[PATCH 4.4 055/104] media: vivid: fix error handling of kthread_run

From: Greg Kroah-Hartman
Date: Thu Jan 24 2019 - 14:26:21 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>

commit 701f49bc028edb19ffccd101997dd84f0d71e279 upstream.

kthread_run returns an error pointer, but elsewhere in the code
dev->kthread_vid_cap/out is checked against NULL.

If kthread_run returns an error, then set the pointer to NULL.

I chose this method over changing all kthread_vid_cap/out tests
elsewhere since this is more robust.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Reported-by: syzbot+53d5b2df0d9744411e2e@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/media/platform/vivid/vivid-kthread-cap.c | 5 ++++-
drivers/media/platform/vivid/vivid-kthread-out.c | 5 ++++-
2 files changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/media/platform/vivid/vivid-kthread-cap.c
+++ b/drivers/media/platform/vivid/vivid-kthread-cap.c
@@ -863,8 +863,11 @@ int vivid_start_generating_vid_cap(struc
"%s-vid-cap", dev->v4l2_dev.name);

if (IS_ERR(dev->kthread_vid_cap)) {
+ int err = PTR_ERR(dev->kthread_vid_cap);
+
+ dev->kthread_vid_cap = NULL;
v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n");
- return PTR_ERR(dev->kthread_vid_cap);
+ return err;
}
*pstreaming = true;
vivid_grab_controls(dev, true);
--- a/drivers/media/platform/vivid/vivid-kthread-out.c
+++ b/drivers/media/platform/vivid/vivid-kthread-out.c
@@ -248,8 +248,11 @@ int vivid_start_generating_vid_out(struc
"%s-vid-out", dev->v4l2_dev.name);

if (IS_ERR(dev->kthread_vid_out)) {
+ int err = PTR_ERR(dev->kthread_vid_out);
+
+ dev->kthread_vid_out = NULL;
v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n");
- return PTR_ERR(dev->kthread_vid_out);
+ return err;
}
*pstreaming = true;
vivid_grab_controls(dev, true);