On Sat, Aug 20, 2022 at 08:14:42PM +0200, Greg Kroah-Hartman wrote:
On Fri, Aug 19, 2022 at 09:35:01PM +0200, Uwe Kleine-König wrote:
Hello Greg,
On Tue, Aug 16, 2022 at 12:40:50PM +0200, Greg Kroah-Hartman wrote:
On Mon, Aug 15, 2022 at 11:49:11PM +0200, Uwe Kleine-König wrote:
On Mon, Aug 15, 2022 at 07:52:27PM +0200, Greg Kroah-Hartman wrote:
From: Uwe Kleine-König u.kleine-koenig@pengutronix.de
[ Upstream commit 7d4edccc9bbfe1dcdff641343f7b0c6763fbe774 ]
Taking a lock at the beginning of .remove() doesn't prevent new readers. With the existing approach it can happen, that a read occurs just when the lock was taken blocking the reader until the lock is released at the end of the remove callback which then accessed *data that is already freed then.
To actually fix this problem the hwmon core needs some adaption. Until this is implemented take the optimistic approach of assuming that all readers are gone after hwmon_device_unregister() and sysfs_remove_group() as most other drivers do. (And once the core implements that, taking the lock would deadlock.)
So drop the lock, move the reset to after device unregistration to keep the device in a workable state until it's deregistered. Also add a error message in case the reset fails and return 0 anyhow. (Returning an error code, doesn't stop the platform device unregistration and only results in a little helpful error message before the devm cleanup handlers are called.)
Signed-off-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Link: https://lore.kernel.org/r/20220725194344.150098-1-u.kleine-koenig@pengutroni... Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Sasha Levin sashal@kernel.org
Does this mean my concerns I expressed in the mail with Message-Id: 20220814155638.idxnihylofsxqlql@pengutronix.de were not taken into consideration?
I can't find that message-id on lore.kernel.org, do you have a link?
Oh, I missed your request earlier. No I don't have a link, the mail was sent to Sasha Levin, Jean Delvare, Guenter Roeck and stable-commits as I just replied to the "note to let you know that I've just added the patch titled [...] to the 5.19-stable tree".
Ok, I've dropped it now from all pending queues (5.10 and older), I can also revert it from the newer ones if you want me to.
Actually I don't care much. It touches a path that is not usually hit, because platform devices are not removed very often. So I expect even if the problem with this driver is a different one now, we won't get any regressions here.
Best regards Uwe