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>
Cc: stable@xxxxxxxxxxxxxxx
---
.../media/platform/mediatek/jpeg/mtk_jpeg_core.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c b/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c
index 7194f88edc0f..c3456c700c07 100644
--- a/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c
+++ b/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c
@@ -1021,13 +1021,13 @@ static void mtk_jpeg_dec_device_run(void *priv)
if (ret < 0)
goto dec_end;
- schedule_delayed_work(&jpeg->job_timeout_work,
- msecs_to_jiffies(MTK_JPEG_HW_TIMEOUT_MSEC));
-
mtk_jpeg_set_dec_src(ctx, &src_buf->vb2_buf, &bs);
if (mtk_jpeg_set_dec_dst(ctx, &jpeg_src_buf->dec_param, &dst_buf->vb2_buf, &fb))
goto dec_end;
+ schedule_delayed_work(&jpeg->job_timeout_work,
+ msecs_to_jiffies(MTK_JPEG_HW_TIMEOUT_MSEC));
+
spin_lock_irqsave(&jpeg->hw_lock, flags);
mtk_jpeg_dec_reset(jpeg->reg_base);
mtk_jpeg_dec_set_config(jpeg->reg_base,
@@ -1403,7 +1403,6 @@ static void mtk_jpeg_remove(struct platform_device *pdev)
{
struct mtk_jpeg_dev *jpeg = platform_get_drvdata(pdev);
- cancel_delayed_work_sync(&jpeg->job_timeout_work);
pm_runtime_disable(&pdev->dev);
video_unregister_device(jpeg->vdev);
v4l2_m2m_release(jpeg->m2m_dev);
@@ -1750,9 +1749,6 @@ static void mtk_jpegdec_worker(struct work_struct *work)
v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx);
- schedule_delayed_work(&comp_jpeg[hw_id]->job_timeout_work,
- msecs_to_jiffies(MTK_JPEG_HW_TIMEOUT_MSEC));
-
mtk_jpeg_set_dec_src(ctx, &src_buf->vb2_buf, &bs);
if (mtk_jpeg_set_dec_dst(ctx,
&jpeg_src_buf->dec_param,
@@ -1762,6 +1758,9 @@ static void mtk_jpegdec_worker(struct work_struct *work)
goto setdst_end;
}
+ schedule_delayed_work(&comp_jpeg[hw_id]->job_timeout_work,
+ msecs_to_jiffies(MTK_JPEG_HW_TIMEOUT_MSEC));
+
spin_lock_irqsave(&comp_jpeg[hw_id]->hw_lock, flags);
ctx->total_frame_num++;
mtk_jpeg_dec_reset(comp_jpeg[hw_id]->reg_base);
--
2.25.1
