Commit 4302fbc8 authored Jul 26, 2011 by Hugh Dickins Committed by Linus Torvalds Jul 26, 2011

panic: panic=-1 for immediate reboot



When a 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: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Olaf Hering <olaf@aepfle.de>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 3f0fb4e8

Documentation/kernel-parameters.txt

+3 −1

Original line number	Diff line number	Diff line
		@@ -1846,7 +1846,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
		See Documentation/sound/oss/oss-parameters.txt

		panic= [KNL] Kernel behaviour on panic: delay <timeout>
		seconds before rebooting
		timeout > 0: seconds before rebooting
		timeout = 0: wait forever
		timeout < 0: reboot immediately
		Format: <timeout>

		parkbd.port= [HW] Parallel port number the keyboard adapter is

kernel/panic.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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

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