This is a note to let you know that I've just added the patch titled
media: bttv: fix use after free error due to btv->timeout 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-bttv-fix-use-after-free-error-due-to-btv-timeo.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 6057cea072ea899c2d42fece88c24610c69fc914
Author: Zheng Wang <zyytlz.wz@xxxxxxx>
Date: Thu Apr 13 11:49:42 2023 +0800
media: bttv: fix use after free error due to btv->timeout timer
[ Upstream commit bd5b50b329e850d467e7bcc07b2b6bde3752fbda ]
There may be some a race condition between timer function
bttv_irq_timeout and bttv_remove. The timer is setup in
probe and there is no timer_delete operation in remove
function. When it hit kfree btv, the function might still be
invoked, which will cause use after free bug.
This bug is found by static analysis, it may be false positive.
Fix it by adding del_timer_sync invoking to the remove function.
cpu0 cpu1
bttv_probe
->timer_setup
->bttv_set_dma
->mod_timer;
bttv_remove
->kfree(btv);
->bttv_irq_timeout
->USE btv
Fixes: 162e6376ac58 ("media: pci: Convert timers to use timer_setup()")
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/pci/bt8xx/bttv-driver.c b/drivers/media/pci/bt8xx/bttv-driver.c
index 2a9d25431d733..fce894574c411 100644
--- a/drivers/media/pci/bt8xx/bttv-driver.c
+++ b/drivers/media/pci/bt8xx/bttv-driver.c
@@ -4300,6 +4300,7 @@ static void bttv_remove(struct pci_dev *pci_dev)
/* free resources */
free_irq(btv->c.pci->irq,btv);
+ del_timer_sync(&btv->timeout);
iounmap(btv->bt848_mmio);
release_mem_region(pci_resource_start(btv->c.pci,0),
pci_resource_len(btv->c.pci,0));
