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charset=utf-8 Content-Disposition: inline In-Reply-To: <20241122154051.3914732-1-elver@google.com> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 8881440002 X-Stat-Signature: 74ppw43jg1m6xhsbzp5gjxtddgr361r6 X-Rspam-User: X-HE-Tag: 1732297062-478834 X-HE-Meta: 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 IxgOe/Bz x7/lI29lFYsv8uXww2OCpPIogwQE2vKyvySwnOfxDv3yY2nZuAX71gYU9vhDII1ovAlCmdKHOJhshJK6iV2sWvU9jscOUk9U2SMvS/rkN6rhtG4HRtg05k43ULgtmzgfNExYpmysushXLHe2+XZgis+coGvW8zSxgs1Pepd2G8mAlXAViJ6/RJrZhNMIVeCYIg5RI5aqhjxdNvp3o7L87e576CUk9giATY/FrIcYKygRWsBw5EpHxcCL+9nlz/AnMg/iuEKKKCz3nl73tOv5aglahoAvBszu0UenLceS7NkZ/Gc4= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024-11-22 16:39:47 [+0100], Marco Elver wrote: > Per documentation, stack_depot_save_flags() was meant to be usable from > NMI context if STACK_DEPOT_FLAG_CAN_ALLOC is unset. However, it still > would try to take the pool_lock in an attempt to save a stack trace in > the current pool (if space is available). > > This could result in deadlock if an NMI is handled while pool_lock is > already held. To avoid deadlock, only try to take the lock in NMI > context and give up if unsuccessful. > > The documentation is fixed to clearly convey this. > > Link: https://lkml.kernel.org/r/Z0CcyfbPqmxJ9uJH@elver.google.com > Fixes: 4434a56ec209 ("stackdepot: make fast paths lock-less again") > Reported-by: Sebastian Andrzej Siewior > Signed-off-by: Marco Elver Reviewed-by: Sebastian Andrzej Siewior Sebastian