panic: call panic handlers before kmsg_dump

Since the panic handlers may produce additional information (via printk)
for the kernel log, it should be reported as part of the panic output
saved by kmsg_dump().  Without this re-ordering, nothing that adds
information to a panic will show up in pstore's view when kmsg_dump runs,
and is therefore not visible to crash reporting tools that examine pstore
output.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Vikram Mulukutla <markivx@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/kernel/panic.c b/kernel/panic.c
index 801864600514..b6c482ccc5db 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -123,10 +123,14 @@ void panic(const char *fmt, ...)
          */
         smp_send_stop();
 
-        kmsg_dump(KMSG_DUMP_PANIC);
-
+        /*
+         * Run any panic handlers, including those that might need to
+         * add information to the kmsg dump output.
+         */
         atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
 
+        kmsg_dump(KMSG_DUMP_PANIC);
+
         bust_spinlocks(0);
 
         if (!panic_blink)