linux-kernel - [PATCH 5/9] panic: use panic_try

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Message-ID: <20250820091702.512524-6-wangjinchao600@gmail.com>
Date: Wed, 20 Aug 2025 17:14:50 +0800
From: Jinchao Wang <wangjinchao600@...il.com>
To: pmladek@...e.com,
	akpm@...ux-foundation.org,
	Feng Tang <feng.tang@...ux.alibaba.com>,
	John Ogness <john.ogness@...utronix.de>,
	Jinchao Wang <wangjinchao600@...il.com>,
	Joel Granados <joel.granados@...nel.org>,
	Nam Cao <namcao@...utronix.de>,
	Sravan Kumar Gundu <sravankumarlpu@...il.com>
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 5/9] panic: use panic_try_start() in vpanic()

vpanic() had open-coded logic to claim
panic_cpu with atomic_try_cmpxchg. This is
already handled by panic_try_start().

Switch to panic_try_start() and use
panic_on_other_cpu() for the fallback path.

This removes duplicate code and makes panic
handling consistent across functions.

Signed-off-by: Jinchao Wang <wangjinchao600@...il.com>
---
 kernel/panic.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index cd86d37d124c..5266e195f5ac 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -415,7 +415,6 @@ void vpanic(const char *fmt, va_list args)
 	static char buf[1024];
 	long i, i_next = 0, len;
 	int state = 0;
-	int old_cpu, this_cpu;
 	bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
 
 	if (panic_on_warn) {
@@ -452,13 +451,10 @@ void vpanic(const char *fmt, va_list args)
 	 * `old_cpu == this_cpu' means we came from nmi_panic() which sets
 	 * panic_cpu to this CPU.  In this case, this is also the 1st CPU.
 	 */
-	old_cpu = PANIC_CPU_INVALID;
-	this_cpu = raw_smp_processor_id();
-
 	/* atomic_try_cmpxchg updates old_cpu on failure */
-	if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) {
+	if (panic_try_start()) {
 		/* go ahead */
-	} else if (old_cpu != this_cpu)
+	} else if (panic_on_other_cpu())
 		panic_smp_self_stop();
 
 	console_verbose();
-- 
2.43.0