This is a note to let you know that I've just added the patch titled
mmc: tmio: avoid concurrent runs of mmc_request_done()
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mmc-tmio-avoid-concurrent-runs-of-mmc_request_done.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5f9561574bacb43fd5fc26704902bb993ba5b32f
Author: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Date: Tue Mar 5 11:42:56 2024 +0100
mmc: tmio: avoid concurrent runs of mmc_request_done()
[ Upstream commit e8d1b41e69d72c62865bebe8f441163ec00b3d44 ]
With the to-be-fixed commit, the reset_work handler cleared 'host->mrq'
outside of the spinlock protected critical section. That leaves a small
race window during execution of 'tmio_mmc_reset()' where the done_work
handler could grab a pointer to the now invalid 'host->mrq'. Both would
use it to call mmc_request_done() causing problems (see link below).
However, 'host->mrq' cannot simply be cleared earlier inside the
critical section. That would allow new mrqs to come in asynchronously
while the actual reset of the controller still needs to be done. So,
like 'tmio_mmc_set_ios()', an ERR_PTR is used to prevent new mrqs from
coming in but still avoiding concurrency between work handlers.
Reported-by: Dirk Behme <dirk.behme@xxxxxxxxxxxx>
Closes: https://lore.kernel.org/all/20240220061356.3001761-1-dirk.behme@xxxxxxxxxxxx/
Fixes: df3ef2d3c92c ("mmc: protect the tmio_mmc driver against a theoretical race")
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Tested-by: Dirk Behme <dirk.behme@xxxxxxxxxxxx>
Reviewed-by: Dirk Behme <dirk.behme@xxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 3.0+
Link: https://lore.kernel.org/r/20240305104423.3177-2-wsa+renesas@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index be7f18fd4836a..c253d176db691 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -259,6 +259,8 @@ static void tmio_mmc_reset_work(struct work_struct *work)
else
mrq->cmd->error = -ETIMEDOUT;
+ /* No new calls yet, but disallow concurrent tmio_mmc_done_work() */
+ host->mrq = ERR_PTR(-EBUSY);
host->cmd = NULL;
host->data = NULL;
