Show uvm_fault and trace when typing show panic on a page fault'd kernel

Currently there is only support for amd64, if this change settles
I will add support for the rest of the architectures.

OK kettenis@.

diff --git a/sys/arch/amd64/amd64/trap.c b/sys/arch/amd64/amd64/trap.c
index 96565bd..47b3bee 100644 (file)
--- a/sys/arch/amd64/amd64/trap.c
+++ b/sys/arch/amd64/amd64/trap.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: trap.c,v 1.62 2017/10/14 04:44:43 jsg Exp $   */
+/*     $OpenBSD: trap.c,v 1.63 2018/01/05 11:10:25 pirofti Exp $       */
 /*     $NetBSD: trap.c,v 1.2 2003/05/04 23:51:56 fvdl Exp $    */
 
 /*-
@@ -380,12 +380,16 @@ faultcommon:
                }
 
                if (type == T_PAGEFLT) {
+                       static char faultbuf[512];
                        if (pcb->pcb_onfault != 0) {
                                KERNEL_UNLOCK();
                                goto copyfault;
                        }
-                       printf("uvm_fault(%p, 0x%lx, 0, %d) -> %x\n",
+                       snprintf(faultbuf, sizeof faultbuf,
+                           "uvm_fault(%p, 0x%lx, 0, %d) -> %x",
                            map, fa, ftype, error);
+                       printf("%s\n", faultbuf);
+                       faultstr = faultbuf;
                        goto we_re_toast;
                }
 

diff --git a/sys/ddb/db_command.c b/sys/ddb/db_command.c
index cd4cd40..a275023 100644 (file)
--- a/sys/ddb/db_command.c
+++ b/sys/ddb/db_command.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: db_command.c,v 1.82 2017/12/13 08:34:04 mpi Exp $     */
+/*     $OpenBSD: db_command.c,v 1.83 2018/01/05 11:10:25 pirofti Exp $ */
 /*     $NetBSD: db_command.c,v 1.20 1996/03/30 22:30:05 christos Exp $ */
 
 /*
@@ -51,6 +51,7 @@
 #include <ddb/db_watch.h>
 #include <ddb/db_run.h>
 #include <ddb/db_sym.h>
+#include <ddb/db_var.h>
 #include <ddb/db_variables.h>
 #include <ddb/db_interface.h>
 #include <ddb/db_extern.h>
@@ -491,6 +492,11 @@ db_show_panic_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
 {
        if (panicstr)
                db_printf("%s\n", panicstr);
+       else if (faultstr) {
+               db_printf("kernel page fault\n");
+               db_printf("%s\n", faultstr);
+               db_stack_trace_print(addr, have_addr, 1, modif, db_printf);
+       }
        else
                db_printf("the kernel did not panic\n");        /* yet */
 }

diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c
index bb527c5..3572e80 100644 (file)
--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: subr_prf.c,v 1.92 2017/12/30 20:47:00 guenther Exp $  */
+/*     $OpenBSD: subr_prf.c,v 1.93 2018/01/05 11:10:25 pirofti Exp $   */
 /*     $NetBSD: subr_prf.c,v 1.45 1997/10/24 18:14:25 chuck Exp $      */
 
 /*-
@@ -99,6 +99,7 @@ struct mutex kprintf_mutex =
 extern int log_open;   /* subr_log: is /dev/klog open? */
 const  char *panicstr; /* arg to first call to panic (used as a flag
                           to indicate that panic has already been called). */
+const  char *faultstr; /* page fault string */
 #ifdef DDB
 /*
  * Enter ddb on panic.

diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 04326d9..5fa3b80 100644 (file)
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: systm.h,v 1.136 2017/12/14 00:41:58 dlg Exp $ */
+/*     $OpenBSD: systm.h,v 1.137 2018/01/05 11:10:25 pirofti Exp $     */
 /*     $NetBSD: systm.h,v 1.50 1996/06/09 04:55:09 briggs Exp $        */
 
 /*-
@@ -72,6 +72,7 @@
  */
 extern int securelevel;                /* system security level */
 extern const char *panicstr;   /* panic message */
+extern const char *faultstr;   /* fault message */
 extern const char version[];           /* system version */
 extern const char copyright[]; /* system copyright */
 extern const char ostype[];