This is a note to let you know that I've just added the patch titled
dm crypt: avoid accessing uninitialized tasklet
to the 5.10-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:
dm-crypt-avoid-accessing-uninitialized-tasklet.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.
commit a95530ebdb4ef34ea248ae061d1fd676a6d4cc8e
Author: Mike Snitzer <snit...@kernel.org>
Date: Wed Mar 8 14:39:54 2023 -0500
dm crypt: avoid accessing uninitialized tasklet
[ Upstream commit d9a02e016aaf5a57fb44e9a5e6da8ccd3b9e2e70 ]
When neither "no_read_workqueue" nor "no_write_workqueue" are enabled,
tasklet_trylock() in crypt_dec_pending() may still return false due to
an uninitialized state, and dm-crypt will unnecessarily do io completion
in io_queue workqueue instead of current context.
Fix this by adding an 'in_tasklet' flag to dm_crypt_io struct and
initialize it to false in crypt_io_init(). Set this flag to true in
kcryptd_queue_crypt() before calling tasklet_schedule(). If set
crypt_dec_pending() will punt io completion to a workqueue.
This also nicely avoids the tasklet_trylock/unlock hack when tasklets
aren't in use.
Fixes: 8e14f610159d ("dm crypt: do not call bio_endio() from the dm-crypt
tasklet")
Cc: sta...@vger.kernel.org
Reported-by: Hou Tao <hout...@huawei.com>
Suggested-by: Ignat Korchagin <ig...@cloudflare.com>
Reviewed-by: Ignat Korchagin <ig...@cloudflare.com>
Signed-off-by: Mike Snitzer <snit...@kernel.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 17ddca293965c..5d772f322a245 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -67,7 +67,9 @@ struct dm_crypt_io {
struct crypt_config *cc;
struct bio *base_bio;
u8 *integrity_metadata;
- bool integrity_metadata_from_pool;
+ bool integrity_metadata_from_pool:1;
+ bool in_tasklet:1;
+
struct work_struct work;
struct tasklet_struct tasklet;
@@ -1722,6 +1724,7 @@ static void crypt_io_init(struct dm_crypt_io *io, struct
crypt_config *cc,
io->ctx.r.req = NULL;
io->integrity_metadata = NULL;
io->integrity_metadata_from_pool = false;
+ io->in_tasklet = false;
atomic_set(&io->io_pending, 0);
}
@@ -1767,14 +1770,13 @@ static void crypt_dec_pending(struct dm_crypt_io *io)
* our tasklet. In this case we need to delay bio_endio()
* execution to after the tasklet is done and dequeued.
*/
- if (tasklet_trylock(&io->tasklet)) {
- tasklet_unlock(&io->tasklet);
- bio_endio(base_bio);
+ if (io->in_tasklet) {
+ INIT_WORK(&io->work, kcryptd_io_bio_endio);
+ queue_work(cc->io_queue, &io->work);
return;
}
- INIT_WORK(&io->work, kcryptd_io_bio_endio);
- queue_work(cc->io_queue, &io->work);
+ bio_endio(base_bio);
}
/*
@@ -2228,6 +2230,7 @@ static void kcryptd_queue_crypt(struct dm_crypt_io *io)
* it is being executed with irqs disabled.
*/
if (in_irq() || irqs_disabled()) {
+ io->in_tasklet = true;
tasklet_init(&io->tasklet, kcryptd_crypt_tasklet,
(unsigned long)&io->work);
tasklet_schedule(&io->tasklet);
return;
--
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