From 6f35f1059ccaa97583ac9ed21ce6e71e4ed4f2ad Mon Sep 17 00:00:00 2001 From: Zheng Wang Date: Thu, 13 Apr 2023 11:49:42 +0800 Subject: [PATCH] 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 Signed-off-by: Hans Verkuil Signed-off-by: Sasha Levin --- 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 dc651af04..b6f475ff4 100755 --- a/drivers/media/pci/bt8xx/bttv-driver.c +++ b/drivers/media/pci/bt8xx/bttv-driver.c @@ -4258,6 +4258,7 @@ 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));