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

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Message-ID: <20231220131534.4.Id3a9c7ec2d7d83e4080da6f8662ba2226b40543f@changeid>
Date: Wed, 20 Dec 2023 13:15:37 -0800
From: Douglas Anderson <dianders@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Petr Mladek <pmladek@...e.com>,
	Li Zhe <lizhe.67@...edance.com>,
	Pingfan Liu <kernelfans@...il.com>,
	John Ogness <john.ogness@...utronix.de>,
	Lecopzer Chen <lecopzer.chen@...iatek.com>,
	Douglas Anderson <dianders@...omium.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 4/4] watchdog: If panicking and we dumped everything, don't re-enable dumping

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@...omium.org>
---

 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