From: Valentin Schneider <vschneid@redhat.com> To: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-rt-users@vger.kernel.org, Eric Biederman <ebiederm@xmission.com>, Arnd Bergmann <arnd@arndb.de>, Petr Mladek <pmladek@suse.com>, Thomas Gleixner <tglx@linutronix.de>, Juri Lelli <jlelli@redhat.com>, "Luis Claudio R. Goncalves" <lgoncalv@redhat.com> Subject: Re: [PATCH v2] panic, kexec: Make __crash_kexec() NMI safe Date: Thu, 23 Jun 2022 12:39:57 +0100 [thread overview] Message-ID: <xhsmhy1xn622a.mognet@vschneid.remote.csb> (raw) In-Reply-To: <YrQzB7sPD8BNxSFq@linutronix.de> 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
WARNING: multiple messages have this Message-ID (diff)
From: Valentin Schneider <vschneid@redhat.com> To: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-rt-users@vger.kernel.org, Eric Biederman <ebiederm@xmission.com>, Arnd Bergmann <arnd@arndb.de>, Petr Mladek <pmladek@suse.com>, Thomas Gleixner <tglx@linutronix.de>, Juri Lelli <jlelli@redhat.com>, "Luis Claudio R. Goncalves" <lgoncalv@redhat.com> Subject: Re: [PATCH v2] panic, kexec: Make __crash_kexec() NMI safe Date: Thu, 23 Jun 2022 12:39:57 +0100 [thread overview] Message-ID: <xhsmhy1xn622a.mognet@vschneid.remote.csb> (raw) In-Reply-To: <YrQzB7sPD8BNxSFq@linutronix.de> 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 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2022-06-23 11:40 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-06-20 11:15 [PATCH v2] panic, kexec: Make __crash_kexec() NMI safe Valentin Schneider 2022-06-20 11:15 ` Valentin Schneider 2022-06-23 9:31 ` Sebastian Andrzej Siewior 2022-06-23 9:31 ` Sebastian Andrzej Siewior 2022-06-23 11:39 ` Valentin Schneider [this message] 2022-06-23 11:39 ` Valentin Schneider 2022-06-23 13:35 ` Sebastian Andrzej Siewior 2022-06-23 13:35 ` Sebastian Andrzej Siewior 2022-06-24 1:30 ` Baoquan He 2022-06-24 1:30 ` Baoquan He 2022-06-24 13:37 ` Valentin Schneider 2022-06-24 13:37 ` Valentin Schneider 2022-06-26 10:37 ` Baoquan He 2022-06-26 10:37 ` Baoquan He 2022-06-26 10:45 ` Baoquan He 2022-06-26 10:45 ` Baoquan He 2022-06-25 17:04 ` Eric W. Biederman 2022-06-25 17:04 ` Eric W. Biederman 2022-06-27 12:42 ` Valentin Schneider 2022-06-27 12:42 ` Valentin Schneider 2022-06-28 17:33 ` Valentin Schneider 2022-06-28 17:33 ` Valentin Schneider 2022-06-29 11:55 ` Petr Mladek 2022-06-29 11:55 ` Petr Mladek 2022-06-29 12:23 ` Valentin Schneider 2022-06-29 12:23 ` Valentin Schneider
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