From: Bart Van Assche <firstname.lastname@example.org> To: Alexander Duyck <email@example.com>, firstname.lastname@example.org, email@example.com Cc: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com Subject: Re: [driver-core PATCH v4 4/6] driver core: Probe devices asynchronously instead of the driver Date: Thu, 18 Oct 2018 13:13:56 -0700 [thread overview] Message-ID: <firstname.lastname@example.org> (raw) In-Reply-To: <email@example.com> On Thu, 2018-10-18 at 12:38 -0700, Alexander Duyck wrote: > Basically if somebody loads a driver the dev->driver becomes set. If a > driver is removed it will clear dev->driver and set driver_data to > 0/NULL. That is what I am using as a mutex to track it in conjunction > with the device mutex. Basically if somebody attempts to attach a driver > before we get there we just exit and don't attempt to load this driver. I don't think that the above matches your code. __device_attach() does not set the dev->driver pointer before scheduling an asynchronous probe. Only dev->driver_data gets set before the asynchonous probe is scheduled. Since driver_detach() only iterates over devices that are in the per-driver klist it will skip all devices for which an asynchronous probe has been scheduled but __device_attach_async_helper() has not yet been called. My conclusion remains that this patch does not prevent a driver pointer to become invalid concurrently with __device_attach_async_helper() dereferencing the same driver pointer. Bart.
next prev parent reply other threads:[~2018-10-18 20:14 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-10-15 15:09 [driver-core PATCH v4 0/6] Add NUMA aware async_schedule calls Alexander Duyck 2018-10-15 15:09 ` [driver-core PATCH v4 1/6] workqueue: Provide queue_work_node to queue work near a given NUMA node Alexander Duyck 2018-10-15 15:09 ` [driver-core PATCH v4 2/6] async: Add support for queueing on specific " Alexander Duyck 2018-10-15 15:09 ` [driver-core PATCH v4 3/6] device core: Consolidate locking and unlocking of parent and device Alexander Duyck 2018-10-18 7:46 ` Rafael J. Wysocki 2018-10-18 17:53 ` Bart Van Assche 2018-10-15 15:09 ` [driver-core PATCH v4 4/6] driver core: Probe devices asynchronously instead of the driver Alexander Duyck 2018-10-18 18:11 ` Bart Van Assche 2018-10-18 19:38 ` Alexander Duyck 2018-10-18 20:13 ` Bart Van Assche [this message] 2018-10-19 2:20 ` Alexander Duyck 2018-10-19 2:31 ` Bart Van Assche 2018-10-19 22:35 ` Alexander Duyck 2018-10-15 15:09 ` [driver-core PATCH v4 5/6] driver core: Attach devices on CPU local to device node Alexander Duyck 2018-10-15 15:09 ` [driver-core PATCH v4 6/6] PM core: Use new async_schedule_dev command Alexander Duyck
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