From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suzuki K Poulose Date: Thu, 28 Apr 2022 09:11:10 +0100 Subject: [PATCH 09/30] coresight: cpu-debug: Replace mutex with mutex_trylock on panic notifier In-Reply-To: <20220427224924.592546-10-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-10-gpiccoli@igalia.com> Message-ID: <3cafe4fd-8a0b-2633-44a3-2995abd6c38c@arm.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org Hi Guilherme, On 27/04/2022 23:49, Guilherme G. Piccoli wrote: > The panic notifier infrastructure executes registered callbacks when > a panic event happens - such callbacks are executed in atomic context, > with interrupts and preemption disabled in the running CPU and all other > CPUs disabled. That said, mutexes in such context are not a good idea. > > This patch replaces a regular mutex with a mutex_trylock safer approach; > given the nature of the mutex used in the driver, it should be pretty > uncommon being unable to acquire such mutex in the panic path, hence > no functional change should be observed (and if it is, that would be > likely a deadlock with the regular mutex). > > Fixes: 2227b7c74634 ("coresight: add support for CPU debug module") > Cc: Leo Yan > Cc: Mathieu Poirier > Cc: Mike Leach > Cc: Suzuki K Poulose > Signed-off-by: Guilherme G. Piccoli How would you like to proceed with queuing this ? I am happy either way. In case you plan to push this as part of this series (I don't see any potential conflicts) : Reviewed-by: Suzuki K Poulose