From: Kalle Valo <kvalo@kernel.org>
To: David Hildenbrand <david@redhat.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>,
Baoquan He <bhe@redhat.com>,
linux-doc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Dave Young <dyoung@redhat.com>, Jonathan Corbet <corbet@lwn.net>,
Nicholas Piggin <npiggin@gmail.com>,
linux-kernel@vger.kernel.org,
Jani Nikula <jani.nikula@linux.intel.com>,
linux-mm@kvack.org, David Laight <David.Laight@ACULAB.COM>,
Dwaipayan Ray <dwaipayanray1@gmail.com>,
Andy Whitcroft <apw@canonical.com>, Joe Perches <joe@perches.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH v1 1/3] coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel")
Date: Mon, 26 Sep 2022 10:44:23 +0300 [thread overview]
Message-ID: <87leq64m20.fsf@kernel.org> (raw)
In-Reply-To: <d1ceedca-b28e-c47e-aa0d-aa1cb36d12b9@redhat.com> (David Hildenbrand's message of "Thu, 22 Sep 2022 16:12:05 +0200")
David Hildenbrand <david@redhat.com> writes:
>>> +Use WARN_ON_ONCE() rather than WARN() or WARN_ON()
>>> +**************************************************
>>> +
>>> +WARN_ON_ONCE() is generally preferred over WARN() or WARN_ON(), because it
>>> +is common for a given warning condition, if it occurs at all, to occur
>>> +multiple times. This can fill up and wrap the kernel log, and can even slow
>>> +the system enough that the excessive logging turns into its own, additional
>>> +problem.
>>
>> FWIW I have had cases where WARN() messages caused a reboot, maybe
>> mention that here? In my case the logging was so excessive that the
>> watchdog wasn't updated and in the end the device was forcefully
>> rebooted.
>>
>
> That should be covered by the last part, no? What would be your suggestion?
I was just thinking that maybe make it more obvious that even WARN_ON()
can crash the system, something along these lines:
"..., additional problem like stalling the system so much that it causes
a reboot."
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
next prev parent reply other threads:[~2022-09-26 7:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-20 12:22 [PATCH v1 0/3] coding-style.rst: document BUG() and WARN() rules David Hildenbrand
2022-09-20 12:23 ` [PATCH v1 1/3] coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel") David Hildenbrand
2022-09-21 4:40 ` Kalle Valo
2022-09-22 14:12 ` David Hildenbrand
2022-09-26 7:44 ` Kalle Valo [this message]
2022-10-04 12:32 ` David Hildenbrand
2022-09-22 13:43 ` Akira Yokosawa
2022-09-22 14:41 ` David Hildenbrand
2022-09-23 2:26 ` John Hubbard
2022-09-23 2:37 ` John Hubbard
2022-09-23 10:55 ` David Hildenbrand
2022-09-20 12:23 ` [PATCH v1 2/3] powerpc/prom_init: drop PROM_BUG() David Hildenbrand
2022-09-21 13:02 ` Michael Ellerman
2022-09-21 13:03 ` David Hildenbrand
2022-09-20 12:23 ` [PATCH v1 3/3] checkpatch: warn on usage of VM_BUG_ON() and other BUG variants David Hildenbrand
2022-09-23 2:05 ` John Hubbard
2022-09-23 2:11 ` Joe Perches
2022-09-23 2:20 ` John Hubbard
2022-09-23 10:58 ` David Hildenbrand
2022-10-04 13:24 ` (subset) [PATCH v1 0/3] coding-style.rst: document BUG() and WARN() rules Michael Ellerman
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