Commit c95930ab authored by Min Li's avatar Min Li Committed by Luiz Augusto von Dentz

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: default avatarMin Li <lm0963hack@gmail.com>
Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
parent b62e7220
......@@ -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,
......
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