From: Leo Yan <leo.yan@arm.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mohamed Ayman <mohamedaymanworkspace@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@arm.com>,
James Clark <james.clark@linaro.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Clark Williams <clrkwllms@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
"moderated list:ARM/CORESIGHT FRAMEWORK AND DRIVERS"
<coresight@lists.linaro.org>,
"moderated list:ARM/CORESIGHT FRAMEWORK AND DRIVERS"
<linux-arm-kernel@lists.infradead.org>,
open list <linux-kernel@vger.kernel.org>,
"open list:Real-time Linux (PREEMPT_RT):Keyword:PREEMPT_RT"
<linux-rt-devel@lists.linux.dev>
Subject: Re: [PATCH v3] coresight: Fix scheduling while atomic in coresight_cpu_pm_notify()
Date: Fri, 17 Jul 2026 11:49:00 +0100 [thread overview]
Message-ID: <20260717104900.GA3998092@e132581.arm.com> (raw)
In-Reply-To: <20260717081453.pSDTUQQW@linutronix.de>
Hi Mohamed & Sebastian,
On Fri, Jul 17, 2026 at 10:14:53AM +0200, Sebastian Andrzej Siewior wrote:
[...]
> There is coresight_put_percpu_source_ref() with holds coresight_dev_lock
> during a put_cpu. I don't know why the lock is held, it is not obvious
> to me. But it will lead to a similar problem if the put actually invokes
> the release callback.
Sorry I am a bit late to join the discussion.
Essentially, this is about how to manage a module's lifetime correctly
so that the CPU PM notifier can safely access a device. There is an edge
case where the CPU PM notifier is accessing the device while, at the
same time, the module is being unloaded and the device's resources are
being released.
For now, I'd suggest please hold on this patch. Give me a bit time to
study this thread, I will share back more details.
Thanks,
Leo
prev parent reply other threads:[~2026-07-17 10:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-12 21:04 [PATCH] coresight: Fix scheduling while atomic in coresight_device_release() Mohamed Ayman
2026-07-13 3:07 ` Jie Gan
2026-07-13 23:00 ` [PATCH v2] coresight: Fix scheduling while atomic in coresight_put_percpu_source_ref() Mohamed Ayman
2026-07-14 10:42 ` Sebastian Andrzej Siewior
2026-07-14 19:42 ` MOHAMED AYMAN
2026-07-15 6:58 ` Sebastian Andrzej Siewior
2026-07-16 3:07 ` MOHAMED AYMAN
2026-07-16 12:32 ` Sebastian Andrzej Siewior
2026-07-16 21:41 ` [PATCH v3] coresight: Fix scheduling while atomic in coresight_cpu_pm_notify() Mohamed Ayman
2026-07-17 8:14 ` Sebastian Andrzej Siewior
2026-07-17 10:49 ` Leo Yan [this message]
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