Commit 5375b708 authored Jun 30, 2015 by HATAYAMA Daisuke Committed by Linus Torvalds Jun 30, 2015

kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path



Commit f06e5153 ("kernel/panic.c: add "crash_kexec_post_notifiers"
option for kdump after panic_notifers") introduced
"crash_kexec_post_notifiers" kernel boot option, which toggles wheather
panic() calls crash_kexec() before panic_notifiers and dump kmsg or after.

The problem is that the commit overlooks panic_on_oops kernel boot option.
 If it is enabled, crash_kexec() is called directly without going through
panic() in oops path.

To fix this issue, this patch adds a check to "crash_kexec_post_notifiers"
in the condition of kexec_should_crash().

Also, put a comment in kexec_should_crash() to explain not obvious things
on this patch.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: Baoquan He <bhe@redhat.com>
Tested-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent f45d85ff

include/linux/kernel.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -439,6 +439,9 @@ extern int panic_on_unrecovered_nmi;
		extern int panic_on_io_nmi;
		extern int panic_on_warn;
		extern int sysctl_panic_on_stackoverflow;

		extern bool crash_kexec_post_notifiers;

		/*
		* Only to be used by arch init code. If the user over-wrote the default
		* CONFIG_PANIC_TIMEOUT, honor it.

kernel/kexec.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -84,6 +84,17 @@ struct resource crashk_low_res = {

		int kexec_should_crash(struct task_struct *p)
		{
		/*
		* If crash_kexec_post_notifiers is enabled, don't run
		* crash_kexec() here yet, which must be run after panic
		* notifiers in panic().
		*/
		if (crash_kexec_post_notifiers)
		return 0;
		/*
		* There are 4 panic() calls in do_exit() path, each of which
		* corresponds to each of these 4 conditions.
		*/
		if (in_interrupt() \|\| !p->pid \|\| is_global_init(p) \|\| panic_on_oops)
		return 1;
		return 0;

kernel/panic.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -32,7 +32,7 @@ static unsigned long tainted_mask;
		static int pause_on_oops;
		static int pause_on_oops_flag;
		static DEFINE_SPINLOCK(pause_on_oops_lock);
		static bool crash_kexec_post_notifiers;
		bool crash_kexec_post_notifiers;
		int panic_on_warn __read_mostly;

		int panic_timeout = CONFIG_PANIC_TIMEOUT;

Admin message