSAL 0x10 /* A lock order reversal has been + * observed. */ +#define WITNESS_RESERVED1 0x20 /* Unused flag, reserved. */ +#define WITNESS_RESERVED2 0x40 /* Unused flag, reserved. */ +#define WITNESS_LOCK_ORDER_KNOWN 0x80 /* This lock order is known. */ + +/* Descendant to ancestor flags */ +#define WITNESS_DTOA(x) (((x) & WITNESS_RELATED_MASK) >> 2) + +/* Ancestor to descendant flags */ +#define WITNESS_ATOD(x) (((x) & WITNESS_RELATED_MASK) << 2) + +#define WITNESS_INDEX_ASSERT(i) \ + KASSERT((i) > 0 && (i) <= w_max_used_index && (i) < witness_count) + +/* + * Lock classes. Each lock has a class which describes characteristics + * common to all types of locks of a given class. + * + * Spin locks in general must always protect against preemption, as it is + * an error to perform any type of context switch while holding a spin lock. + * Also, for an individual lock to be recursable, its class must allow + * recursion and the lock itself must explicitly allow recursion. + */ + +struct lock_class { + const char *lc_name; + u_int lc_flags; +}; + +#define LC_SLEEPLOCK 0x00000001 /* Sleep lock. */ +#define LC_SPINLOCK 0x00000002 /* Spin lock. */ +#define LC_SLEEPABLE 0x00000004 /* Sleeping allowed with this lock. */ +#define LC_RECURSABLE 0x00000008 /* Locks of this type may recurse. */ +#define LC_UPGRADABLE 0x00000010 /* Upgrades and downgrades permitted. */ + +/* + * Lock instances. A lock instance is the data associated with a lock while + * it is held by witness. For example, a lock instance will hold the + * recursion count of a lock. Lock instances are held in lists. Spin locks + * are held in a per-cpu list while sleep locks are held in per-thread list. + */ +struct lock_instance { + struct lock_object *li_lock; + const char *li_file; + int li_line; + u_int li_flags; +}; + +/* + * A simple list type used to build the list of locks held by a thread + * or CPU. We can't simply embed the list in struct lock_object since a + * lock may be held by more than one thread if it is a shared lock. Locks + * are added to the head of the list, so we fill up each list entry from + * "the back" logically. To ease some of the arithmetic, we actually fill + * in each list entry the normal way (children[0] then children[1], etc.) but + * when we traverse the list we read children[count-1] as the first entry + * down to children[0] as the final entry. + */ +struct lock_list_entry { + struct lock_list_entry *ll_next; + struct lock_instance ll_children[LOCK_NCHILDREN]; + int ll_count; +}; + +/* + * The main witness structure. One of these per named lock type in the system + * (for example, "vnode interlock"). + */ +struct witness { + struct lock_type *w_type; + const char *w_subtype; + uint32_t w_index; /* Index in the relationship matrix */ + struct lock_class *w_class; + SIMPLEQ_ENTRY(witness) w_list; /* List of all witnesses. */ + SIMPLEQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */ + struct witness *w_hash_next; /* Linked list in hash buckets. */ + const char *w_file; /* File where last acquired */ + uint32_t w_line; /* Line where last acquired */ + uint16_t w_num_ancestors; /* direct/indirect + * ancestor count */ + uint16_t w_num_descendants; /* direct/indirect + * descendant count */ + int16_t w_ddb_level; + unsigned w_displayed:1; + unsigned w_reversed:1; +}; + +SIMPLEQ_HEAD(witness_list, witness); + +/* + * The witness hash table. Keys are witness names (const char *), elements are + * witness objects (struct witness *). + */ +struct witness_hash { + struct witness *wh_array[WITNESS_HASH_SIZE]; + uint32_t wh_size; + uint32_t wh_count; +}; + +/* + * Key type for the lock order data hash table. + */ +struct witness_lock_order_key { + uint16_t from; + uint16_t to; +}; + +struct witness_lock_order_data { + struct db_stack_trace wlod_stack; + struct witness_lock_order_key wlod_key; + struct witness_lock_order_data *wlod_next; +}; + +/* + * The witness lock order data hash table. Keys are witness index tuples + * (struct witness_lock_order_key), elements are lock order data objects + * (struct witness_lock_order_data). + */ +struct witness_lock_order_hash { + struct witness_lock_order_data *wloh_array[WITNESS_LO_HASH_SIZE]; + u_int wloh_size; + u_int wloh_count; +}; + +struct witness_pendhelp { + struct lock_type *wh_type; + struct lock_object *wh_lock; +}; + +struct witness_cpu { + struct lock_list_entry *wc_spinlocks; +}; + +struct witness_cpu witness_cpu[MAXCPUS]; + +/* + * Returns 0 if one of the locks is a spin lock and the other is not. + * Returns 1 otherwise. + */ +static __inline int +witness_lock_type_equal(struct witness *w1, struct witness *w2) +{ + + return ((w1->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) == + (w2->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))); +} + +static __inline int +witness_lock_order_key_equal(const struct witness_lock_order_key *a, + const struct witness_lock_order_key *b) +{ + + return (a->from == b->from && a->to == b->to); +} + +static int _isitmyx(struct witness *w1, struct witness *w2, int rmask, + const char *fname); +static void adopt(struct witness *parent, struct witness *child); +static struct witness *enroll(struct lock_type *, const char *, + struct lock_class *); +static struct lock_instance *find_instance(struct lock_list_entry *list, + const struct lock_object *lock); +static int isitmychild(struct witness *parent, struct witness *child); +static int isitmydescendant(struct witness *parent, struct witness *child); +static void itismychild(struct witness *parent, struct witness *child); +#ifdef DDB +static void db_witness_add_fullgraph(struct witness *parent); +static void witness_ddb_compute_levels(void); +static void witness_ddb_display(int(*)(const char *fmt, ...)); +static void witness_ddb_display_descendants(int(*)(const char *fmt, ...), + struct witness *, int indent); +static void witness_ddb_display_list(int(*prnt)(const char *fmt, ...), + struct witness_list *list); +static void witness_ddb_level_descendants(struct witness *parent, int l); +static void witness_ddb_list(struct proc *td); +#endif +static void witness_debugger(int cond, const char *msg); +static void witness_free(struct witness *m); +static struct witness *witness_get(void); +static uint32_t witness_hash_djb2(const uint8_t *key, uint32_t size); +static struct witness *witness_hash_get(struct lock_type *, const char *); +static void witness_hash_put(struct witness *w); +static void witness_init_hash_tables(void); +static void witness_increment_graph_generation(void); +static int witness_list_locks(struct lock_list_entry **, + int (*)(const char *, ...)); +static void witness_lock_list_free(struct lock_list_entry *lle); +static struct lock_list_entry *witness_lock_list_get(void); +static int witness_lock_order_add(struct witness *parent, + struct witness *child); +static int witness_lock_order_check(struct witness *parent, + struct witness *child); +static struct witness_lock_order_data *witness_lock_order_get( + struct witness *parent, + struct witness *child); +static void witness_list_lock(struct lock_instance *instance, + int (*prnt)(const char *fmt, ...)); +static int witness_output(const char *fmt, ...) + __attribute__((__format__(__kprintf__, 1, 2))); +static int witness_voutput(const char *fmt, va_list ap) + __attribute__((__format__(__kprintf__, 1, 0))); +static void witness_setflag(struct lock_object *lock, int flag, int set); + +/* + * If set to 0, lock order checking is disabled. If set to -1, + * witness is completely disabled. Otherwise witness performs full + * lock order checking for all locks. At runtime, lock order checking + * may be toggled. However, witness cannot be reenabled once it is + * completely disabled. + */ +static int witness_watch = 1; + +#ifdef WITNESS_SKIPSPIN +int witness_skipspin = 1; +#else +int witness_skipspin = 0; +#endif + +int witness_count = WITNESS_COUNT; + +/* + * Output channel for witness messages. By default we print to the console. + */ +enum witness_channel { + WITNESS_CONSOLE, + WITNESS_LOG, + WITNESS_NONE, +}; + +static enum witness_channel witness_channel = WITNESS_CONSOLE; + +static struct mutex w_mtx; + +/* w_list */ +static struct witness_list w_free = SIMPLEQ_HEAD_INITIALIZER(w_free); +static struct witness_list w_all = SIMPLEQ_HEAD_INITIALIZER(w_all); + +/* w_typelist */ +static struct witness_list w_spin = SIMPLEQ_HEAD_INITIALIZER(w_spin); +static struct witness_list w_sleep = SIMPLEQ_HEAD_INITIALIZER(w_sleep); + +/* lock list */ +static struct lock_list_entry *w_lock_list_free = NULL; +static struct witness_pendhelp pending_locks[WITNESS_PENDLIST]; +static u_int pending_cnt; + +static int w_free_cnt, w_spin_cnt, w_sleep_cnt; + +static struct witness *w_data; +static uint8_t **w_rmatrix; +static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; +static struct witness_hash w_hash; /* The witness hash table. */ + +/* The lock order data hash */ +static struct witness_lock_order_data w_lodata[WITNESS_LO_DATA_COUNT]; +static struct witness_lock_order_data *w_lofree = NULL; +static struct witness_lock_order_hash w_lohash; +static int w_max_used_index = 0; +static unsigned int w_generation = 0; +static const char w_notrunning[] = "Witness not running\n"; +static const char w_stillcold[] = "Witness is still cold\n"; + +static struct lock_class lock_class_kernel_lock = { + .lc_name = "kernel_lock", + .