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 <[email protected]>
Cc: Anton Vorontsov <[email protected]>
Cc: Colin Cross <[email protected]>
Acked-by: Tony Luck <[email protected]>
Cc: Stephen Boyd <[email protected]>
Cc: Vikram Mulukutla <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rusty Russell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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)