From: Min Li <lm0963hack@gmail.com>

Date: Sat, 4 Mar 2023 22:23:30 +0800

Subject: [PATCH] Bluetooth: Fix race condition in hidp_session_thread

References: bsc#1012628

Patch-mainline: 6.2.12

Git-commit: c95930abd687fcd1aa040dc4fe90dff947916460

commit c95930abd687fcd1aa040dc4fe90dff947916460 upstream.

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 <lm0963hack@gmail.com>

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>

---

 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 cc20e706..82cc15ad 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,

-- 

2.35.3