From db57a1aa54ff68669781976e4edb045e09e2b65b Mon Sep 17 00:00:00 2001 From: Jeongjun Park Date: Thu, 23 Apr 2026 02:38:46 +0900 Subject: [PATCH] wifi: rsi: fix kthread lifetime race between self-exit and external-stop RSI driver use both self-exit(kthread_complete_and_exit) and external-stop (kthread_stop) when killing a kthread. Generally, kthread_stop() is called first, and in this case, no particular issues occur. However, in rare instances where kthread_complete_and_exit() is called first and then kthread_stop() is called, a UAF occurs because the kthread object, which has already exited and been freed, is accessed again. Therefore, to prevent this with minimal modification, you must remove kthread_stop() and change the code to wait until the self-exit operation is completed. Cc: Reported-by: syzbot+5de83f57cd8531f55596@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69e5d03b.a00a0220.1bd0ca.0064.GAE@google.com/ Fixes: 4c62764d0fc2 ("rsi: improve kernel thread handling to fix kernel panic") Signed-off-by: Jeongjun Park Link: https://patch.msgid.link/20260422173846.37640-1-aha310510@gmail.com Signed-off-by: Johannes Berg --- drivers/net/wireless/rsi/rsi_common.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/rsi/rsi_common.h b/drivers/net/wireless/rsi/rsi_common.h index 591602beeec6..3cdf9ded876d 100644 --- a/drivers/net/wireless/rsi/rsi_common.h +++ b/drivers/net/wireless/rsi/rsi_common.h @@ -70,12 +70,11 @@ static inline int rsi_create_kthread(struct rsi_common *common, return 0; } -static inline int rsi_kill_thread(struct rsi_thread *handle) +static inline void rsi_kill_thread(struct rsi_thread *handle) { atomic_inc(&handle->thread_done); rsi_set_event(&handle->event); - - return kthread_stop(handle->task); + wait_for_completion(&handle->completion); } void rsi_mac80211_detach(struct rsi_hw *hw);