Re: [PATCH 2/3] s390: Implement arch_do_panic

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] arch_do_panic() is bypassed when panic_timeout != 0
- [Low] Unused declaration of s390_do_panic()
--

--- Patch [2]: [PATCH 2/3] s390: Implement arch_do_panic ---
commit 640e72aef0a165dacc87c9e5913aa8f9442aa6e9
Author: Mete Durlu <meted@linux.ibm.com>

s390: Implement arch_do_panic

This commit implements the arch_do_panic() hook for s390 to handle
architecture-specific panic actions instead of relying on the panic_notifier
chain. This change allows user-specified panic_timeout values to be evaluated
in common code before executing the s390 specific actions.

> diff --git a/arch/s390/include/asm/ipl.h b/arch/s390/include/asm/ipl.h
> index b0d00032479d6..38924c4a5d1d7 100644
> --- a/arch/s390/include/asm/ipl.h
> +++ b/arch/s390/include/asm/ipl.h
> @@ -166,5 +166,6 @@ enum diag308_rc {
>  extern int diag308(unsigned long subcode, void *addr);
>  extern void store_status(void (*fn)(void *), void *data);
>  extern void lgr_info_log(void);
> +void s390_do_panic(void);

[Severity: Low]
Is this declaration necessary? 

It looks like s390_do_panic() is declared here but never implemented or used,
as the actual implementation provided in arch/s390/kernel/ipl.c is named
arch_do_panic().

[ ... ]

> diff --git a/kernel/panic.c b/kernel/panic.c
> index 1eb0cdc159d94..de0bda946cabb 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -755,9 +755,6 @@ void vpanic(const char *fmt, va_list args)
>  		pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
>  			 "twice on console to return to the boot prom\n");
>  	}
> -#endif
> -#if defined(CONFIG_S390)
> -	disabled_wait();
>  #endif
>  	pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);

[Severity: High]
Does this change unintentionally bypass the s390 panic actions when
panic_timeout != 0?

Looking at vpanic() in kernel/panic.c, if a panic timeout is set, the system
will restart before reaching arch_do_panic():

    if (panic_timeout != 0) {
        ...
        emergency_restart();
    }
    pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);

    arch_do_panic();

Since emergency_restart() does not return, will the user-configured on_panic
actions be lost in this scenario?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260727-arch_do_panic-v1-0-ca1777547c38@linux.ibm.com?part=2