[PATCH 1/2] panic: panic=-1 for immediate reboot

[Mandeep Singh Baines <msb@chromium.org>]

From: Hugh Dickins <hughd@chromium.org>

When kernel BUG or oops occurs, ChromeOS intends to panic and immediately
reboot, with stacktrace and other messages preserved in RAM across reboot.
But the longer we delay, the more likely the user is to poweroff and lose
the info.

panic_timeout (seconds before rebooting) is set by panic= boot option
or sysctl or /proc/sys/kernel/panic; but 0 means wait forever, so at
present we have to delay at least 1 second.

Let a negative number mean reboot immediately (with the small cosmetic
benefit of suppressing that newline-less "Rebooting in %d seconds.."
message).

Signed-off-by: Hugh Dickins <hughd@chromium.org>
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hughd@chromium.org>
Cc: Olaf Hering <olaf@aepfle.de>
---
 kernel/panic.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index 6923167..d7bb697 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -119,6 +119,8 @@ NORET_TYPE void panic(const char * fmt, ...)
 			}
 			mdelay(PANIC_TIMER_STEP);
 		}
+	}
+	if (panic_timeout != 0) {
 		/*
 		 * This will not be a clean reboot, with everything
 		 * shutting down.  But if there is a chance of
-- 
1.7.3.1