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| author | Tong Zhang <ztong0001@gmail.com> | 2021-04-29 00:12:26 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-14 17:06:24 +0200 |
| commit | 6dc17634c1163cc50063196101bde584d6c9540a (patch) | |
| tree | 0610a20ba3598a999004cec3983088b9c77b3f56 /drivers/media | |
| parent | 2375ab34f7f3b029b7afa85f659f00b911028322 (diff) | |
| download | linux-stable-6dc17634c1163cc50063196101bde584d6c9540a.tar.gz linux-stable-6dc17634c1163cc50063196101bde584d6c9540a.tar.bz2 linux-stable-6dc17634c1163cc50063196101bde584d6c9540a.zip | |
media: bt878: do not schedule tasklet when it is not setup
[ Upstream commit a3a54bf4bddaecda8b5767209cfc703f0be2841d ]
There is a problem with the tasklet in bt878. bt->tasklet is set by
dvb-bt8xx.ko, and bt878.ko can be loaded independently.
In this case if interrupt comes it may cause null-ptr-dereference.
To solve this issue, we check if the tasklet is actually set before
calling tasklet_schedule.
[ 1.750438] bt878(0): irq FDSR FBUS risc_pc=
[ 1.750728] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 1.752969] RIP: 0010:0x0
[ 1.757526] Call Trace:
[ 1.757659] <IRQ>
[ 1.757770] tasklet_action_common.isra.0+0x107/0x110
[ 1.758041] tasklet_action+0x22/0x30
[ 1.758237] __do_softirq+0xe0/0x29b
[ 1.758430] irq_exit_rcu+0xa4/0xb0
[ 1.758618] common_interrupt+0x8d/0xa0
[ 1.758824] </IRQ>
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/pci/bt8xx/bt878.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/media/pci/bt8xx/bt878.c b/drivers/media/pci/bt8xx/bt878.c index 78dd35c9b65d..7ca309121fb5 100644 --- a/drivers/media/pci/bt8xx/bt878.c +++ b/drivers/media/pci/bt8xx/bt878.c @@ -300,7 +300,8 @@ static irqreturn_t bt878_irq(int irq, void *dev_id) } if (astat & BT878_ARISCI) { bt->finished_block = (stat & BT878_ARISCS) >> 28; - tasklet_schedule(&bt->tasklet); + if (bt->tasklet.callback) + tasklet_schedule(&bt->tasklet); break; } count++; |