From c95930abd687fcd1aa040dc4fe90dff947916460 Mon Sep 17 00:00:00 2001 From: Min Li Date: Sat, 4 Mar 2023 22:23:30 +0800 Subject: [PATCH] Bluetooth: Fix race condition in hidp_session_thread There is a potential race condition in hidp_session_thread that may lead to use-after-free. For instance, the timer is active while hidp_del_timer is called in hidp_session_thread(). After hidp_session_put, then 'session' will be freed, causing kernel panic when hidp_idle_timeout is running. The solution is to use del_timer_sync instead of del_timer. Here is the call trace: ? hidp_session_probe+0x780/0x780 call_timer_fn+0x2d/0x1e0 __run_timers.part.0+0x569/0x940 hidp_session_probe+0x780/0x780 call_timer_fn+0x1e0/0x1e0 ktime_get+0x5c/0xf0 lapic_next_deadline+0x2c/0x40 clockevents_program_event+0x205/0x320 run_timer_softirq+0xa9/0x1b0 __do_softirq+0x1b9/0x641 __irq_exit_rcu+0xdc/0x190 irq_exit_rcu+0xe/0x20 sysvec_apic_timer_interrupt+0xa1/0xc0 Cc: stable@vger.kernel.org Signed-off-by: Min Li Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/hidp/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c index bed1a7b9205c..707f229f896a 100644 --- a/net/bluetooth/hidp/core.c +++ b/net/bluetooth/hidp/core.c @@ -433,7 +433,7 @@ static void hidp_set_timer(struct hidp_session *session) static void hidp_del_timer(struct hidp_session *session) { if (session->idle_to > 0) - del_timer(&session->timer); + del_timer_sync(&session->timer); } static void hidp_process_report(struct hidp_session *session, int type,