The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x d9a02e016aaf5a57fb44e9a5e6da8ccd3b9e2e70 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '168000726237133@kroah.com' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

d9a02e016aaf ("dm crypt: avoid accessing uninitialized tasklet") d3703ef33129 ("dm crypt: use in_hardirq() instead of deprecated in_irq()") c87a95dc28b1 ("dm crypt: defer decryption to a tasklet if interrupts disabled") 8e14f610159d ("dm crypt: do not call bio_endio() from the dm-crypt tasklet")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d9a02e016aaf5a57fb44e9a5e6da8ccd3b9e2e70 Mon Sep 17 00:00:00 2001 From: Mike Snitzer snitzer@kernel.org Date: Wed, 8 Mar 2023 14:39:54 -0500 Subject: [PATCH] dm crypt: avoid accessing uninitialized tasklet

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: stable@vger.kernel.org Reported-by: Hou Tao houtao1@huawei.com Suggested-by: Ignat Korchagin ignat@cloudflare.com Reviewed-by: Ignat Korchagin ignat@cloudflare.com Signed-off-by: Mike Snitzer snitzer@kernel.org

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index faba1be572f9..2764b4ea18a3 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -72,7 +72,9 @@ 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;

@@ -1731,6 +1733,7 @@ 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); }

@@ -1777,14 +1780,13 @@ 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); }

/* @@ -2233,6 +2235,7 @@ static void kcryptd_queue_crypt(struct dm_crypt_io *io) * it is being executed with irqs disabled. */ if (in_hardirq() || irqs_disabled()) { + io->in_tasklet = true; tasklet_init(&io->tasklet, kcryptd_crypt_tasklet, (unsigned long)&io->work); tasklet_schedule(&io->tasklet); return;