Messages in this thread Patch in this message | | | Date | Wed, 17 Jan 2007 10:13:19 +0100 | From | Ingo Molnar <> | Subject | [patch] fix emergency reboot: call reboot notifier list if possible |
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Subject: [patch] call reboot notifier list when doing an emergency reboot From: Ingo Molnar <mingo@elte.hu>
my laptop (Lenovo T60) hangs during reboot if the shutdown notifiers are not called. So the following command, which on other systems i use as a quick way to reboot into a new kernel:
echo b > /proc/sysrq-trigger
just hangs indefinitely after the kernel prints "Restarting system".
we dont call the reboot notifiers during emergency reboot mainly because it could be called from atomic context and reboot notifiers are a blocking notifier list. But actually the kernel is often perfectly reschedulable in this stage, so we could as well process the reboot_notifier_list.
(furthermore, on -rt kernels this place is preemptable even during SysRq-b)
So just process the reboot notifier list if we are preemptable. This will shut disk caches and chipsets off.
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- kernel/sys.c | 7 +++++++ 1 file changed, 7 insertions(+)
Index: linux/kernel/sys.c =================================================================== --- linux.orig/kernel/sys.c +++ linux/kernel/sys.c @@ -710,6 +710,13 @@ out_unlock: */ void emergency_restart(void) { + /* + * Call the notifier chain if we are not in an + * atomic context: + */ + if (!preempt_count() && !irqs_disabled()) + blocking_notifier_call_chain(&reboot_notifier_list, + SYS_RESTART, NULL); machine_emergency_restart(); } EXPORT_SYMBOL_GPL(emergency_restart); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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