From: Duoming Zhou Date: Thu, 28 Aug 2025 08:29:49 +0000 (+0800) Subject: ptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=8bf935cf789872350b04c1a6468b0a509f67afb2;p=linux-block.git ptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog The ptp_ocp_detach() only shuts down the watchdog timer if it is pending. However, if the timer handler is already running, the timer_delete_sync() is not called. This leads to race conditions where the devlink that contains the ptp_ocp is deallocated while the timer handler is still accessing it, resulting in use-after-free bugs. The following details one of the race scenarios. (thread 1) | (thread 2) ptp_ocp_remove() | ptp_ocp_detach() | ptp_ocp_watchdog() if (timer_pending(&bp->watchdog))| bp = timer_container_of() timer_delete_sync() | | devlink_free(devlink) //free | | bp-> //use Resolve this by unconditionally calling timer_delete_sync() to ensure the timer is reliably deactivated, preventing any access after free. Fixes: 773bda964921 ("ptp: ocp: Expose various resources on the timecard.") Signed-off-by: Duoming Zhou Reviewed-by: Vadim Fedorenko Link: https://patch.msgid.link/20250828082949.28189-1-duoming@zju.edu.cn Signed-off-by: Jakub Kicinski --- diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c index d39073dc4072..4e1286ce05c9 100644 --- a/drivers/ptp/ptp_ocp.c +++ b/drivers/ptp/ptp_ocp.c @@ -4557,8 +4557,7 @@ ptp_ocp_detach(struct ptp_ocp *bp) ptp_ocp_debugfs_remove_device(bp); ptp_ocp_detach_sysfs(bp); ptp_ocp_attr_group_del(bp); - if (timer_pending(&bp->watchdog)) - timer_delete_sync(&bp->watchdog); + timer_delete_sync(&bp->watchdog); if (bp->ts0) ptp_ocp_unregister_ext(bp->ts0); if (bp->ts1)