sysfs: crash debugging

Print the name of the last-accessed sysfs file when we oops, to help track
down oopses which occur in sysfs store/read handlers.  Because these oopses
tend to not leave any trace of the offending code in the stack traces.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 086cc8118e39..96a5db7da8a7 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -13,6 +13,7 @@
 #include <linux/kexec.h>
 #include <linux/bug.h>
 #include <linux/nmi.h>
+#include <linux/sysfs.h>
 
 #include <asm/stacktrace.h>
 
@@ -489,6 +490,7 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err)
         printk("DEBUG_PAGEALLOC");
 #endif
         printk("\n");
+        sysfs_printk_last_file();
         if (notify_die(DIE_OOPS, str, regs, err,
                         current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
                 return 1;