[PATCH 4/4] watchdog: If panicking and we dumped everything, don't re-enable dumping

From: Douglas Anderson
Date: Wed Dec 20 2023 - 16:18:07 EST


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.

Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---

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

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 11f9577accca..81a8862295d6 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -192,7 +192,8 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)

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_timer_fn(struct hrtimer *hrtimer)

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);
--
2.43.0.472.g3155946c3a-goog