From: Peter Zijlstra <peterz@infradead.org>
To: Sven Schnelle <svens@linux.ibm.com>
Cc: hca@linux.ibm.com, linux-kernel@vger.kernel.org,
linux-s390@vger.kernel.org, rafael.j.wysocki@intel.com
Subject: Re: [PATCH] s390/idle: Fix suspicious RCU usage
Date: Wed, 7 Oct 2020 12:05:51 +0200 [thread overview]
Message-ID: <20201007100551.GC2628@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <yt9dimbm79qi.fsf@linux.ibm.com>
On Wed, Oct 07, 2020 at 09:53:25AM +0200, Sven Schnelle wrote:
> Hi Peter,
>
> peterz@infradead.org writes:
>
> > After commit eb1f00237aca ("lockdep,trace: Expose tracepoints") the
> > lock tracepoints are visible to lockdep and RCU-lockdep is finding a
> > bunch more RCU violations that were previously hidden.
> >
> > Switch the idle->seqcount over to using raw_write_*() to avoid the
> > lockdep annotation and thus the lock tracepoints.
> >
> > Reported-by: Guenter Roeck <linux@roeck-us.net>
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > [..]
>
> I'm still seeing the splat below on s390 when irq tracing is enabled:
Damn... :/
This one is tricky, trouble seems to be that arch_cpu_idle() is defined
to enable interrupts (no doubt because ot x86 :/), but we call it before
rcu_exit_idle().
What a mess... let me rummage around the various archs to see what makes
most sense here.
next prev parent reply other threads:[~2020-10-07 10:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-08 13:30 [PATCH] s390/idle: Fix suspicious RCU usage peterz
2020-09-08 13:41 ` Heiko Carstens
2020-10-07 7:53 ` Sven Schnelle
2020-10-07 10:05 ` Peter Zijlstra [this message]
2020-10-07 12:56 ` Peter Zijlstra
2020-10-08 8:58 ` Sven Schnelle
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