+ watchdog-if-panicking-and-we-dumped-everything-dont-re-enable-dumping.patch added to mm-nonmm-unstable branch

+ watchdog-if-panicking-and-we-dumped-everything-dont-re-enable-dumping.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: watchdog: if panicking and we dumped everything, don't re-enable dumping
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     watchdog-if-panicking-and-we-dumped-everything-dont-re-enable-dumping.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/watchdog-if-panicking-and-we-dumped-everything-dont-re-enable-dumping.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Douglas Anderson <dianders@chromium.org>
Subject: watchdog: if panicking and we dumped everything, don't re-enable dumping
Date: Wed, 20 Dec 2023 13:15:37 -0800

If, as part of handling a hardlockup or softlockup, we've already dumped
all CPUs and we're just about to panic, don't reenable dumping and give
some other CPU a chance to hop in there and add some confusing logs right
as the panic is happening.

Link: https://lkml.kernel.org/r/20231220131534.4.Id3a9c7ec2d7d83e4080da6f8662ba2226b40543f@changeid
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/watchdog.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/kernel/watchdog.c~watchdog-if-panicking-and-we-dumped-everything-dont-re-enable-dumping
+++ a/kernel/watchdog.c
@@ -192,7 +192,8 @@ void watchdog_hardlockup_check(unsigned
 
 		if (sysctl_hardlockup_all_cpu_backtrace) {
 			trigger_allbutcpu_cpu_backtrace(cpu);
-			clear_bit_unlock(0, &hard_lockup_nmi_warn);
+			if (!hardlockup_panic)
+				clear_bit_unlock(0, &hard_lockup_nmi_warn);
 		}
 
 		if (hardlockup_panic)
@@ -548,7 +549,8 @@ static enum hrtimer_restart watchdog_tim
 
 		if (softlockup_all_cpu_backtrace) {
 			trigger_allbutcpu_cpu_backtrace(smp_processor_id());
-			clear_bit_unlock(0, &soft_lockup_nmi_warn);
+			if (!softlockup_panic)
+				clear_bit_unlock(0, &soft_lockup_nmi_warn);
 		}
 
 		add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
_

Patches currently in -mm which might be from dianders@chromium.org are

watchdog-hardlockup-adopt-softlockup-logic-avoiding-double-dumps.patch
watchdog-softlockup-use-printk_cpu_sync_get_irqsave-to-serialize-reporting.patch
watchdog-hardlockup-use-printk_cpu_sync_get_irqsave-to-serialize-reporting.patch
watchdog-if-panicking-and-we-dumped-everything-dont-re-enable-dumping.patch