[IA64] dump stack on kernel unaligned warnings

Often the cause of kernel unaligned access warnings is not obvious from just the ip displayed in the warning. This adds the option via proc to dump the stack in addition to the warning. The default is off (just display the 1 line warning). To enable the stack to be shown: echo 1 > /proc/sys/kernel/unaligned-dump-stack Signed-off-by: Doug Chapman <doug.chapman@hp.com> Signed-off-by: Tony Luck <tony.luck@intel.com>

[IA64] dump stack on kernel unaligned warnings
Often the cause of kernel unaligned access warnings is not obvious from just the ip displayed in the warning. This adds the option via proc to dump the stack in addition to the warning. The default is off (just display the 1 line warning). To enable the stack to be shown: echo 1 > /proc/sys/kernel/unaligned-dump-stack Signed-off-by: Doug Chapman <doug.chapman@hp.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Doug Chapman · Tony Luck
1 parent 0773a6cf67
Showing 2 changed files with 14 additions and 1 deletions Side-by-side Diff
arch/ia64/kernel/unaligned.c
kernel/sysctl.c
@@ -59,6 +59,7 @@
  *  (i.e. don't allow attacker to fill up logs with unaligned accesses).
  */
 int no_unaligned_warning;
+int unaligned_dump_stack;
 static int noprint_warning;
  
 /*
  
@@ -1371,9 +1372,12 @@
 			}
 		}
 	} else {
-		if (within_logging_rate_limit())
+		if (within_logging_rate_limit()) {
 			printk(KERN_WARNING "kernel unaligned access to 0x%016lx, ip=0x%016lx\n",
 			       ifa, regs->cr_iip + ipsr->ri);
+			if (unaligned_dump_stack)
+				dump_stack();
+		}
 		set_fs(KERNEL_DS);
 	}
  
@@ -144,6 +144,7 @@
  
 #ifdef CONFIG_IA64
 extern int no_unaligned_warning;
+extern int unaligned_dump_stack;
 #endif
  
 #ifdef CONFIG_RT_MUTEXES
@@ -779,6 +780,14 @@
 		.data		= &no_unaligned_warning,
 		.maxlen		= sizeof (int),
 	 	.mode		= 0644,
+		.proc_handler	= &proc_dointvec,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "unaligned-dump-stack",
+		.data		= &unaligned_dump_stack,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
 		.proc_handler	= &proc_dointvec,
 	},
 #endif
...	...	@@ -59,6 +59,7 @@
59	59	* (i.e. don't allow attacker to fill up logs with unaligned accesses).
60	60	*/
61	61	int no_unaligned_warning;
	62	+int unaligned_dump_stack;
62	63	static int noprint_warning;
63	64
64	65	/*
65	66
...	...	@@ -1371,9 +1372,12 @@
1371	1372	}
1372	1373	}
1373	1374	} else {
1374		- if (within_logging_rate_limit())
	1375	+ if (within_logging_rate_limit()) {
1375	1376	printk(KERN_WARNING "kernel unaligned access to 0x%016lx, ip=0x%016lx\n",
1376	1377	ifa, regs->cr_iip + ipsr->ri);
	1378	+ if (unaligned_dump_stack)
	1379	+ dump_stack();
	1380	+ }
1377	1381	set_fs(KERNEL_DS);
1378	1382	}
1379	1383
...	...	@@ -144,6 +144,7 @@
144	144
145	145	#ifdef CONFIG_IA64
146	146	extern int no_unaligned_warning;
	147	+extern int unaligned_dump_stack;
147	148	#endif
148	149
149	150	#ifdef CONFIG_RT_MUTEXES
...	...	@@ -779,6 +780,14 @@
779	780	.data = &no_unaligned_warning,
780	781	.maxlen = sizeof (int),
781	782	.mode = 0644,
	783	+ .proc_handler = &proc_dointvec,
	784	+ },
	785	+ {
	786	+ .ctl_name = CTL_UNNUMBERED,
	787	+ .procname = "unaligned-dump-stack",
	788	+ .data = &unaligned_dump_stack,
	789	+ .maxlen = sizeof (int),
	790	+ .mode = 0644,
782	791	.proc_handler = &proc_dointvec,
783	792	},
784	793	#endif