From: Duoming Zhou Date: Wed, 8 Mar 2023 12:55:14 +0000 (+0000) Subject: media: netup_unidvb: fix use-after-free at del_timer() X-Git-Tag: baikal/aarch64/sdk5.10~91 X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=9d89d05b793c7bddbac99ad630672ac38888fc17;p=kernel.git 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@zju.edu.cn Fixes: 835320408f64 ("[media] netup_unidvb: NetUP Universal DVB-S/S2/T/T2/C PCI-E card driver") Signed-off-by: Duoming Zhou Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- diff --git a/drivers/media/pci/netup_unidvb/netup_unidvb_core.c b/drivers/media/pci/netup_unidvb/netup_unidvb_core.c index eb5621c9ebf85..129acf595410d 100644 --- a/drivers/media/pci/netup_unidvb/netup_unidvb_core.c +++ b/drivers/media/pci/netup_unidvb/netup_unidvb_core.c @@ -697,7 +697,7 @@ 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)