On 8/29/25 10:30, Qianqiang Liu wrote:
> On Mon, Aug 25, 2025 at 10:29:31AM +0800, Jinchao Wang wrote:
>> crash_kexec() had its own code to exclude parallel execution by setting
>> panic_cpu. This is already handled by panic_try_start(). Switch to
>> panic_try_start() to remove the duplication and keep the logic consistent.
>>
>> Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
>> ---
>> kernel/crash_core.c | 15 +++------------
>> 1 file changed, 3 insertions(+), 12 deletions(-)
>>
>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>> index a4ef79591eb2..bb38bbaf3a26 100644
>> --- a/kernel/crash_core.c
>> +++ b/kernel/crash_core.c
>> @@ -4,6 +4,7 @@
>> * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
>> */
>>
>> +#include "linux/panic.h"
>
> Can you change this line of code to #include <linux/panic.h>?
Yes, I will.
Thanks for the feedback.>
>> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>
>> #include <linux/buildid.h>
>> @@ -143,17 +144,7 @@ STACK_FRAME_NON_STANDARD(__crash_kexec);
>>
>> __bpf_kfunc void crash_kexec(struct pt_regs *regs)
>> {
>> - int old_cpu, this_cpu;
>> -
>> - /*
>> - * Only one CPU is allowed to execute the crash_kexec() code as with
>> - * panic(). Otherwise parallel calls of panic() and crash_kexec()
>> - * may stop each other. To exclude them, we use panic_cpu here too.
>> - */
>> - old_cpu = PANIC_CPU_INVALID;
>> - this_cpu = raw_smp_processor_id();
>> -
>> - if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) {
>> + if (panic_try_start()) {
>> /* This is the 1st CPU which comes here, so go ahead. */
>> __crash_kexec(regs);
>>
>> @@ -161,7 +152,7 @@ __bpf_kfunc void crash_kexec(struct pt_regs *regs)
>> * Reset panic_cpu to allow another panic()/crash_kexec()
>> * call.
>> */
>> - atomic_set(&panic_cpu, PANIC_CPU_INVALID);
>> + panic_reset();
>> }
>> }
>>
>> --
>> 2.43.0
>
--
Best regards,
Jinchao