Messages in this thread | | | From | Valentin Schneider <> | Subject | Re: [PATCH v2] panic, kexec: Make __crash_kexec() NMI safe | Date | Thu, 23 Jun 2022 12:39:57 +0100 |
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On 23/06/22 11:31, Sebastian Andrzej Siewior wrote: > On 2022-06-20 12:15:20 [+0100], Valentin Schneider wrote: >> Attempting to get a crash dump out of a debug PREEMPT_RT kernel via an NMI >> panic() doesn't work. The cause of that lies in the PREEMPT_RT definition >> of mutex_trylock(): >> > … > >> Fixes: 6ce47fd961fa ("rtmutex: Warn if trylock is called from hard/softirq context") >> Signed-off-by: Valentin Schneider <vschneid@redhat.com> > > Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > >> --- >> v1 -> v2 >> ++++++++ >> >> o Changed from Peterson-like synchronization to simpler atomic_cmpxchg >> (Petr) >> o Slightly reworded changelog >> o Added Fixes: tag. Technically should be up to since kexec can happen >> in an NMI, but that isn't such a clear target > > RT-wise it would be needed for each release.
So git tells me the Fixes: commit dates from v4.2; from [1] and [2] I get that both current longterm stable and stable-rt trees go as far back as v4.9, so I'm guessing if that gets picked up for the stable trees then it should make its way into the stable -rt trees?
[1]: https://wiki.linuxfoundation.org/realtime/preempt_rt_versions [2]: https://www.kernel.org/category/releases.html
> There is also a mutex_unlock() in case an image is missing. This can go > via the scheduler if there is a waiter which does not look good with the > NMI in the picture. > > Sebastian
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