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Commit 5375b708 authored by HATAYAMA Daisuke's avatar HATAYAMA Daisuke Committed by Linus Torvalds
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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: default avatarHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: default avatarBaoquan He <bhe@redhat.com>
Tested-by: default avatarHidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Reviewed-by: default avatarMasami 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus 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;