From: Anand Moon <linux.amoon@gmail•com>
To: Neil Armstrong <neil.armstrong@linaro•org>,
Mauro Carvalho Chehab <mchehab@kernel•org>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
Kevin Hilman <khilman@baylibre•com>,
Jerome Brunet <jbrunet@baylibre•com>,
Martin Blumenstingl <martin.blumenstingl@googlemail•com>,
Maxime Jourdan <mjourdan@baylibre•com>,
Hans Verkuil <hverkuil@kernel•org>,
linux-media@vger•kernel.org (open list:MESON VIDEO DECODER
DRIVER FOR AMLOGIC SOCS),
linux-amlogic@lists•infradead.org (open list:MESON VIDEO DECODER
DRIVER FOR AMLOGIC SOCS),
linux-staging@lists•linux.dev (open list:STAGING SUBSYSTEM),
linux-arm-kernel@lists•infradead.org (moderated list:ARM/Amlogic
Meson SoC support), linux-kernel@vger•kernel.org (open list)
Cc: Sashiko <sashiko-bot@kernel•org>,
Nicolas Dufresne <nicolas@ndufresne•ca>
Subject: [PATCH v5 6/6] media: meson: vdec: Cancel esparser work in error and stop paths
Date: Mon, 25 May 2026 15:21:54 +0530 [thread overview]
Message-ID: <20260525095216.12078-7-linux.amoon@gmail.com> (raw)
In-Reply-To: <20260525095216.12078-1-linux.amoon@gmail.com>
The esparser workqueue may remain pending when streaming is stopped or
the device is closed, leading to use-after-free if it runs after session
teardown. vdec_start_streaming(), vdec_stop_streaming(), and vdec_close()
did not cancel this work, leaving a race between session cleanup and
work execution.
Fix this by calling cancel_work_sync(&sess->esparser_queue_work) in all
cleanup paths. Unlocking and relocking sess->lock around the cancel
ensures the work handler cannot run concurrently with teardown. This
prevents dangling work items from accessing freed session memory and
eliminates a potential kernel crash.
Cc: Nicolas Dufresne <nicolas@ndufresne•ca>
Reported-by: Sashiko <sashiko-bot@kernel•org>
Closes: https://lore.kernel.org/all/20260520045905.6ACBA1F000E9@smtp.kernel.org/#t
Fixes: 3e7f51bd9607 ("media: meson: add v4l2 m2m video decoder driver")
Signed-off-by: Anand Moon <linux.amoon@gmail•com>
---
v5: Tried to fix the order of cancel_work_sync() which could lead to
a use-after-free. update the commit message.
---
drivers/staging/media/meson/vdec/vdec.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/staging/media/meson/vdec/vdec.c b/drivers/staging/media/meson/vdec/vdec.c
index 925537bd4d0b..296b387f3667 100644
--- a/drivers/staging/media/meson/vdec/vdec.c
+++ b/drivers/staging/media/meson/vdec/vdec.c
@@ -372,6 +372,10 @@ static int vdec_start_streaming(struct vb2_queue *q, unsigned int count)
dma_free_coherent(sess->core->dev, sess->vififo_size,
sess->vififo_vaddr, sess->vififo_paddr);
bufs_done:
+ mutex_unlock(&sess->lock);
+ cancel_work_sync(&sess->esparser_queue_work);
+ mutex_lock(&sess->lock);
+
if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE) {
sess->streamon_out = 0;
while ((buf = v4l2_m2m_src_buf_remove(sess->m2m_ctx)))
@@ -430,6 +434,9 @@ static void vdec_stop_streaming(struct vb2_queue *q)
kthread_stop(sess->recycle_thread);
vdec_poweroff(sess);
+ mutex_unlock(&sess->lock);
+ cancel_work_sync(&sess->esparser_queue_work);
+ mutex_lock(&sess->lock);
vdec_free_canvas(sess);
dma_free_coherent(sess->core->dev, sess->vififo_size,
sess->vififo_vaddr, sess->vififo_paddr);
@@ -948,6 +955,8 @@ static int vdec_close(struct file *file)
{
struct amvdec_session *sess = file_to_amvdec_session(file);
+ cancel_work_sync(&sess->esparser_queue_work);
+
v4l2_m2m_ctx_release(sess->m2m_ctx);
v4l2_m2m_release(sess->m2m_dev);
v4l2_fh_del(&sess->fh, file);
--
2.50.1
prev parent reply other threads:[~2026-05-25 9:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-25 9:51 [PATCH v5 0/6] media: meson: Fix memory leak in error path in vdec Anand Moon
2026-05-25 9:51 ` [PATCH v5 1/6] media: meson: vdec: Fix memory leak in error path of vdec_open Anand Moon
2026-05-25 9:51 ` [PATCH v5 2/6] media: meson: vdec: Protect session exclusivity check with lock Anand Moon
2026-05-25 9:51 ` [PATCH v5 3/6] media: meson: vdec: Set cur_sess before hardware vdec_poweron() Anand Moon
2026-05-25 9:51 ` [PATCH v5 4/6] media: meson: vdec: Handle kthread error and free codec private data Anand Moon
2026-05-25 9:51 ` [PATCH v5 5/6] media: meson: vdec: Isolate error path buffer flush to the active queue Anand Moon
2026-05-25 9:51 ` Anand Moon [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260525095216.12078-7-linux.amoon@gmail.com \
--to=linux.amoon@gmail$(echo .)com \
--cc=gregkh@linuxfoundation$(echo .)org \
--cc=hverkuil@kernel$(echo .)org \
--cc=jbrunet@baylibre$(echo .)com \
--cc=khilman@baylibre$(echo .)com \
--cc=linux-amlogic@lists$(echo .)infradead.org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-media@vger$(echo .)kernel.org \
--cc=linux-staging@lists$(echo .)linux.dev \
--cc=martin.blumenstingl@googlemail$(echo .)com \
--cc=mchehab@kernel$(echo .)org \
--cc=mjourdan@baylibre$(echo .)com \
--cc=neil.armstrong@linaro$(echo .)org \
--cc=nicolas@ndufresne$(echo .)ca \
--cc=sashiko-bot@kernel$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox