Il 20/10/23 06:07, Zheng Wang ha scritto:
In mtk_jpeg_probe, &jpeg->job_timeout_work is bound with
mtk_jpeg_job_timeout_work.
In mtk_jpeg_dec_device_run, if error happens in
mtk_jpeg_set_dec_dst, it will finally start the worker while
mark the job as finished by invoking v4l2_m2m_job_finish.
There are two methods to trigger the bug. If we remove the
module, it which will call mtk_jpeg_remove to make cleanup.
The possible sequence is as follows, which will cause a
use-after-free bug.
CPU0 CPU1
mtk_jpeg_dec_... |
start worker |
|mtk_jpeg_job_timeout_work
mtk_jpeg_remove |
v4l2_m2m_release |
kfree(m2m_dev); |
|
| v4l2_m2m_get_curr_priv
| m2m_dev->curr_ctx //use
If we close the file descriptor, which will call mtk_jpeg_release,
it will have a similar sequence.
Fix this bug by start timeout worker only if started jpegdec worker
successfully so the v4l2_m2m_job_finish will only be called on
either mtk_jpeg_job_timeout_work or mtk_jpeg_dec_device_run.
This patch also reverts commit c677d7ae8314
("media: mtk-jpeg: Fix use after free bug due to uncanceled work")
for this patch also fixed the use-after-free bug mentioned before.
Before mtk_jpeg_remove is invoked, mtk_jpeg_release must be invoked
to close opened files. And it will call v4l2_m2m_cancel_job to wait
for the timeout worker finished so the canceling in mtk_jpeg_remove
is unnecessary.
Fixes: b2f0d2724ba4 ("[media] vcodec: mediatek: Add Mediatek JPEG Decoder Driver")
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
