linux-kernel - [PATCH] exit: skip IRQ disabled warning during power off

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Message-Id: <20250403-exit-v1-1-8e9266bfc4b7@debian.org>
Date: Thu, 03 Apr 2025 11:01:29 -0700
From: Breno Leitao <leitao@...ian.org>
To: akpm@...ux-foundation.org, brauner@...nel.org
Cc: linux-kernel@...r.kernel.org, joel.granados@...nel.org, 
 kernel-team@...a.com, oleg@...hat.com, mjguzik@...il.com, 
 Breno Leitao <leitao@...ian.org>
Subject: [PATCH] exit: skip IRQ disabled warning during power off

When the system is shutting down due to pid 1 exiting, which is common
on virtual machines, a warning message is printed.

	WARNING: CPU: 0 PID: 1 at kernel/exit.c:897 do_exit+0x7e3/0xab0

This occurs because do_exit() is called after kernel_power_off(), which
disables interrupts. native_machine_shutdown() expliclty disable
interrupt to avoid receiving the timer interrupt, forcing scheduler load
balance during the power off phase.

This is the simplified code path:

	kernel_power_off()
	  - native_machine_shutdown()
	  	- local_irq_disable()
	do_exit()

Modify the warning condition in do_exit() to only trigger the warning if
the system is not powering off, since it is expected to have the irq
disabled in that case.

Signed-off-by: Breno Leitao <leitao@...ian.org>
---
 kernel/exit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index 3485e5fc499e4..97ec4f8bfd98f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -878,7 +878,7 @@ void __noreturn do_exit(long code)
 	struct task_struct *tsk = current;
 	int group_dead;

-	WARN_ON(irqs_disabled());
+	WARN_ON(irqs_disabled() && system_state != SYSTEM_POWER_OFF);

 	synchronize_group_exit(tsk, code);

---
base-commit: bfc17c1658353f22843c7c13e27c2d31950f1887
change-id: 20250403-exit-bf815877a1cd

Best regards,
-- 
Breno Leitao <leitao@...ian.org>