From: pirofti <pirofti@openbsd.org>
Date: Fri, 5 Jan 2018 11:10:25 +0000 (+0000)
Subject: Show uvm_fault and trace when typing show panic on a page fault'd kernel
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=c1088d887145f4cbb30e3a16e1cf9081a6cd9e1b;p=openbsd

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 96565bd738d..47b3bee5128 100644
--- 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 cd4cd40b714..a275023dc58 100644
--- 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 bb527c5ba15..3572e809d09 100644
--- 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 04326d9db38..5fa3b80b177 100644
--- 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[];