0daf8a201b
commit ad608fbcf166fec809e402d548761768f602702c upstream.
The event subscriptions are added to the subscribed event list while
holding a spinlock, but that lock is subsequently released while still
accessing the subscription object. This makes it possible to unsubscribe
the event --- and freeing the subscription object's memory --- while
the subscription object is simultaneously accessed.
Prevent this by adding a mutex to serialise the event subscription and
unsubscription. This also gives a guarantee to the callback ops that the
add op has returned before the del op is called.
This change also results in making the elems field less special:
subscriptions are only added to the event list once they are fully
initialised.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: stable@vger.kernel.org # for 4.14 and up
Fixes:
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|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| tuner-core.c | ||
| v4l2-common.c | ||
| v4l2-compat-ioctl32.c | ||
| v4l2-ctrls.c | ||
| v4l2-dev.c | ||
| v4l2-device.c | ||
| v4l2-event.c | ||
| v4l2-fh.c | ||
| v4l2-int-device.c | ||
| v4l2-ioctl.c | ||
| v4l2-mem2mem.c | ||
| v4l2-of.c | ||
| v4l2-subdev.c | ||
| videobuf-core.c | ||
| videobuf-dma-contig.c | ||
| videobuf-dma-sg.c | ||
| videobuf-dvb.c | ||
| videobuf-msm-mem.c | ||
| videobuf-vmalloc.c | ||
| videobuf2-core.c | ||
| videobuf2-dma-contig.c | ||
| videobuf2-dma-sg.c | ||
| videobuf2-memops.c | ||
| videobuf2-vmalloc.c | ||