[PATCH] wifi: ath6kl: fix use-after-free in aggr_reset_state()

[Daniel Hodges <git@danielhodges.dev>]

The aggr_reset_state() function uses timer_delete() (non-synchronous)
for the aggregation timer before proceeding to delete TID state and
before the structure is freed by callers like aggr_module_destroy().

If the timer callback (aggr_timeout) is executing when aggr_reset_state()
is called, the callback will continue to access aggr_conn fields like
rx_tid[] and stat[] which may be freed immediately after by
kfree(aggr_info->aggr_conn) in aggr_module_destroy().

Additionally, the timer callback can re-arm itself via mod_timer() while
aggr_reset_state() is running, creating a more complex race condition.

Use timer_delete_sync() instead to ensure any running timer callback
has completed before returning.

Fixes: bdcd81707973 ("Add ath6kl cleaned up driver")
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Hodges <git@danielhodges.dev>
---
 drivers/net/wireless/ath/ath6kl/txrx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath6kl/txrx.c b/drivers/net/wireless/ath/ath6kl/txrx.c
index c3b06b515c4f..25ff5dec221c 100644
--- a/drivers/net/wireless/ath/ath6kl/txrx.c
+++ b/drivers/net/wireless/ath/ath6kl/txrx.c
@@ -1828,7 +1828,7 @@ void aggr_reset_state(struct aggr_info_conn *aggr_conn)
 		return;
 
 	if (aggr_conn->timer_scheduled) {
-		timer_delete(&aggr_conn->timer);
+		timer_delete_sync(&aggr_conn->timer);
 		aggr_conn->timer_scheduled = false;
 	}
 
-- 
2.52.0