From: Zheng Wang zyytlz.wz@163.com
stable inclusion from stable-v6.6.2 commit 847599fffa528b2cdec4e21b6bf7586dad982132 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8IW7G
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ 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@163.com Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/media/pci/bt8xx/bttv-driver.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/media/pci/bt8xx/bttv-driver.c b/drivers/media/pci/bt8xx/bttv-driver.c index aa708a0e5eac..09a193bb87df 100644 --- a/drivers/media/pci/bt8xx/bttv-driver.c +++ b/drivers/media/pci/bt8xx/bttv-driver.c @@ -3474,6 +3474,7 @@ 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));