Shuah Khan 90cd366bc6 [media] media: Protect enable_source and disable_source handler code paths ... Drivers might try to access and run enable_source and disable_source handlers when the driver that implements these handlers is clearing the handlers during its unregister. Fix the following race condition: process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (doesn't hold graph_mutex) mdev->enable_source = NULL; if (mdev && mdev->enable_source) mdev->disable_source = NULL; mdev->enable_source() (enable_source holds graph_mutex) As shown above enable_source check is done without holding the graph_mutex. If unbind happens to be in progress, au0828 could clear enable_source and disable_source handlers leading to null pointer de-reference. Fix it by protecting enable_source and disable_source set and clear and protecting enable_source and disable_source handler access and the call itself. process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (hold graph_mutex while clearing) mdev->enable_source = NULL; if (mdev) mdev->disable_source = NULL; (hold graph_mutex to check and call enable_source) if (mdev->enable_source) mdev->enable_source() If graph_mutex is held to just heck for handler being null and needs to be released before calling the handler, there will be another window for the handlers to be cleared. Hence, enable_source and disable_source handlers no longer hold the graph_mutex and expect callers to hold it to avoid forcing them release the graph_mutex before calling the handlers. Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>		2017-02-03 07:39:35 -02:00
..
au0828-cards.c	[media] media: Drop FSF's postal address from the source code files	2017-01-27 11:38:09 -02:00
au0828-cards.h	[media] media: Drop FSF's postal address from the source code files	2017-01-27 11:38:09 -02:00
au0828-core.c	[media] media: Protect enable_source and disable_source handler code paths	2017-02-03 07:39:35 -02:00
au0828-dvb.c	[media] media: Drop FSF's postal address from the source code files	2017-01-27 11:38:09 -02:00
au0828-i2c.c	[media] media: Drop FSF's postal address from the source code files	2017-01-27 11:38:09 -02:00
au0828-input.c	[media] rc-main: assign driver type during allocation	2017-01-30 13:59:57 -02:00
au0828-reg.h	[media] media: Drop FSF's postal address from the source code files	2017-01-27 11:38:09 -02:00
au0828-vbi.c	[media] vb2: replace void *alloc_ctxs by struct device *alloc_devs	2016-07-08 14:45:07 -03:00
au0828-video.c	[media] media: Drop FSF's postal address from the source code files	2017-01-27 11:38:09 -02:00
au0828.h	[media] media: Drop FSF's postal address from the source code files	2017-01-27 11:38:09 -02:00
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