thunderbolt: Do not double dequeue a configuration request

Some of our devices crash in tb_cfg_request_dequeue():

 general protection fault, probably for non-canonical address 0xdead000000000122

 CPU: 6 PID: 91007 Comm: kworker/6:2 Tainted: G U W 6.6.65
 RIP: 0010:tb_cfg_request_dequeue+0x2d/0xa0
 Call Trace:
 <TASK>
 ? tb_cfg_request_dequeue+0x2d/0xa0
 tb_cfg_request_work+0x33/0x80
 worker_thread+0x386/0x8f0
 kthread+0xed/0x110
 ret_from_fork+0x38/0x50
 ret_from_fork_asm+0x1b/0x30

The circumstances are unclear, however, the theory is that
tb_cfg_request_work() can be scheduled twice for a request:
first time via frame.callback from ring_work() and second
time from tb_cfg_request().  Both times kworkers will execute
tb_cfg_request_dequeue(), which results in double list_del()
from the ctl->request_queue (the list poison deference hints
at it: 0xdead000000000122).

Do not dequeue requests that don't have TB_CFG_REQUEST_ACTIVE
bit set.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/thunderbolt/ctl.c b/drivers/thunderbolt/ctl.c
index cd15e84c47f475994e3b5d02a33d9a2c0ecd3431..1db2e951b53facf79bed849206e2d8997eb553fd 100644 (file)
--- a/drivers/thunderbolt/ctl.c
+++ b/drivers/thunderbolt/ctl.c
@@ -151,6 +151,11 @@ static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
        struct tb_ctl *ctl = req->ctl;
 
        mutex_lock(&ctl->request_queue_lock);
+       if (!test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags)) {
+               mutex_unlock(&ctl->request_queue_lock);
+               return;
+       }
+
        list_del(&req->list);
        clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
        if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))