This is a note to let you know that I've just added the patch titled
media: netup_unidvb: fix use-after-free at del_timer()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-netup_unidvb-fix-use-after-free-at-del_timer.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4b6cb554231a73ceb9597804133b01163b1b596b
Author: Duoming Zhou <duoming@xxxxxxxxxx>
Date: Wed Mar 8 12:55:14 2023 +0000
media: netup_unidvb: fix use-after-free at del_timer()
[ Upstream commit 0f5bb36bf9b39a2a96e730bf4455095b50713f63 ]
When Universal DVB card is detaching, netup_unidvb_dma_fini()
uses del_timer() to stop dma->timeout timer. But when timer
handler netup_unidvb_dma_timeout() is running, del_timer()
could not stop it. As a result, the use-after-free bug could
happen. The process is shown below:
(cleanup routine) | (timer routine)
| mod_timer(&dev->tx_sim_timer, ..)
netup_unidvb_finidev() | (wait a time)
netup_unidvb_dma_fini() | netup_unidvb_dma_timeout()
del_timer(&dma->timeout); |
| ndev->pci_dev->dev //USE
Fix by changing del_timer() to del_timer_sync().
Link: https://lore.kernel.org/linux-media/20230308125514.4208-1-duoming@xxxxxxxxxx
Fixes: 52b1eaf4c59a ("[media] netup_unidvb: NetUP Universal DVB-S/S2/T/T2/C PCI-E card driver")
Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/pci/netup_unidvb/netup_unidvb_core.c b/drivers/media/pci/netup_unidvb/netup_unidvb_core.c
index de3fc62810e6c..0ead74c40a7b7 100644
--- a/drivers/media/pci/netup_unidvb/netup_unidvb_core.c
+++ b/drivers/media/pci/netup_unidvb/netup_unidvb_core.c
@@ -706,7 +706,7 @@ static void netup_unidvb_dma_fini(struct netup_unidvb_dev *ndev, int num)
netup_unidvb_dma_enable(dma, 0);
msleep(50);
cancel_work_sync(&dma->work);
- del_timer(&dma->timeout);
+ del_timer_sync(&dma->timeout);
}
static int netup_unidvb_dma_setup(struct netup_unidvb_dev *ndev)
