wifi: mac80211: shut down RX BA session timer on teardown

Tearing down an RX BA session can leave the session timer queued on a
freed tid_rx. Later timer-wheel processing and the timer callback itself
then run against freed memory.

An RX BAR handler can dereference tid_rx under RCU before teardown
unpublishes it and stay in its read-side critical section while teardown
deletes the session timer. The stale handler can then rearm the timer
after timer_delete_sync() returns and before the RCU callback frees
tid_rx.

Use timer_shutdown_sync() so rearm attempts become ineffective once
teardown starts. Keep reorder_timer unchanged: teardown marks the session
removed under reorder_lock and its release path checks that state before
rearming. session_timer has no equivalent guard because
ieee80211_rx_h_ctrl() rearms it before taking reorder_lock.

Fixes: a87f736d942c ("mac80211: use RCU for RX aggregation")
Cc: stable@kernel.org # 5.15+
Assisted-by: LLM sparse kasan
Signed-off-by: Zhao Li <enderaoelyther@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

0 files changed, 0 insertions, 0 deletions