| Message ID | 20230415080548.6230-1-duoming@zju.edu.cn |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [RESEND] media: netup_unidvb: fix use-after-free bug caused by del_timer() | expand |
diff --git a/drivers/media/pci/netup_unidvb/netup_unidvb_core.c b/drivers/media/pci/netup_unidvb/netup_unidvb_core.c index 8287851b5ff..aaa1d2dedeb 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)
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); | kfree(ndev); //FREE | | ndev->pci_dev->dev //USE Fix by changing del_timer() to del_timer_sync(). Fixes: 52b1eaf4c59a ("[media] netup_unidvb: NetUP Universal DVB-S/S2/T/T2/C PCI-E card driver") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- drivers/media/pci/netup_unidvb/netup_unidvb_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)