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE | LC_SLEEPABLE +}; + +static struct lock_class lock_class_sched_lock = { + .lc_name = "sched_lock", + .lc_flags = LC_SPINLOCK | LC_RECURSABLE +}; + +static struct lock_class lock_class_mutex = { + .lc_name = "mutex", + .lc_flags = LC_SPINLOCK +}; + +static struct lock_class lock_class_rwlock = { + .lc_name = "rwlock", + .lc_flags = LC_SLEEPLOCK | LC_SLEEPABLE | LC_UPGRADABLE +}; + +static struct lock_class lock_class_rrwlock = { + .lc_name = "rrwlock", + .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE | LC_SLEEPABLE | + LC_UPGRADABLE +}; + +static struct lock_class *lock_classes[] = { + &lock_class_kernel_lock, + &lock_class_sched_lock, + &lock_class_mutex, + &lock_class_rwlock, + &lock_class_rrwlock, +}; + +/* + * This global is set to 0 once it becomes safe to use the witness code. + */ +static int witness_cold = 1; + +/* + * This global is set to 1 once the static lock orders have been enrolled + * so that a warning can be issued for any spin locks enrolled later. + */ +static int witness_spin_warn = 0; + +/* Trim useless garbage from filenames. */ +static const char * +fixup_filename(const char *file) +{ + + if (file == NULL) + return (NULL); + while (strncmp(file, "../", 3) == 0) + file += 3; + return (file); +} + +/* + * The WITNESS-enabled diagnostic code. Note that the witness code does + * assume that the early boot is single-threaded at least until after this + * routine is completed. + */ +void +witness_initialize(void) +{ + struct lock_object *lock; + struct witness *w; + int i; + + w_data = (void *)uvm_pageboot_alloc(sizeof(struct witness) * + witness_count); + memset(w_data, 0, sizeof(struct witness) * witness_count); + + w_rmatrix = (void *)uvm_pageboot_alloc(sizeof(*w_rmatrix) * + (witness_count + 1)); + + for (i = 0; i < witness_count + 1; i++) { + w_rmatrix[i] = (void *)uvm_pageboot_alloc( + sizeof(*w_rmatrix[i]) * (witness_count + 1)); + memset(w_rmatrix[i], 0, sizeof(*w_rmatrix[i]) * + (witness_count + 1)); + } + + CTR1(KTR_WITNESS, "%s: initializing witness", __func__); + mtx_init_flags(&w_mtx, IPL_HIGH, "witness lock", MTX_NOWITNESS); + for (i = witness_count - 1; i >= 0; i--) { + w = &w_data[i]; + memset(w, 0, sizeof(*w)); + w_data[i].w_index = i; /* Witness index never changes. */ + witness_free(w); + } + KASSERTMSG(SIMPLEQ_FIRST(&w_free)->w_index == 0, + "%s: Invalid list of free witness objects", __func__); + + /* Witness with index 0 is not used to aid in debugging. */ + SIMPLEQ_REMOVE_HEAD(&w_free, w_list); + w_free_cnt--; + + for (i = 0; i < witness_count; i++) { + memset(w_rmatrix[i], 0, sizeof(*w_rmatrix[i]) * + (witness_count + 1)); + } + + for (i = 0; i < LOCK_CHILDCOUNT; i++) + witness_lock_list_free(&w_locklistdata[i]); + witness_init_hash_tables(); + witness_spin_warn = 1; + + /* Iterate through all locks and add them to witness. */ + for (i = 0; pending_locks[i].wh_lock != NULL; i++) { + lock = pending_locks[i].wh_lock; + KASSERTMSG(lock->lo_flags & LO_WITNESS, + "%s: lock %s is on pending list but not LO_WITNESS", + __func__, lock->lo_name); + lock->lo_witness = enroll(pending_locks[i].wh_type, + lock->lo_name, LOCK_CLASS(lock)); + } + + /* Mark the witness code as being ready for use. */ + witness_cold = 0; +} + +void +witness_init(struct lock_object *lock, struct lock_type *type) +{ + struct lock_class *class; + + /* Various sanity checks. */ + class = LOCK_CLASS(lock); + if ((lock->lo_flags & LO_RECURSABLE) != 0 && + (class->lc_flags & LC_RECURSABLE) == 0) + panic("%s: lock (%s) %s can not be recursable", + __func__, class->lc_name, lock->lo_name); + if ((lock->lo_flags & LO_SLEEPABLE) != 0 && + (class->lc_flags & LC_SLEEPABLE) == 0) + panic("%s: lock (%s) %s can not be sleepable", + __func__, class->lc_name, lock->lo_name); + if ((lock->lo_flags & LO_UPGRADABLE) != 0 && + (class->lc_flags & LC_UPGRADABLE) == 0) + panic("%s: lock (%s) %s can not be upgradable", + __func__, class->lc_name, lock->lo_name); + + /* + * If we shouldn't watch this lock, then just clear lo_witness. + * Otherwise, if witness_cold is set, then it is too early to + * enroll this lock, so defer it to witness_initialize() by adding + * it to the pending_locks list. If it is not too early, then enroll + * the lock now. + */ + if (witness_watch < 1 || panicstr != NULL || + (lock->lo_flags & LO_WITNESS) == 0) + lock->lo_witness = NULL; + else if (witness_cold) { + pending_locks[pending_cnt].wh_lock = lock; + pending_locks[pending_cnt++].wh_type = type; + if (pending_cnt > WITNESS_PENDLIST) + panic("%s: pending locks list is too small, " + "increase WITNESS_PENDLIST\n", + __func__); + } else + lock->lo_witness = enroll(type, lock->lo_name, class); +} + +#ifdef DDB +static void +witness_ddb_compute_levels(void) +{ + struct witness *w; + + /* + * First clear all levels. + */ + SIMPLEQ_FOREACH(w, &w_all, w_list) + w->w_ddb_level = -1; + + /* + * Look for locks with no parents and level all their descendants. + */ + SIMPLEQ_FOREACH(w, &w_all, w_list) { + + /* If the witness has ancestors (is not a root), skip it. */ + if (w->w_num_ancestors > 0) + continue; + witness_ddb_level_descendants(w, 0); + } +} + +static void +witness_ddb_level_descendants(struct witness *w, int l) +{ + int i; + + if (w->w_ddb_level >= l) + return; + + w->w_ddb_level = l; + l++; + + for (i = 1; i <= w_max_used_index; i++) { + if (w_rmatrix[w->w_index][i] & WITNESS_PARENT) + witness_ddb_level_descendants(&w_data[i], l); + } +} + +static void +witness_ddb_display_descendants(int(*prnt)(const char *fmt, ...), + struct witness *w, int indent) +{ + int i; + + for (i = 0; i < indent; i++) + prnt(" "); + prnt("%s (type: %s, depth: %d)", + w->w_type->lt_name, w->w_class->lc_name, w->w_ddb_level); + if (w->w_displayed) { + prnt(" -- (already displayed)\n"); + return; + } + w->w_displayed = 1; + if (w->w_file != NULL && w->w_line != 0) + prnt(" -- last acquired @ %s:%d\n", fixup_filename(w->w_file), + w->w_line); + else + prnt(" -- never acquired\n"); + indent++; + WITNESS_INDEX_ASSERT(w->w_index); + for (i = 1; i <= w_max_used_index; i++) { + if (w_rmatrix[w->w_index][i] & WITNESS_PARENT) + witness_ddb_display_descendants(prnt, &w_data[i], + indent); + } +} + +static void +witness_ddb_display_list(int(*prnt)(const char *fmt, ...), + struct witness_list *list) +{ + struct witness *w; + + SIMPLEQ_FOREACH(w, list, w_typelist) { + if (w->w_file == NULL || w->w_ddb_level > 0) + continue; + + /* This lock has no anscestors - display its descendants. */ + witness_ddb_display_descendants(prnt, w, 0); + } +} + +static void +witness_ddb_display(int(*prnt)(const char *fmt, ...)) +{ + struct witness *w; + + KASSERTMSG(witness_cold == 0, "%s: witness_cold", __func__); + witness_ddb_compute_levels(); + + /* Clear all the displayed flags. */ + SIMPLEQ_FOREACH(w, &w_all, w_list) + w->w_displayed = 0; + + /* + * First, handle sleep locks which have been acquired at least + * once. + */ + prnt("Sleep locks:\n"); + witness_ddb_display_list(prnt, &w_sleep); + + /* + * Now do spin locks which have been acquired at least once. + */ + prnt("\nSpin locks:\n"); + witness_ddb_display_list(prnt, &w_spin); + + /* + * Finally, any locks which have not been acquired yet. + */ + prnt("\nLocks which were never acquired:\n"); + SIMPLEQ_FOREACH(w, &w_all, w_list) { + if (w->w_file != NULL) + continue; + prnt("%s (type: %s, depth: %d)\n", w->w_type->lt_name, + w->w_class->lc_name, w->w_ddb_level); + } +} +#endif /* DDB */ + +int +witness_defineorder(struct lock_object *lock1, struct lock_object *lock2) +{ + + if (witness_watch == -1 || panicstr != NULL) + return (0); + + /* Require locks that witness knows about. */ + if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL || + lock2->lo_witness == NULL) + return (EINVAL); + + MUTEX_ASSERT_UNLOCKED(&w_mtx); + mtx_enter(&w_mtx); + + /* + * If we already have either an explicit or implied lock order that + * is the other way around, then return an error. + */ + if (witness_watch && + isitmydescendant(lock2->lo_witness, lock1->lo_witness)) { + mtx_leave(&w_mtx); + return (EINVAL); + } + + /* Try to add the new order. */ + CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, + lock2->lo_witness->w_name, lock1->lo_witness->w_name); + itismychild(lock1->lo_witness, lock2->lo_witness); + mtx_leave(&w_mtx); + return (0); +} + +void +witness_checkorder(struct lock_object *lock, int flags, const char *file, + int line, struct lock_object *interlock) +{ + struct lock_list_entry *lock_list, *lle; + struct lock_instance *lock1, *lock2, *plock; + struct lock_class *class, *iclass; + struct proc *p; + struct witness *w, *w1; + int i, j, s; + + if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL || + panicstr != NULL) + return; + + w = lock->lo_witness; + class = LOCK_CLASS(lock); + + if (w == NULL) + w = lock->lo_witness = + enroll(lock->lo_type, lock->lo_name, class); + + p = curproc; + + if (class->lc_flags & LC_SLEEPLOCK) { + /* + * Since spin locks include a critical section, this check + * implicitly enforces a lock order of all sleep locks before + * all spin locks. + */ + lock_list = witness_cpu[cpu_number()].wc_spinlocks; + if (lock_list != NULL && lock_list->ll_count > 0) { + panic("acquiring blockable sleep lock with " + "spinlock or critical section held (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + } + + /* + * If this is the first lock acquired then just return as + * no order checking is needed. + */ + lock_list = p->p_sleeplocks; + if (lock_list == NULL || lock_list->ll_count == 0) + return; + } else { + + /* + * If this is the first lock, just return as no order + * checking is needed. + */ + lock_list = witness_cpu[cpu_number()].wc_spinlocks; + if (lock_list == NULL || lock_list->ll_count == 0) + return; + } + + s = splhigh(); + + /* + * Check to see if we are recursing on a lock we already own. If + * so, make sure that we don't mismatch exclusive and shared lock + * acquires. + */ + lock1 = find_instance(lock_list, lock); + if (lock1 != NULL) { + if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && + (flags & LOP_EXCLUSIVE) == 0) { + witness_output("shared lock of (%s) %s @ %s:%d\n", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + witness_output("while exclusively locked from %s:%d\n", + fixup_filename(lock1->li_file), lock1->li_line); + panic("excl->share"); + } + if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && + (flags & LOP_EXCLUSIVE) != 0) { + witness_output("exclusive lock of (%s) %s @ %s:%d\n", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + witness_output("while share locked from %s:%d\n", + fixup_filename(lock1->li_file), lock1->li_line); + panic("share->excl"); + } + goto out_splx; + } + + /* Warn if the interlock is not locked exactly once. */ + if (interlock != NULL) { + iclass = LOCK_CLASS(interlock); + lock1 = find_instance(lock_list, interlock); + if (lock1 == NULL) + panic("interlock (%s) %s not locked @ %s:%d", + iclass->lc_name, interlock->lo_name, + fixup_filename(file), line); + else if ((lock1->li_flags & LI_RECURSEMASK) != 0) + panic("interlock (%s) %s recursed @ %s:%d", + iclass->lc_name, interlock->lo_name, + fixup_filename(file), line); + } + + /* + * Find the previously acquired lock, but ignore interlocks. + */ + plock = &lock_list->ll_children[lock_list->ll_count - 1]; + if (interlock != NULL && plock->li_lock == interlock) { + if (lock_list->ll_count > 1) + plock = + &lock_list->ll_children[lock_list->ll_count - 2]; + else { + lle = lock_list->ll_next; + + /* + * The interlock is the only lock we hold, so + * simply return. + */ + if (lle == NULL) + goto out_splx; + plock = &lle->ll_children[lle->ll_count - 1]; + } + } + + /* + * Try to perform most checks without a lock. If this succeeds we + * can skip acquiring the lock and return success. Otherwise we redo + * the check with the lock held to handle races with concurrent updates. + */ + w1 = plock->li_lock->lo_witness; + if (witness_lock_order_check(w1, w)) + goto out_splx; + + mtx_enter(&w_mtx); + if (witness_lock_order_check(w1, w)) + goto out; + + witness_lock_order_add(w1, w); + + /* + * Check for duplicate locks of the same type. Note that we only + * have to check for this on the last lock we just acquired. Any + * other cases will be caught as lock order violations. + */ + if (w1 == w) { + i = w->w_index; + if (!(lock->lo_flags & LO_DUPOK) && !(flags & LOP_DUPOK) && + !(w_rmatrix[i][i] & WITNESS_REVERSAL)) { + w_rmatrix[i][i] |= WITNESS_REVERSAL; + w->w_reversed = 1; + mtx_leave(&w_mtx); + witness_output( + "acquiring duplicate lock of same type: \"%s\"\n", + w->w_type->lt_name); + witness_output(" 1st %s @ %s:%d\n", plock->li_lock->lo_name, + fixup_filename(plock->li_file), plock->li_line); + witness_output(" 2nd %s @ %s:%d\n", lock->lo_name, + fixup_filename(file), line); + witness_debugger(1, __func__); + } else + mtx_leave(&w_mtx); + goto out_splx; + } + MUTEX_ASSERT_LOCKED(&w_mtx); + + /* + * If we know that the lock we are acquiring comes after + * the lock we most recently acquired in the lock order tree, + * then there is no need for any further checks. + */ + if (isitmychild(w1, w)) + goto out; + + for (j = 0, lle = lock_list; lle != NULL; lle = lle->ll_next) { + for (i = lle->ll_count - 1; i >= 0; i--, j++) { + + KASSERT(j < LOCK_CHILDCOUNT * LOCK_NCHILDREN); + lock1 = &lle->ll_children[i]; + + /* + * Ignore the interlock. + */ + if (interlock == lock1->li_lock) + continue; + + /* + * If this lock doesn't undergo witness checking, + * then skip it. + */ + w1 = lock1->li_lock->lo_witness; + if (w1 == NULL) { + KASSERTMSG((lock1->li_lock->lo_flags & + LO_WITNESS) == 0, + "lock missing witness structure"); + continue; + } + + /* + * If we are locking Giant and this is a sleepable + * lock, then skip it. + */ + if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 && + lock == &kernel_lock.mpl_lock_obj) + continue; + + /* + * If we are locking a sleepable lock and this lock + * is Giant, then skip it. + */ + if ((lock->lo_flags & LO_SLEEPABLE) != 0 && + lock1->li_lock == &kernel_lock.mpl_lock_obj) + continue; + + /* + * If we are locking a sleepable lock and this lock + * isn't sleepable, we want to treat it as a lock + * order violation to enfore a general lock order of + * sleepable locks before non-sleepable locks. + */ + if (((lock->lo_flags & LO_SLEEPABLE) != 0 && + (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) + goto reversal; + + /* + * If we are locking Giant and this is a non-sleepable + * lock, then treat it as a reversal. + */ + if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && + lock == &kernel_lock.mpl_lock_obj) + goto reversal; + + /* + * Check the lock order hierarchy for a reveresal. + */ + if (!isitmydescendant(w, w1)) + continue; + reversal: + + /* + * We have a lock order violation, check to see if it + * is allowed or has already been yelled about. + */ + + /* Bail if this violation is known */ + if (w_rmatrix[w1->w_index][w->w_index] & WITNESS_REVERSAL) + goto out; + + /* Record this as a violation */ + w_rmatrix[w1->w_index][w->w_index] |= WITNESS_REVERSAL; + w_rmatrix[w->w_index][w1->w_index] |= WITNESS_REVERSAL; + w->w_reversed = w1->w_reversed = 1; + witness_increment_graph_generation(); + mtx_leave(&w_mtx); + + /* + * There are known LORs between VNODE locks. They are + * not an indication of a bug. VNODE locks are flagged + * as such (LO_IS_VNODE) and we don't yell if the LOR + * is between 2 VNODE locks. + */ + if ((lock->lo_flags & LO_IS_VNODE) != 0 && + (lock1->li_lock->lo_flags & LO_IS_VNODE) != 0) + goto out_splx; + + /* + * Ok, yell about it. + */ + if (((lock->lo_flags & LO_SLEEPABLE) != 0 && + (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) + witness_output( + "lock order reversal: (sleepable after non-sleepable)\n"); + else if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 + && lock == &kernel_lock.mpl_lock_obj) + witness_output( + "lock order reversal: (Giant after non-sleepable)\n"); + else + witness_output("lock order reversal:\n"); + + /* + * Try to locate an earlier lock with + * witness w in our list. + */ + do { + lock2 = &lle->ll_children[i]; + KASSERT(lock2->li_lock != NULL); + if (lock2->li_lock->lo_witness == w) + break; + if (i == 0 && lle->ll_next != NULL) { + lle = lle->ll_next; + i = lle->ll_count - 1; + KASSERT(i >= 0 && i < LOCK_NCHILDREN); + } else + i--; + } while (i >= 0); + if (i < 0) { + witness_output(" 1st %p %s (%s) @ %s:%d\n", + lock1->li_lock, lock1->li_lock->lo_name, + w1->w_type->lt_name, + fixup_filename(lock1->li_file), + lock1->li_line); + witness_output(" 2nd %p %s (%s) @ %s:%d\n", + lock, lock->lo_name, w->w_type->lt_name, + fixup_filename(file), line); + } else { + witness_output(" 1st %p %s (%s) @ %s:%d\n", + lock2->li_lock, lock2->li_lock->lo_name, + lock2->li_lock->lo_witness->w_type->lt_name, + fixup_filename(lock2->li_file), + lock2->li_line); + witness_output(" 2nd %p %s (%s) @ %s:%d\n", + lock1->li_lock, lock1->li_lock->lo_name, + w1->w_type->lt_name, + fixup_filename(lock1->li_file), + lock1->li_line); + witness_output(" 3rd %p %s (%s) @ %s:%d\n", lock, + lock->lo_name, w->w_type->lt_name, + fixup_filename(file), line); + } + witness_debugger(1, __func__); + goto out_splx; + } + } + + /* + * If requested, build a new lock order. However, don't build a new + * relationship between a sleepable lock and Giant if it is in the + * wrong direction. The correct lock order is that sleepable locks + * always come before Giant. + */ + if (flags & LOP_NEWORDER && + !