From: Petr Mladek <pmladek@suse.com>
To: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
kernel@gpiccoli.net, senozhatsky@chromium.org,
rostedt@goodmis.org, john.ogness@linutronix.de,
feng.tang@intel.com, kexec@lists.infradead.org,
dyoung@redhat.com, keescook@chromium.org, anton@enomsg.org,
ccross@android.com, tony.luck@intel.com
Subject: Re: [PATCH V2] panic: Move panic_print before kmsg dumpers
Date: Thu, 13 Jan 2022 12:50:06 +0100 [thread overview]
Message-ID: <Yd/0K1x7ILw3Qa46@alley> (raw)
In-Reply-To: <20220106212835.119409-1-gpiccoli@igalia.com>
On Thu 2022-01-06 18:28:35, Guilherme G. Piccoli wrote:
> The panic_print setting allows users to collect more information in a
> panic event, like memory stats, tasks, CPUs backtraces, etc.
> This is a pretty interesting debug mechanism, but currently the print
> event happens *after* kmsg_dump(), meaning that pstore, for example,
> cannot collect a dmesg with the panic_print information.
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -249,7 +252,7 @@ void panic(const char *fmt, ...)
> * show some extra information on kernel log if it was set...
> */
> if (kexec_crash_loaded())
> - panic_print_sys_info();
> + panic_print_sys_info(false);
panic_print_sys_info(false) will be called twice when both
kexec_crash_loaded() and _crash_kexec_post_notifiers are true.
Do we really need to call panic_print_sys_info() here? All information
provided by panic_print_sys_info(false) can be found also in
the crash dump.
> /*
> * If we have crashed and we have a crash kernel loaded let it handle
> @@ -283,6 +286,8 @@ void panic(const char *fmt, ...)
> */
> atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
>
> + panic_print_sys_info(false);
This is where the info might be printed 2nd time.
> +
> kmsg_dump(KMSG_DUMP_PANIC);
>
> /*
Otherwise, the change makes sense to me.
Best Regards,
Petr
WARNING: multiple messages have this Message-ID (diff)
From: Petr Mladek <pmladek@suse.com>
To: kexec@lists.infradead.org
Subject: [PATCH V2] panic: Move panic_print before kmsg dumpers
Date: Thu, 13 Jan 2022 12:50:06 +0100 [thread overview]
Message-ID: <Yd/0K1x7ILw3Qa46@alley> (raw)
In-Reply-To: <20220106212835.119409-1-gpiccoli@igalia.com>
On Thu 2022-01-06 18:28:35, Guilherme G. Piccoli wrote:
> The panic_print setting allows users to collect more information in a
> panic event, like memory stats, tasks, CPUs backtraces, etc.
> This is a pretty interesting debug mechanism, but currently the print
> event happens *after* kmsg_dump(), meaning that pstore, for example,
> cannot collect a dmesg with the panic_print information.
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -249,7 +252,7 @@ void panic(const char *fmt, ...)
> * show some extra information on kernel log if it was set...
> */
> if (kexec_crash_loaded())
> - panic_print_sys_info();
> + panic_print_sys_info(false);
panic_print_sys_info(false) will be called twice when both
kexec_crash_loaded() and _crash_kexec_post_notifiers are true.
Do we really need to call panic_print_sys_info() here? All information
provided by panic_print_sys_info(false) can be found also in
the crash dump.
> /*
> * If we have crashed and we have a crash kernel loaded let it handle
> @@ -283,6 +286,8 @@ void panic(const char *fmt, ...)
> */
> atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
>
> + panic_print_sys_info(false);
This is where the info might be printed 2nd time.
> +
> kmsg_dump(KMSG_DUMP_PANIC);
>
> /*
Otherwise, the change makes sense to me.
Best Regards,
Petr
next prev parent reply other threads:[~2022-01-13 11:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-06 21:28 [PATCH V2] panic: Move panic_print before kmsg dumpers Guilherme G. Piccoli
2022-01-06 21:28 ` Guilherme G. Piccoli
2022-01-13 11:50 ` Petr Mladek [this message]
2022-01-13 11:50 ` Petr Mladek
2022-01-13 12:34 ` Guilherme G. Piccoli
2022-01-13 12:34 ` Guilherme G. Piccoli
2022-01-13 14:22 ` Petr Mladek
2022-01-13 14:22 ` Petr Mladek
2022-01-13 15:15 ` Guilherme G. Piccoli
2022-01-13 15:15 ` Guilherme G. Piccoli
2022-01-14 12:26 ` Petr Mladek
2022-01-14 12:26 ` Petr Mladek
2022-01-14 12:32 ` Guilherme G. Piccoli
2022-01-14 12:32 ` Guilherme G. Piccoli
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