From: Steven Rostedt <rostedt@goodmis.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Marco Elver <elver@google.com>,
Anders Roxell <anders.roxell@linaro.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Jann Horn <jannh@google.com>,
Peter Zijlstra <peterz@infradead.org>,
boqun.feng@gmail.com, Lai Jiangshan <jiangshanlai@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
kasan-dev <kasan-dev@googlegroups.com>,
rcu@vger.kernel.org, Linux-MM <linux-mm@kvack.org>,
Alexander Potapenko <glider@google.com>,
linux-arm-kernel@lists.infradead.org, Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>,
tglx@linutronix.de, Dmitry Vyukov <dvyukov@google.com>
Subject: Re: linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...)
Date: Tue, 24 Nov 2020 15:32:45 -0500 [thread overview]
Message-ID: <20201124153245.5bda420d@oasis.local.home> (raw)
In-Reply-To: <20201124194308.GC8957@C02TD0UTHF1T.local>
On Tue, 24 Nov 2020 19:43:08 +0000
Mark Rutland <mark.rutland@arm.com> wrote:
> AFAICT, the issue is that arch_cpu_idle() can be dynamically traced with
> ftrace, and hence the tracing code can unexpectedly run without RCU
> watching. Since that's dynamic tracing, we can avoid it by marking
> arch_cpu_idle() and friends as noinstr.
Technically, ftrace doesn't care if RCU is watching or not, but the
callbacks might, and they need to do the rcu_is_watching() check if
they do.
Although, there's work to keep those areas from being traced, but to do
so, they really need to be minimal, where you don't ever want to trace
them.
-- Steve
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-11-24 20:34 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20201112175406.GF3249@paulmck-ThinkPad-P72>
[not found] ` <20201113175754.GA6273@paulmck-ThinkPad-P72>
[not found] ` <20201117105236.GA1964407@elver.google.com>
[not found] ` <20201117182915.GM1437@paulmck-ThinkPad-P72>
[not found] ` <20201118225621.GA1770130@elver.google.com>
[not found] ` <20201118233841.GS1437@paulmck-ThinkPad-P72>
[not found] ` <20201119125357.GA2084963@elver.google.com>
[not found] ` <20201119151409.GU1437@paulmck-ThinkPad-P72>
[not found] ` <20201119170259.GA2134472@elver.google.com>
[not found] ` <20201119184854.GY1437@paulmck-ThinkPad-P72>
2020-11-19 19:38 ` linux-next: stall warnings and deadlock on Arm64 (was: [PATCH] kfence: Avoid stalling...) Marco Elver
2020-11-19 21:35 ` Paul E. McKenney
2020-11-19 22:53 ` Will Deacon
2020-11-20 10:30 ` Mark Rutland
2020-11-20 14:03 ` Marco Elver
2020-11-23 19:32 ` Mark Rutland
2020-11-24 14:03 ` Marco Elver
2020-11-24 15:01 ` Paul E. McKenney
2020-11-24 19:43 ` Mark Rutland
2020-11-24 20:32 ` Steven Rostedt [this message]
2020-11-24 19:30 ` Mark Rutland
2020-11-25 9:45 ` Marco Elver
2020-11-25 10:28 ` Mark Rutland
2020-11-20 14:19 ` Marco Elver
2020-11-20 14:39 ` Paul E. McKenney
2020-11-20 15:22 ` Mark Rutland
2020-11-20 17:38 ` Paul E. McKenney
2020-11-20 18:02 ` Mark Rutland
2020-11-20 18:57 ` Paul E. McKenney
2020-11-20 15:26 ` Steven Rostedt
2020-11-20 18:17 ` Marco Elver
2020-11-20 18:57 ` Steven Rostedt
2020-11-20 19:16 ` Steven Rostedt
2020-11-20 19:22 ` Marco Elver
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