(plock->li_lock == &kernel_lock.mpl_lock_obj && + (lock->lo_flags & LO_SLEEPABLE) != 0)) { + CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, + w->w_type->lt_name, + plock->li_lock->lo_witness->w_type->lt_name); + itismychild(plock->li_lock->lo_witness, w); + } +out: + mtx_leave(&w_mtx); +out_splx: + splx(s); +} + +void +witness_lock(struct lock_object *lock, int flags, const char *file, int line) +{ + struct lock_list_entry **lock_list, *lle; + struct lock_instance *instance; + struct proc *p; + struct witness *w; + int s; + + if (witness_cold || witness_watch == -1 || lock->lo_witness == NULL || + panicstr != NULL) + return; + + w = lock->lo_witness; + if (w == NULL) + w = lock->lo_witness = + enroll(lock->lo_type, lock->lo_name, LOCK_CLASS(lock)); + + p = curproc; + + /* Determine lock list for this lock. */ + if (LOCK_CLASS(lock)->lc_flags & LC_SLEEPLOCK) + lock_list = &p->p_sleeplocks; + else + lock_list = &witness_cpu[cpu_number()].wc_spinlocks; + + s = splhigh(); + + /* Check to see if we are recursing on a lock we already own. */ + instance = find_instance(*lock_list, lock); + if (instance != NULL) { + instance->li_flags++; + CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, + p->p_p->ps_pid, lock->lo_name, + instance->li_flags & LI_RECURSEMASK); + instance->li_file = file; + instance->li_line = line; + goto out; + } + + /* Update per-witness last file and line acquire. */ + w->w_file = file; + w->w_line = line; + + /* Find the next open lock instance in the list and fill it. */ + lle = *lock_list; + if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { + lle = witness_lock_list_get(); + if (lle == NULL) + goto out; + lle->ll_next = *lock_list; + CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, + p->p_p->ps_pid, lle); + *lock_list = lle; + } + instance = &lle->ll_children[lle->ll_count++]; + instance->li_lock = lock; + instance->li_line = line; + instance->li_file = file; + if ((flags & LOP_EXCLUSIVE) != 0) + instance->li_flags = LI_EXCLUSIVE; + else + instance->li_flags = 0; + CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, + p->p_p->ps_pid, lock->lo_name, lle->ll_count - 1); +out: + splx(s); +} + +void +witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) +{ + struct lock_instance *instance; + struct lock_class *class; + int s; + + KASSERTMSG(witness_cold == 0, "%s: witness_cold", __func__); + if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) + return; + class = LOCK_CLASS(lock); + if (witness_watch) { + if ((lock->lo_flags & LO_UPGRADABLE) == 0) + panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + if ((class->lc_flags & LC_SLEEPLOCK) == 0) + panic("upgrade of non-sleep lock (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + } + s = splhigh(); + instance = find_instance(curproc->p_sleeplocks, lock); + if (instance == NULL) { + panic("upgrade of unlocked lock (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + goto out; + } + if (witness_watch) { + if ((instance->li_flags & LI_EXCLUSIVE) != 0) + panic("upgrade of exclusive lock (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + if ((instance->li_flags & LI_RECURSEMASK) != 0) + panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", + class->lc_name, lock->lo_name, + instance->li_flags & LI_RECURSEMASK, + fixup_filename(file), line); + } + instance->li_flags |= LI_EXCLUSIVE; +out: + splx(s); +} + +void +witness_downgrade(struct lock_object *lock, int flags, const char *file, + int line) +{ + struct lock_instance *instance; + struct lock_class *class; + int s; + + KASSERTMSG(witness_cold == 0, "%s: witness_cold", __func__); + if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) + return; + class = LOCK_CLASS(lock); + if (witness_watch) { + if ((lock->lo_flags & LO_UPGRADABLE) == 0) + panic( + "downgrade of non-upgradable lock (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + if ((class->lc_flags & LC_SLEEPLOCK) == 0) + panic("downgrade of non-sleep lock (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + } + s = splhigh(); + instance = find_instance(curproc->p_sleeplocks, lock); + if (instance == NULL) { + panic("downgrade of unlocked lock (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + goto out; + } + if (witness_watch) { + if ((instance->li_flags & LI_EXCLUSIVE) == 0) + panic("downgrade of shared lock (%s) %s @ %s:%d", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + if ((instance->li_flags & LI_RECURSEMASK) != 0) + panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", + class->lc_name, lock->lo_name, + instance->li_flags & LI_RECURSEMASK, + fixup_filename(file), line); + } + instance->li_flags &= ~LI_EXCLUSIVE; +out: + splx(s); +} + +void +witness_unlock(struct lock_object *lock, int flags, const char *file, int line) +{ + struct lock_list_entry **lock_list, *lle; + struct lock_instance *instance; + struct lock_class *class; + struct proc *p; + int i, j; + int s; + + if (witness_cold || lock->lo_witness == NULL || panicstr != NULL) + return; + p = curproc; + class = LOCK_CLASS(lock); + + /* Find lock instance associated with this lock. */ + if (class->lc_flags & LC_SLEEPLOCK) + lock_list = &p->p_sleeplocks; + else + lock_list = &witness_cpu[cpu_number()].wc_spinlocks; + + s = splhigh(); + + lle = *lock_list; + for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) + for (i = 0; i < (*lock_list)->ll_count; i++) { + instance = &(*lock_list)->ll_children[i]; + if (instance->li_lock == lock) + goto found; + } + + /* + * When disabling WITNESS through witness_watch we could end up in + * having registered locks in the p_sleeplocks queue. + * We have to make sure we flush these queues, so just search for + * eventual register locks and remove them. + */ + if (witness_watch > 0) { + panic("lock (%s) %s not locked @ %s:%d", class->lc_name, + lock->lo_name, fixup_filename(file), line); + } + goto out; + +found: + + /* First, check for shared/exclusive mismatches. */ + if ((instance->li_flags & LI_EXCLUSIVE) != 0 && witness_watch > 0 && + (flags & LOP_EXCLUSIVE) == 0) { + witness_output("shared unlock of (%s) %s @ %s:%d\n", + class->lc_name, lock->lo_name, fixup_filename(file), line); + witness_output("while exclusively locked from %s:%d\n", + fixup_filename(instance->li_file), instance->li_line); + panic("excl->ushare"); + } + if ((instance->li_flags & LI_EXCLUSIVE) == 0 && witness_watch > 0 && + (flags & LOP_EXCLUSIVE) != 0) { + witness_output("exclusive unlock of (%s) %s @ %s:%d\n", + class->lc_name, lock->lo_name, fixup_filename(file), line); + witness_output("while share locked from %s:%d\n", + fixup_filename(instance->li_file), + instance->li_line); + panic("share->uexcl"); + } + /* If we are recursed, unrecurse. */ + if ((instance->li_flags & LI_RECURSEMASK) > 0) { + CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__, + p->p_p->ps_pid, instance->li_lock->lo_name, + instance->li_flags); + instance->li_flags--; + goto out; + } + /* The lock is now being dropped, check for NORELEASE flag */ + if ((instance->li_flags & LI_NORELEASE) != 0 && witness_watch > 0) { + witness_output("forbidden unlock of (%s) %s @ %s:%d\n", + class->lc_name, lock->lo_name, fixup_filename(file), line); + panic("lock marked norelease"); + } + + /* Otherwise, remove this item from the list. */ + CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__, + p->p_p->ps_pid, instance->li_lock->lo_name, + (*lock_list)->ll_count - 1); + for (j = i; j < (*lock_list)->ll_count - 1; j++) + (*lock_list)->ll_children[j] = + (*lock_list)->ll_children[j + 1]; + (*lock_list)->ll_count--; + + /* + * In order to reduce contention on w_mtx, we want to keep always an + * head object into lists so that frequent allocation from the + * free witness pool (and subsequent locking) is avoided. + * In order to maintain the current code simple, when the head + * object is totally unloaded it means also that we do not have + * further objects in the list, so the list ownership needs to be + * hand over to another object if the current head needs to be freed. + */ + if ((*lock_list)->ll_count == 0) { + if (*lock_list == lle) { + if (lle->ll_next == NULL) + goto out; + } else + lle = *lock_list; + *lock_list = lle->ll_next; + CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__, + p->p_p->ps_pid, lle); + witness_lock_list_free(lle); + } +out: + splx(s); +} + +void +witness_thread_exit(struct proc *p) +{ + struct lock_list_entry *lle; + int i, n; + + lle = p->p_sleeplocks; + if (lle == NULL || panicstr != NULL) + return; + if (lle->ll_count != 0) { + for (n = 0; lle != NULL; lle = lle->ll_next) + for (i = lle->ll_count - 1; i >= 0; i--) { + if (n == 0) + witness_output("Thread %p exiting with " + "the following locks held:\n", p); + n++; + witness_list_lock(&lle->ll_children[i], + witness_output); + } + panic("Thread %p cannot exit while holding sleeplocks\n", p); + } + KASSERT(lle->ll_next == NULL); + witness_lock_list_free(lle); +} + +/* + * Warn if any locks other than 'lock' are held. Flags can be passed in to + * exempt Giant and sleepable locks from the checks as well. If any + * non-exempt locks are held, then a supplied message is printed to the + * output channel along with a list of the offending locks. If indicated in the + * flags then a failure results in a panic as well. + */ +int +witness_warn(int flags, struct lock_object *lock, const char *fmt, ...) +{ + struct lock_list_entry *lock_list, *lle; + struct lock_instance *lock1; + struct proc *p; + va_list ap; + int i, n; + + if (witness_cold || witness_watch < 1 || panicstr != NULL) + return (0); + n = 0; + p = curproc; + for (lle = p->p_sleeplocks; lle != NULL; lle = lle->ll_next) + for (i = lle->ll_count - 1; i >= 0; i--) { + lock1 = &lle->ll_children[i]; + if (lock1->li_lock == lock) + continue; + if (flags & WARN_KERNELOK && + lock1->li_lock == &kernel_lock.mpl_lock_obj) + continue; + if (flags & WARN_SLEEPOK && + (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) + continue; + if (n == 0) { + va_start(ap, fmt); + vprintf(fmt, ap); + va_end(ap); + printf(" with the following %slocks held:\n", + (flags & WARN_SLEEPOK) != 0 ? + "non-sleepable " : ""); + } + n++; + witness_list_lock(lock1, printf); + } + + lock_list = witness_cpu[cpu_number()].wc_spinlocks; + if (lock_list != NULL && lock_list->ll_count != 0) { + /* + * We should only have one spinlock and as long as + * the flags cannot match for this locks class, + * check if the first spinlock is the one curproc + * should hold. + */ + lock1 = &lock_list->ll_children[lock_list->ll_count - 1]; + if (lock_list->ll_count == 1 && lock_list->ll_next == NULL && + lock1->li_lock == lock && n == 0) + return (0); + + va_start(ap, fmt); + vprintf(fmt, ap); + va_end(ap); + printf(" with the following %slocks held:\n", + (flags & WARN_SLEEPOK) != 0 ? "non-sleepable " : ""); + n += witness_list_locks(&lock_list, printf); + } + if (flags & WARN_PANIC && n) + panic("%s", __func__); + else + witness_debugger(n, __func__); + return (n); +} + +const char * +witness_file(struct lock_object *lock) +{ + struct witness *w; + + if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL) + return ("?"); + w = lock->lo_witness; + return (w->w_file); +} + +int +witness_line(struct lock_object *lock) +{ + struct witness *w; + + if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL) + return (0); + w = lock->lo_witness; + return (w->w_line); +} + +static struct witness * +enroll(struct lock_type *type, const char *subtype, + struct lock_class *lock_class) +{ + struct witness *w; + struct witness_list *typelist; + + KASSERT(type != NULL); + + if (witness_watch == -1 || panicstr != NULL) + return (NULL); + if ((lock_class->lc_flags & LC_SPINLOCK)) { + if (witness_skipspin) + return (NULL); + else + typelist = &w_spin; + } else if ((lock_class->lc_flags & LC_SLEEPLOCK)) { + typelist = &w_sleep; + } else { + panic("lock class %s is not sleep or spin", + lock_class->lc_name); + return (NULL); + } + + mtx_enter(&w_mtx); + w = witness_hash_get(type, subtype); + if (w) + goto found; + if ((w = witness_get()) == NULL) + return (NULL); + w->w_type = type; + w->w_subtype = subtype; + w->w_class = lock_class; + SIMPLEQ_INSERT_HEAD(&w_all, w, w_list); + if (lock_class->lc_flags & LC_SPINLOCK) { + SIMPLEQ_INSERT_HEAD(&w_spin, w, w_typelist); + w_spin_cnt++; + } else if (lock_class->lc_flags & LC_SLEEPLOCK) { + SIMPLEQ_INSERT_HEAD(&w_sleep, w, w_typelist); + w_sleep_cnt++; + } + + /* Insert new witness into the hash */ + witness_hash_put(w); + witness_increment_graph_generation(); + mtx_leave(&w_mtx); + return (w); +found: + mtx_leave(&w_mtx); + if (lock_class != w->w_class) + panic("lock (%s) %s does not match earlier (%s) lock", + type->lt_name, lock_class->lc_name, w->w_class->lc_name); + return (w); +} + +static void +adopt(struct witness *parent, struct witness *child) +{ + int pi, ci, i, j; + + if (witness_cold == 0) + MUTEX_ASSERT_LOCKED(&w_mtx); + + /* If the relationship is already known, there's no work to be done. */ + if (isitmychild(parent, child)) + return; + + /* When the structure of the graph changes, bump up the generation. */ + witness_increment_graph_generation(); + + /* + * The hard part ... create the direct relationship, then propagate all + * indirect relationships. + */ + pi = parent->w_index; + ci = child->w_index; + WITNESS_INDEX_ASSERT(pi); + WITNESS_INDEX_ASSERT(ci); + KASSERT(pi != ci); + w_rmatrix[pi][ci] |= WITNESS_PARENT; + w_rmatrix[ci][pi] |= WITNESS_CHILD; + + /* + * If parent was not already an ancestor of child, + * then we increment the descendant and ancestor counters. + */ + if ((w_rmatrix[pi][ci] & WITNESS_ANCESTOR) == 0) { + parent->w_num_descendants++; + child->w_num_ancestors++; + } + + /* + * Find each ancestor of 'pi'. Note that 'pi' itself is counted as + * an ancestor of 'pi' during this loop. + */ + for (i = 1; i <= w_max_used_index; i++) { + if ((w_rmatrix[i][pi] & WITNESS_ANCESTOR_MASK) == 0 && + (i != pi)) + continue; + + /* Find each descendant of 'i' and mark it as a descendant. */ + for (j = 1; j <= w_max_used_index; j++) { + + /* + * Skip children that are already marked as + * descendants of 'i'. + */ + if (w_rmatrix[i][j] & WITNESS_ANCESTOR_MASK) + continue; + + /* + * We are only interested in descendants of 'ci'. Note + * that 'ci' itself is counted as a descendant of 'ci'. + */ + if ((w_rmatrix[ci][j] & WITNESS_ANCESTOR_MASK) == 0 && + (j != ci)) + continue; + w_rmatrix[i][j] |= WITNESS_ANCESTOR; + w_rmatrix[j][i] |= WITNESS_DESCENDANT; + w_data[i].w_num_descendants++; + w_data[j].w_num_ancestors++; + + /* + * Make sure we aren't marking a node as both an + * ancestor and descendant. We should have caught + * this as a lock order reversal earlier. + */ + if ((w_rmatrix[i][j] & WITNESS_ANCESTOR_MASK) && + (w_rmatrix[i][j] & WITNESS_DESCENDANT_MASK)) { + printf("witness rmatrix paradox! [%d][%d]=%d " + "both ancestor and descendant\n", + i, j, w_rmatrix[i][j]); +#ifdef DDB + db_stack_dump(); +#endif + printf("Witness disabled.\n"); + witness_watch = -1; + } + if ((w_rmatrix[j][i] & WITNESS_ANCESTOR_MASK) && + (w_rmatrix[j][i] & WITNESS_DESCENDANT_MASK)) { + printf("witness rmatrix paradox! [%d][%d]=%d " + "both ancestor and descendant\n", + j, i, w_rmatrix[j][i]); +#ifdef DDB + db_stack_dump(); +#endif + printf("Witness disabled.\n"); + witness_watch = -1; + } + } + } +} + +static void +itismychild(struct witness *parent, struct witness *child) +{ + int unlocked; + + KASSERT(child != NULL && parent != NULL); + if (witness_cold == 0) + MUTEX_ASSERT_LOCKED(&w_mtx); + + if (!witness_lock_type_equal(parent, child)) { + if (witness_cold == 0) { + unlocked = 1; + mtx_leave(&w_mtx); + } else { + unlocked = 0; + } + panic( + "%s: parent \"%s\" (%s) and child \"%s\" (%s) are not " + "the same lock type", __func__, parent->w_type->lt_name, + parent->w_class->lc_name, child->w_type->lt_name, + child->w_class->lc_name); + if (unlocked) + mtx_enter(&w_mtx); + } + adopt(parent, child); +} + +/* + * Generic code for the isitmy*() functions. The rmask parameter is the + * expected relationship of w1 to w2. + */ +static int +_isitmyx(struct witness *w1, struct witness *w2, int rmask, const char *fname) +{ + unsigned char r1, r2; + int i1, i2; + + i1 = w1->w_index; + i2 = w2->w_index; + WITNESS_INDEX_ASSERT(i1); + WITNESS_INDEX_ASSERT(i2); + r1 = w_rmatrix[i1][i2] & WITNESS_RELATED_MASK; + r2 = w_rmatrix[i2][i1] & WITNESS_RELATED_MASK; + + /* The flags on one better be the inverse of the flags on the other */ + if (!((WITNESS_ATOD(r1) == r2 && WITNESS_DTOA(r2) == r1) || + (WITNESS_DTOA(r1) == r2 && WITNESS_ATOD(r2) == r1))) { + /* Don't squawk if we're potentially racing with an update. */ + if (w_mtx.mtx_owner != curcpu()) + return (0); + printf("%s: rmatrix mismatch between %s (index %d) and %s " + "(index %d): w_rmatrix[%d][%d] == %hx but " + "w_rmatrix[%d][%d] == %hx\n", + fname, w1->w_type->lt_name, i1, w2->w_type->lt_name, + i2, i1, i2, r1, + i2, i1, r2); +#ifdef DDB + db_stack_dump(); +#endif + printf("Witness disabled.\n"); + witness_watch = -1; + } + return (r1 & rmask); +} + +/* + * Checks if @child is a direct child of @parent. + */ +static int +isitmychild(struct witness *parent, struct witness *child) +{ + + return (_isitmyx(parent, child, WITNESS_PARENT, __func__)); +} + +/* + * Checks if @descendant is a direct or inderect descendant of @ancestor. + */ +static int +isitmydescendant(struct witness *ancestor, struct witness *descendant) +{ + + return (_isitmyx(ancestor, descendant, WITNESS_ANCESTOR_MASK, + __func__)); +} + +static struct witness * +witness_get(void) +{ + struct witness *w; + int index; + + if (witness_cold == 0) + MUTEX_ASSERT_LOCKED(&w_mtx); + + if (witness_watch == -1) { + mtx_leave(&w_mtx); + return (NULL); + } + if (SIMPLEQ_EMPTY(&w_free)) { + witness_watch = -1; + mtx_leave(&w_mtx); + printf("WITNESS: unable to allocate a new witness object\n"); + return (NULL); + } + w = SIMPLEQ_FIRST(&w_free); + SIMPLEQ_REMOVE_HEAD(&w_free, w_list); + w_free_cnt--; + index = w->w_index; + KASSERT(index > 0 && index == w_max_used_index + 1 && + index < witness_count); + bzero(w, sizeof(*w)); + w->w_index = index; + if (index > w_max_used_index) + w_max_used_index = index; + return (w); +} + +static void +witness_free(struct witness *w) +{ + + SIMPLEQ_INSERT_HEAD(&w_free, w, w_list); + w_free_cnt++; +} + +static struct lock_list_entry * +witness_lock_list_get(void) +{ + struct lock_list_entry *lle; + + if (witness_watch == -1) + return (NULL); + mtx_enter(&w_mtx); + lle = w_lock_list_free; + if (lle == NULL) { + witness_watch = -1; + mtx_leave(&w_mtx); + printf("%s: witness exhausted\n", __func__); + return (NULL); + } + w_lock_list_free = lle->ll_next; + mtx_leave(&w_mtx); + bzero(lle, sizeof(*lle)); + return (lle); +} + +static void +witness_lock_list_free(struct lock_list_entry *lle) +{ + mtx_enter(&w_mtx); + lle->ll_next = w_lock_list_free; + w_lock_list_free = lle; + mtx_leave(&w_mtx); +} + +static struct lock_instance * +find_instance(struct lock_list_entry *list, const struct lock_object *lock) +{ + struct lock_list_entry *lle; + struct lock_instance *instance; + int i; + + for (lle = list; lle != NULL; lle = lle->ll_next) { + for (i = lle->ll_count - 1; i >= 0; i--) { + instance = &lle->ll_children[i]; + if (instance->li_lock == lock) + return (instance); + } + } + return (NULL); +} + +static void +witness_list_lock(struct lock_instance *instance, + int (*prnt)(const char *fmt, ...)) +{ + struct lock_object *lock; + + lock = instance->li_lock; + prnt("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ? + "exclusive" : "shared", LOCK_CLASS(lock)->lc_name, lock->lo_name); + prnt(" r = %d (%p) locked @ %s:%d\n", + instance->li_flags & LI_RECURSEMASK, lock, + fixup_filename(instance->li_file), instance->li_line); +} + +static int +witness_output(const char *fmt, ...) +{ + va_list ap; + int ret; + + va_start(ap, fmt); + ret = witness_voutput(fmt, ap); + va_end(ap); + return (ret); +} + +static int +witness_voutput(const char *fmt, va_list ap) +{ + int ret; + + ret = 0; + switch (witness_channel) { + case WITNESS_CONSOLE: + ret = db_vprintf(fmt, ap); + break; + case WITNESS_LOG: + log(LOG_NOTICE, fmt, ap); + break; + case WITNESS_NONE: + break; + } + return (ret); +} + +#ifdef DDB +static int +witness_thread_has_locks(struct proc *p) +{ + + if (p->p_sleeplocks == NULL) + return (0); + return (p->p_sleeplocks->ll_count != 0); +} + +static int +witness_process_has_locks(struct process *pr) +{ + struct proc *p; + + TAILQ_FOREACH(p, &pr->ps_threads, p_thr_link) { + if (witness_thread_has_locks(p)) + return (1); + } + return (0); +} +#endif + +int +witness_list_locks(struct lock_list_entry **lock_list, + int (*prnt)(const char *fmt, ...)) +{ + struct lock_list_entry *lle; + int i, nheld; + + nheld = 0; + for (lle = *lock_list; lle != NULL; lle = lle->ll_next) + for (i = lle->ll_count - 1; i >= 0; i--) { + witness_list_lock(&lle->ll_children[i], prnt); + nheld++; + } + return (nheld); +} + +/* + * This is a bit risky at best. We call this function when we have timed + * out acquiring a spin lock, and we assume that the other CPU is stuck + * with this lock held. So, we go groveling around in the other CPU's + * per-cpu data to try to find the lock instance for this spin lock to + * see when it was last acquired. + */ +void +witness_display_spinlock(struct lock_object *lock, struct proc *owner, + int (*prnt)(const char *fmt, ...)) +{ + struct lock_instance *instance; + + if (owner->p_stat != SONPROC) + return; + instance = find_instance( + witness_cpu[owner->p_cpu->ci_cpuid].wc_spinlocks, lock); + if (instance != NULL) + witness_list_lock(instance, prnt); +} + +void +witness_save(struct lock_object *lock, const char **filep, int *linep) +{ + struct lock_list_entry *lock_list; + struct lock_instance *instance; + struct lock_class *class; + + KASSERTMSG(witness_cold == 0, "%s: witness_cold", __func__); + if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) + return; + class = LOCK_CLASS(lock); + if (class->lc_flags & LC_SLEEPLOCK) + lock_list = curproc->p_sleeplocks; + else { + if (witness_skipspin) + return; + lock_list = witness_cpu[cpu_number()].wc_spinlocks; + } + instance = find_instance(lock_list, lock); + if (instance == NULL) { + panic("%s: lock (%s) %s not locked", __func__, + class->lc_name, lock->lo_name); + return; + } + *filep = instance->li_file; + *linep = instance->li_line; +} + +void +witness_restore(struct lock_object *lock, const char *file, int line) +{ + struct lock_list_entry *lock_list; + struct lock_instance *instance; + struct lock_class *class; + + KASSERTMSG(witness_cold == 0, "%s: witness_cold", __func__); + if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) + return; + class = LOCK_CLASS(lock); + if (class->lc_flags & LC_SLEEPLOCK) + lock_list = curproc->p_sleeplocks; + else { + if (witness_skipspin) + return; + lock_list = witness_cpu[cpu_number()].wc_spinlocks; + } + instance = find_instance(lock_list, lock); + if (instance == NULL) + panic("%s: lock (%s) %s not locked", __func__, + class->lc_name, lock->lo_name); + lock->lo_witness->w_file = file; + lock->lo_witness->w_line = line; + if (instance == NULL) + return; + instance->li_file = file; + instance->li_line = line; +} + +void +witness_assert(const struct lock_object *lock, int flags, const char *file, + int line) +{ +#ifdef INVARIANT_SUPPORT + struct lock_instance *instance; + struct lock_class *class; + + if (lock->lo_witness == NULL || witness_watch < 1 || panicstr != NULL) + return; + class = LOCK_CLASS(lock); + if ((class->lc_flags & LC_SLEEPLOCK) != 0) + instance = find_instance(curproc->p_sleeplocks, lock); + else if ((class->lc_flags & LC_SPINLOCK) != 0) + instance = find_instance( + witness_cpu[cpu_number()].wc_spinlocks, lock); + else { + panic("Lock (%s) %s is not sleep or spin!", + class->lc_name, lock->lo_name); + return; + } + switch (flags) { + case LA_UNLOCKED: + if (instance != NULL) + panic("Lock (%s) %s locked @ %s:%d.", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + break; + case LA_LOCKED: + case LA_LOCKED | LA_RECURSED: + case LA_LOCKED | LA_NOTRECURSED: + case LA_SLOCKED: + case LA_SLOCKED | LA_RECURSED: + case LA_SLOCKED | LA_NOTRECURSED: + case LA_XLOCKED: + case LA_XLOCKED | LA_RECURSED: + case LA_XLOCKED | LA_NOTRECURSED: + if (instance == NULL) { + panic("Lock (%s) %s not locked @ %s:%d.", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + break; + } + if ((flags & LA_XLOCKED) != 0 && + (instance->li_flags & LI_EXCLUSIVE) == 0) + panic( + "Lock (%s) %s not exclusively locked @ %s:%d.", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + if ((flags & LA_SLOCKED) != 0 && + (instance->li_flags & LI_EXCLUSIVE) != 0) + panic( + "Lock (%s) %s exclusively locked @ %s:%d.", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + if ((flags & LA_RECURSED) != 0 && + (instance->li_flags & LI_RECURSEMASK) == 0) + panic("Lock (%s) %s not recursed @ %s:%d.", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + if ((flags & LA_NOTRECURSED) != 0 && + (instance->li_flags & LI_RECURSEMASK) != 0) + panic("Lock (%s) %s recursed @ %s:%d.", + class->lc_name, lock->lo_name, + fixup_filename(file), line); + break; + default: + panic("Invalid lock assertion at %s:%d.", + fixup_filename(file), line); + + } +#endif /* INVARIANT_SUPPORT */ +} + +static void +witness_setflag(struct lock_object *lock, int flag, int set) +{ + struct lock_list_entry *lock_list; + struct lock_instance *instance; + struct lock_class *class; + + if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL) + return; + class = LOCK_CLASS(lock); + if (class->lc_flags & LC_SLEEPLOCK) + lock_list = curproc->p_sleeplocks; + else { + if (witness_skipspin) + return; + lock_list = witness_cpu[cpu_number()].wc_spinlocks; + } + instance = find_instance(lock_list, lock); + if (instance == NULL) { + panic("%s: lock (%s) %s not locked", __func__, + class->lc_name, lock->lo_name); + return; + } + + if (set) + instance->li_flags |= flag; + else + instance->li_flags &= ~flag; +} + +void +witness_norelease(struct lock_object *lock) +{ + + witness_setflag(lock, LI_NORELEASE, 1); +} + +void +witness_releaseok(struct lock_object *lock) +{ + + witness_setflag(lock, LI_NORELEASE, 0); +} + +#ifdef DDB +static void +witness_ddb_list(struct proc *p) +{ + struct witness_cpu *wc = &witness_cpu[cpu_number()]; + + KASSERTMSG(witness_cold == 0, "%s: witness_cold", __func__); + KASSERTMSG(db_is_active, "%s: not in the debugger", __func__); + + if (witness_watch < 1) + return; + + witness_list_locks(&p->p_sleeplocks, db_printf); + + /* + * We only handle spinlocks if td == curproc. This is somewhat broken + * if td is currently executing on some other CPU and holds spin locks + * as we won't display those locks. If we had a MI way of getting + * the per-cpu data for a given cpu then we could use + * td->td_oncpu to get the list of spinlocks for this thread + * and "fix" this. + * + * That still wouldn't really fix this unless we locked the scheduler + * lock or stopped the other CPU to make sure it wasn't changing the + * list out from under us. It is probably best to just not try to + * handle threads on other CPU's for now. + */ + if (p == curproc && wc->wc_spinlocks != NULL) + witness_list_locks(&wc->wc_spinlocks, db_printf); +} + +void +db_witness_list(db_expr_t addr, int have_addr, db_expr_t count, char *modif) +{ + struct proc *p; + + if (have_addr) + p = (struct proc *)addr; + else + p = curproc; + witness_ddb_list(p); +} + +void +db_witness_list_all(db_expr_t addr, int have_addr, db_expr_t count, char *modif) +{ + struct process *pr; + struct proc *p; + + /* + * It would be nice to list only threads and processes that actually + * held sleep locks, but that information is currently not exported + * by WITNESS. + */ + LIST_FOREACH(pr, &allprocess, ps_list) { + if (!witness_process_has_locks(pr)) + continue; + TAILQ_FOREACH(p, &pr->ps_threads, p_thr_link) { + if (!witness_thread_has_locks(p)) + continue; + db_printf("Process %d (%s) thread %p (%d)\n", + pr->ps_pid, pr->ps_comm, p, p->p_tid); + witness_ddb_list(p); + } + } +} + +void +witness_print_badstacks(void) +{ + static struct witness tmp_w1, tmp_w2; + static struct witness_lock_order_data tmp_data1, tmp_data2; + struct witness_lock_order_data *data1, *data2; + struct witness *w1, *w2; + u_int w_rmatrix1, w_rmatrix2; + int error, generation, i, j; + + if (witness_watch < 1) { + db_printf("witness watch is disabled\n"); + return; + } + if (witness_cold) { + db_printf("witness is cold\n"); + return; + } + error = 0; + + memset(&tmp_w1, 0, sizeof(tmp_w1)); + memset(&tmp_w2, 0, sizeof(tmp_w2)); + memset(&tmp_data1, 0, sizeof(tmp_data1)); + memset(&tmp_data2, 0, sizeof(tmp_data2)); + +restart: + mtx_enter(&w_mtx); + generation = w_generation; + mtx_leave(&w_mtx); + db_printf("Number of known direct relationships is %d\n", + w_lohash.wloh_count); + for (i = 1; i < w_max_used_index; i++) { + mtx_enter(&w_mtx); + if (generation != w_generation) { + mtx_leave(&w_mtx); + + /* The graph has changed, try again. */ + db_printf("Lock graph changed, restarting trace.\n"); + goto restart; + } + + w1 = &w_data[i]; + if (w1->w_reversed == 0) { + mtx_leave(&w_mtx); + continue; + } + + /* Copy w1 locally so we can release the spin lock. */ + tmp_w1 = *w1; + mtx_leave(&w_mtx); + + if (tmp_w1.w_reversed == 0) + continue; + for (j = 1; j < w_max_used_index; j++) { + if ((w_rmatrix[i][j] & WITNESS_REVERSAL) == 0 || i > j) + continue; + + mtx_enter(&w_mtx); + if (generation != w_generation) { + mtx_leave(&w_mtx); + + /* The graph has changed, try again. */ + db_printf("Lock graph changed, " + "restarting trace.\n"); + goto restart; + } + + w2 = &w_data[j]; + data1 = witness_lock_order_get(w1, w2); + data2 = witness_lock_order_get(w2, w1); + + /* + * Copy information locally so we can release the + * spin lock. + */ + tmp_w2 = *w2; + w_rmatrix1 = (unsigned int)w_rmatrix[i][j]; + w_rmatrix2 = (unsigned int)w_rmatrix[j][i]; + + if (data1) + tmp_data1.wlod_stack = data1->wlod_stack; + if (data2 && data2 != data1) + tmp_data2.wlod_stack = data2->wlod_stack; + mtx_leave(&w_mtx); + + db_printf("\nLock order reversal between \"%s\"(%s) " + "and \"%s\"(%s)!\n", + tmp_w1.w_type->lt_name, tmp_w1.w_class->lc_name, + tmp_w2.w_type->lt_name, tmp_w2.w_class->lc_name); + if (data1) { + db_printf("Lock order \"%s\"(%s) -> \"%s\"(%s) " + "first seen at:\n", + tmp_w1.w_type->lt_name, + tmp_w1.w_class->lc_name, + tmp_w2.w_type->lt_name, + tmp_w2.w_class->lc_name); + db_print_stack_trace(&tmp_data1.wlod_stack); + db_printf("\n"); + } + if (data2 && data2 != data1) { + db_printf("Lock order \"%s\"(%s) -> \"%s\"(%s) " + "first seen at:\n", + tmp_w2.w_type->lt_name, + tmp_w2.w_class->lc_name, + tmp_w1.w_type->lt_name, + tmp_w1.w_class->lc_name); + db_print_stack_trace(&tmp_data2.wlod_stack); + db_printf("\n"); + } + } + } + mtx_enter(&w_mtx); + if (generation != w_generation) { + mtx_leave(&w_mtx); + + /* + * The graph changed while we were printing stack data, + * try again. + */ + db_printf("Lock graph changed, restarting trace.\n"); + goto restart; + } + mtx_leave(&w_mtx); +} + +void +db_witness_display(db_expr_t addr, int have_addr, db_expr_t count, char *modif) +{ + switch (modif[0]) { + case 'b': + witness_print_badstacks(); + break; + default: + witness_ddb_display(db_printf); + break; + } +} +#endif + +void +db_witness_print_fullgraph(void) +{ + struct witness *w; + int error; + + if (witness_watch < 1) { + db_printf("witness watch is disabled\n"); + return; + } + if (witness_cold) { + db_printf("witness is cold\n"); + return; + } + error = 0; + + mtx_enter(&w_mtx); + SIMPLEQ_FOREACH(w, &w_all, w_list) + w->w_displayed = 0; + SIMPLEQ_FOREACH(w, &w_all, w_list) + db_witness_add_fullgraph(w); + mtx_leave(&w_mtx); +} + +static void +db_witness_add_fullgraph(struct witness *w) +{ + int i; + + if (w->w_displayed != 0 || (w->w_file == NULL && w->w_line == 0)) + return; + w->w_displayed = 1; + + WITNESS_INDEX_ASSERT(w->w_index); + for (i = 1; i <= w_max_used_index; i++) { + if (w_rmatrix[w->w_index][i] & WITNESS_PARENT) { + db_printf("\"%s\",\"%s\"\n", w->w_type->lt_name, + w_data[i].w_type->lt_name); + db_witness_add_fullgraph(&w_data[i]); + } + } +} + +/* + * A simple hash function. Takes a key pointer and a key size. If size == 0, + * interprets the key as a string and reads until the null + * terminator. Otherwise, reads the first size bytes. Returns an unsigned 32-bit + * hash value computed from the key. + */ +static uint32_t +witness_hash_djb2(const uint8_t *key, uint32_t size) +{ + unsigned int hash = 5381; + int i; + + /* hash = hash * 33 + key[i] */ + if (size) + for (i = 0; i < size; i++) + hash = ((hash << 5) + hash) + (unsigned int)key[i]; + else + for (i = 0; key[i] != 0; i++) + hash = ((hash << 5) + hash) + (unsigned int)key[i]; + + return (hash); +} + + +/* + * Initializes the two witness hash tables. Called exactly once from + * witness_initialize(). + */ +static void +witness_init_hash_tables(void) +{ + int i; + + KASSERT(witness_cold); + + /* Initialize the hash tables. */ + for (i = 0; i < WITNESS_HASH_SIZE; i++) + w_hash.wh_array[i] = NULL; + + w_hash.wh_size = WITNESS_HASH_SIZE; + w_hash.wh_count = 0; + + /* Initialize the lock order data hash. */ + w_lofree = NULL; + for (i = 0; i < WITNESS_LO_DATA_COUNT; i++) { + memset(&w_lodata[i], 0, sizeof(w_lodata[i])); + w_lodata[i].wlod_next = w_lofree; + w_lofree = &w_lodata[i]; + } + w_lohash.wloh_size = WITNESS_LO_HASH_SIZE; + w_lohash.wloh_count = 0; + for (i = 0; i < WITNESS_LO_HASH_SIZE; i++) + w_lohash.wloh_array[i] = NULL; +} + +static struct witness * +witness_hash_get(struct lock_type *type, const char *subtype) +{ + struct witness *w; + uint32_t hash; + + KASSERT(type != NULL); + if (witness_cold == 0) + MUTEX_ASSERT_LOCKED(&w_mtx); + hash = (uint32_t)((uintptr_t)type ^ (uintptr_t)subtype) % + w_hash.wh_size; + w = w_hash.wh_array[hash]; + while (w != NULL) { + if (w->w_type == type && w->w_subtype == subtype) + goto out; + w = w->w_hash_next; + } + +out: + return (w); +} + +static void +witness_hash_put(struct witness *w) +{ + uint32_t hash; + + KASSERT(w != NULL); + KASSERT(w->w_type != NULL); + if (witness_cold == 0) + MUTEX_ASSERT_LOCKED(&w_mtx); + KASSERTMSG(witness_hash_get(w->w_type, w->w_subtype) == NULL, + "%s: trying to add a hash entry that already exists!", __func__); + KASSERTMSG(w->w_hash_next == NULL, + "%s: w->w_hash_next != NULL", __func__); + + hash = (uint32_t)((uintptr_t)w->w_type ^ (uintptr_t)w->w_subtype) % + w_hash.wh_size; + w->w_hash_next = w_hash.wh_array[hash]; + w_hash.wh_array[hash] = w; + w_hash.wh_count++; +} + + +static struct witness_lock_order_data * +witness_lock_order_get(struct witness *parent, struct witness *child) +{ + struct witness_lock_order_data *data = NULL; + struct witness_lock_order_key key; + unsigned int hash; + + KASSERT(parent != NULL && child != NULL); + key.from = parent->w_index; + key.to = child->w_index; + WITNESS_INDEX_ASSERT(key.from); + WITNESS_INDEX_ASSERT(key.to); + if ((w_rmatrix[parent->w_index][child->w_index] + & WITNESS_LOCK_ORDER_KNOWN) == 0) + goto out; + + hash = witness_hash_djb2((const char*)&key, + sizeof(key)) % w_lohash.wloh_size; + data = w_lohash.wloh_array[hash]; + while (data != NULL) { + if (witness_lock_order_key_equal(&data->wlod_key, &key)) + break; + data = data->wlod_next; + } + +out: + return (data); +} + +/* + * Verify that parent and child have a known relationship, are not the same, + * and child is actually a child of parent. This is done without w_mtx + * to avoid contention in the common case. + */ +static int +witness_lock_order_check(struct witness *parent, struct witness *child) +{ + + if (parent != child && + w_rmatrix[parent->w_index][child->w_index] + & WITNESS_LOCK_ORDER_KNOWN && + isitmychild(parent, child)) + return (1); + + return (0); +} + +static int +witness_lock_order_add(struct witness *parent, struct witness *child) +{ + struct witness_lock_order_data *data = NULL; + struct witness_lock_order_key key; + unsigned int hash; + + KASSERT(parent != NULL && child != NULL); + key.from = parent->w_index; + key.to = child->w_index; + WITNESS_INDEX_ASSERT(key.from); + WITNESS_INDEX_ASSERT(key.to); + if (w_rmatrix[parent->w_index][child->w_index] + & WITNESS_LOCK_ORDER_KNOWN) + return (1); + + hash = witness_hash_djb2((const char*)&key, + sizeof(key)) % w_lohash.wloh_size; + w_rmatrix[parent->w_index][child->w_index] |= WITNESS_LOCK_ORDER_KNOWN; + data = w_lofree; + if (data == NULL) + return (0); + w_lofree = data->wlod_next; + data->wlod_next = w_lohash.wloh_array[hash]; + data->wlod_key = key; + w_lohash.wloh_array[hash] = data; + w_lohash.wloh_count++; + db_save_stack_trace(&data->wlod_stack); + return (1); +} + +/* Call this whenever the structure of the witness graph changes. */ +static void +witness_increment_graph_generation(void) +{ + + if (witness_cold == 0) + MUTEX_ASSERT_LOCKED(&w_mtx); + w_generation++; +} + +static void +witness_debugger(int cond, const char *msg) +{ + if (!cond) + return; + + Debugger(); +} diff --git a/sys/sys/_lock.h b/sys/sys/_lock.h new file mode 100644 index 00000000000..6db33f07cd0 --- /dev/null +++ b/sys/sys/_lock.h @@ -0,0 +1,80 @@ +/* $OpenBSD: _lock.h,v 1.1 2017/04/20 12:59:36 visa Exp $ */ + +/*- + * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Berkeley Software Design Inc's name may not be used to endorse or + * promote products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD: head/sys/sys/_lock.h 179025 2008-05-15 20:10:06Z attilio $ + */ + +#ifndef _SYS__LOCK_H_ +#define _SYS__LOCK_H_ + +#define LO_CLASSFLAGS 0x0000ffff /* Class specific flags. */ +#define LO_INITIALIZED 0x00010000 /* Lock has been initialized. */ +#define LO_WITNESS 0x00020000 /* Should witness monitor this lock. */ +#define LO_QUIET 0x00040000 /* Don't log locking operations. */ +#define LO_RECURSABLE 0x00080000 /* Lock may recurse. */ +#define LO_SLEEPABLE 0x00100000 /* Lock may be held while sleeping. */ +#define LO_UPGRADABLE 0x00200000 /* Lock may be upgraded/downgraded. */ +#define LO_DUPOK 0x00400000 /* Don't check for duplicate acquires */ +#define LO_IS_VNODE 0x00800000 /* Tell WITNESS about a VNODE lock */ +#define LO_CLASSMASK 0x0f000000 /* Class index bitmask. */ +#define LO_NOPROFILE 0x10000000 /* Don't profile this lock */ +#define LO_NEW 0x20000000 /* Don't check for double-init */ + +#define LO_CLASSSHIFT 24 + +enum lock_class_index { + LO_CLASS_KERNEL_LOCK, + LO_CLASS_SCHED_LOCK, + LO_CLASS_MUTEX, + LO_CLASS_RWLOCK, + LO_CLASS_RRWLOCK +}; + +struct lock_object { + struct lock_type *lo_type; + const char *lo_name; /* Individual lock name. */ + struct witness *lo_witness; /* Data for witness. */ + uint32_t lo_flags; +}; + +struct lock_type { + const char *lt_name; +}; + +#ifdef WITNESS +#define LOCK_FL_VARS , const char *file, int line +#define LOCK_FL_ARGS , file, line +#define LOCK_FILE_LINE , __FILE__, __LINE__ +#else +#define LOCK_FL_VARS +#define LOCK_FL_ARGS +#define LOCK_FILE_LINE +#endif + +#endif /* !_SYS__LOCK_H_ */ diff --git a/sys/sys/proc.h b/sys/sys/proc.h index 3b85a967a01..5cb1cc1b9de 100644 --- a/sys/sys/proc.h +++ b/sys/sys/proc.h @@ -1,4 +1,4 @@ -/* $OpenBSD: proc.h,v 1.237 2017/04/13 03:52:25 guenther Exp $ */ +/* $OpenBSD: proc.h,v 1.238 2017/04/20 12:59:36 visa Exp $ */ /* $NetBSD: proc.h,v 1.44 1996/04/22 01:23:21 christos Exp $ */ /*- @@ -273,6 +273,8 @@ struct process { "\024NOBROADCASTKILL" "\025PLEDGE" "\026WXNEEDED") +struct lock_list_entry; + struct proc { TAILQ_ENTRY(proc) p_runq; LIST_ENTRY(proc) p_list; /* List of all threads. */ @@ -348,6 +350,8 @@ struct proc { int p_sicode; /* For core dump/debugger XXX */ u_short p_xstat; /* Exit status for wait; also stop signal. */ + + struct lock_list_entry *p_sleeplocks; }; /* Status values. */ diff --git a/sys/sys/witness.h b/sys/sys/witness.h new file mode 100644 index 00000000000..74862a8f669 --- /dev/null +++ b/sys/sys/witness.h @@ -0,0 +1,178 @@ +/* $OpenBSD: witness.h,v 1.1 2017/04/20 12:59:36 visa Exp $ */ + +/*- + * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Berkeley Software Design Inc's name may not be used to endorse or + * promote products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * from BSDI Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp + * $FreeBSD: head/sys/sys/lock.h 313908 2017-02-18 01:52:10Z mjg $ + */ + +#ifndef _SYS_WITNESS_H_ +#define _SYS_WITNESS_H_ + +#include + +/* + * Lock classes are statically assigned an index into the global lock_classes + * array. Debugging code looks up the lock class for a given lock object + * by indexing the array. + */ +#define LO_CLASSINDEX(lock) \ + ((((lock)->lo_flags) & LO_CLASSMASK) >> LO_CLASSSHIFT) +#define LOCK_CLASS(lock) \ + (lock_classes[LO_CLASSINDEX((lock))]) +#define LOCK_CLASS_MAX \ + (LO_CLASSMASK >> LO_CLASSSHIFT) + +/* + * Option flags passed to lock operations that witness also needs to know + * about or that are generic across all locks. + */ +#define LOP_NEWORDER 0x00000001 /* Define a new lock order. */ +#define LOP_QUIET 0x00000002 /* Don't log locking operations. */ +#define LOP_TRYLOCK 0x00000004 /* Don't check lock order. */ +#define LOP_EXCLUSIVE 0x00000008 /* Exclusive lock. */ +#define LOP_DUPOK 0x00000010 /* Don't check for duplicate acquires */ + +/* Flags passed to witness_assert. */ +#define LA_MASKASSERT 0x000000ff /* Mask for witness defined asserts. */ +#define LA_UNLOCKED 0x00000000 /* Lock is unlocked. */ +#define LA_LOCKED 0x00000001 /* Lock is at least share locked. */ +#define LA_SLOCKED 0x00000002 /* Lock is exactly share locked. */ +#define LA_XLOCKED 0x00000004 /* Lock is exclusively locked. */ +#define LA_RECURSED 0x00000008 /* Lock is recursed. */ +#define LA_NOTRECURSED 0x00000010 /* Lock is not recursed. */ + +#ifdef _KERNEL + +void witness_initialize(void); +void witness_init(struct lock_object *, struct lock_type *); +int witness_defineorder(struct lock_object *, struct lock_object *); +void witness_checkorder(struct lock_object *, int, const char *, int, + struct lock_object *); +void witness_lock(struct lock_object *, int, const char *, int); +void witness_upgrade(struct lock_object *, int, const char *, int); +void witness_downgrade(struct lock_object *, int, const char *, int); +void witness_unlock(struct lock_object *, int, const char *, int); +void witness_save(struct lock_object *, const char **, int *); +void witness_restore(struct lock_object *, const char *, int); +int witness_warn(int, struct lock_object *, const char *, ...); +void witness_assert(const struct lock_object *, int, const char *, int); +void witness_display_spinlock(struct lock_object *, struct proc *, + int (*)(const char *, ...)); +int witness_line(struct lock_object *); +void witness_norelease(struct lock_object *); +void witness_releaseok(struct lock_object *); +const char *witness_file(struct lock_object *); +void witness_thread_exit(struct proc *); + +#ifdef WITNESS + +/* Flags for witness_warn(). */ +#define WARN_KERNELOK 0x01 /* Kernel lock is exempt from this check. */ +#define WARN_PANIC 0x02 /* Panic if check fails. */ +#define WARN_SLEEPOK 0x04 /* Sleepable locks are exempt from check. */ + +#define WITNESS_INITIALIZE() \ + witness_initialize() + +#define WITNESS_INIT(lock, type) \ + witness_init((lock), (type)) + +#define WITNESS_CHECKORDER(lock, flags, file, line, interlock) \ + witness_checkorder((lock), (flags), (file), (line), (interlock)) + +#define WITNESS_DEFINEORDER(lock1, lock2) \ + witness_defineorder((struct lock_object *)(lock1), \ + (struct lock_object *)(lock2)) + +#define WITNESS_LOCK(lock, flags, file, line) \ + witness_lock((lock), (flags), (file), (line)) + +#define WITNESS_UPGRADE(lock, flags, file, line) \ + witness_upgrade((lock), (flags), (file), (line)) + +#define WITNESS_DOWNGRADE(lock, flags, file, line) \ + witness_downgrade((lock), (flags), (file), (line)) + +#define WITNESS_UNLOCK(lock, flags, file, line) \ + witness_unlock((lock), (flags), (file), (line)) + +#define WITNESS_CHECK(flags, lock, fmt, ...) \ + witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) + +#define WITNESS_WARN(flags, lock, fmt, ...) \ + witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) + +#define WITNESS_SAVE_DECL(n) \ + const char * __CONCAT(n, __wf); \ + int __CONCAT(n, __wl) + +#define WITNESS_SAVE(lock, n) \ + witness_save((lock), &__CONCAT(n, __wf), &__CONCAT(n, __wl)) + +#define WITNESS_RESTORE(lock, n) \ + witness_restore((lock), __CONCAT(n, __wf), __CONCAT(n, __wl)) + +#define WITNESS_NORELEASE(lock) \ + witness_norelease(&(lock)->lock_object) + +#define WITNESS_RELEASEOK(lock) \ + witness_releaseok(&(lock)->lock_object) + +#define WITNESS_FILE(lock) \ + witness_file(lock) + +#define WITNESS_LINE(lock) \ + witness_line(lock) + +#define WITNESS_THREAD_EXIT(p) \ + witness_thread_exit((p)) + +#else /* WITNESS */ +#define WITNESS_INITIALIZE() (void)0 +#define WITNESS_INIT(lock, type) (void)0 +#define WITNESS_DEFINEORDER(lock1, lock2) 0 +#define WITNESS_CHECKORDER(lock, flags, file, line, interlock) (void)0 +#define WITNESS_LOCK(lock, flags, file, line) (void)0 +#define WITNESS_UPGRADE(lock, flags, file, line) (void)0 +#define WITNESS_DOWNGRADE(lock, flags, file, line) (void)0 +#define WITNESS_UNLOCK(lock, flags, file, line) (void)0 +#define WITNESS_CHECK(flags, lock, fmt, ...) 0 +#define WITNESS_WARN(flags, lock, fmt, ...) (void)0 +#define WITNESS_SAVE_DECL(n) (void)0 +#define WITNESS_SAVE(lock, n) (void)0 +#define WITNESS_RESTORE(lock, n) (void)0 +#define WITNESS_NORELEASE(lock) (void)0 +#define WITNESS_RELEASEOK(lock) (void)0 +#define WITNESS_THREAD_EXIT(p) (void)0 +#define WITNESS_FILE(lock) ("?") +#define WITNESS_LINE(lock) (0) +#endif /* WITNESS */ + +#endif /* _KERNEL */ +#endif /* _SYS_WITNESS_H_ */