On Sun Mar 2 17:58:25 2025 +0300, Nikita Zhandarovich wrote:
> Syzbot reported [1] a warning prompted by a check in call_s_stream()
> that checks whether .s_stream() operation is warranted for unstarted
> or stopped subdevs.
> 
> Add a simple fix in vimc_streamer_pipeline_terminate() ensuring that
> entities skip a call to .s_stream() unless they have been previously
> properly started.
> 
> [1] Syzbot report:
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 5933 at drivers/media/v4l2-core/v4l2-subdev.c:460 
> call_s_stream+0x2df/0x350 drivers/media/v4l2-core/v4l2-subdev.c:460
> Modules linked in:
> CPU: 0 UID: 0 PID: 5933 Comm: syz-executor330 Not tainted 
> 6.13.0-rc2-syzkaller-00362-g2d8308bf5b67 #0
> ...
> Call Trace:
>  <TASK>
>  vimc_streamer_pipeline_terminate+0x218/0x320 
> drivers/media/test-drivers/vimc/vimc-streamer.c:62
>  vimc_streamer_pipeline_init 
> drivers/media/test-drivers/vimc/vimc-streamer.c:101 [inline]
>  vimc_streamer_s_stream+0x650/0x9a0 
> drivers/media/test-drivers/vimc/vimc-streamer.c:203
>  vimc_capture_start_streaming+0xa1/0x130 
> drivers/media/test-drivers/vimc/vimc-capture.c:256
>  vb2_start_streaming+0x15f/0x5a0 
> drivers/media/common/videobuf2/videobuf2-core.c:1789
>  vb2_core_streamon+0x2a7/0x450 
> drivers/media/common/videobuf2/videobuf2-core.c:2348
>  vb2_streamon drivers/media/common/videobuf2/videobuf2-v4l2.c:875 [inline]
>  vb2_ioctl_streamon+0xf4/0x170 
> drivers/media/common/videobuf2/videobuf2-v4l2.c:1118
>  __video_do_ioctl+0xaf0/0xf00 drivers/media/v4l2-core/v4l2-ioctl.c:3122
>  video_usercopy+0x4d2/0x1620 drivers/media/v4l2-core/v4l2-ioctl.c:3463
>  v4l2_ioctl+0x1ba/0x250 drivers/media/v4l2-core/v4l2-dev.c:366
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:906 [inline]
>  __se_sys_ioctl fs/ioctl.c:892 [inline]
>  __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f2b85c01b19
> ...
> 
> Reported-by: syzbot+5bcd7c809d365e14c...@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=5bcd7c809d365e14c4df
> Fixes: adc589d2a208 ("media: vimc: Add vimc-streamer for stream control")
> Cc: sta...@vger.kernel.org
> Signed-off-by: Nikita Zhandarovich <n.zhandarov...@fintech.ru>
> Signed-off-by: Hans Verkuil <hverk...@xs4all.nl>

Patch committed.

Thanks,
Hans Verkuil

 drivers/media/test-drivers/vimc/vimc-streamer.c | 6 ++++++
 1 file changed, 6 insertions(+)

---

diff --git a/drivers/media/test-drivers/vimc/vimc-streamer.c 
b/drivers/media/test-drivers/vimc/vimc-streamer.c
index 807551a5143b..15d863f97cbf 100644
--- a/drivers/media/test-drivers/vimc/vimc-streamer.c
+++ b/drivers/media/test-drivers/vimc/vimc-streamer.c
@@ -59,6 +59,12 @@ static void vimc_streamer_pipeline_terminate(struct 
vimc_stream *stream)
                        continue;
 
                sd = media_entity_to_v4l2_subdev(ved->ent);
+               /*
+                * Do not call .s_stream() to stop an already
+                * stopped/unstarted subdev.
+                */
+               if (!v4l2_subdev_is_streaming(sd))
+                       continue;
                v4l2_subdev_call(sd, video, s_stream, 0);
        }
 }

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