Messages in this thread | | | Date | Tue, 4 Oct 2022 14:32:45 +0200 | Subject | Re: [PATCH v1 1/3] coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel") | From | David Hildenbrand <> |
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On 26.09.22 09:44, Kalle Valo wrote: > 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."
Hi Kalle,
sorry for the late reply. Jonathan already queued v2 and sent it upstream.
I think that's it is already covered by the statement and that the additional example isn't required -- most of us learned the hard way that "excessive logging turns into its own problem" includes all weird kinds of kernel crashes. A panic/reboot due to a watchdog not firing is one such possible outcome.
Thanks!
-- Thanks,
David / dhildenb
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