staging: rtl8723bs: fix potential race in expire_timeout_chk

The expire_timeout_chk function currently do lock and unlock inside the
loop before calling rtw_free_stainfo().

This can be risky as the list might be changed
when the lock is briefly released.

To fix this, move expired sta_info entries into a local free_list while
holding the lock, and then perform the actual freeing after the lock is
released.

Signed-off-by: Minu Jin <s9430939@naver.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://patch.msgid.link/20260131171153.3729458-1-s9430939@naver.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/rtl8723bs/core/rtw_ap.c b/drivers/staging/rtl8723bs/core/rtw_ap.c
index 477fe238add40c670b6064d9846c841368e22462..2900ff476fc18a81ff557623502f716c6e37080b 100644 (file)
--- a/drivers/staging/rtl8723bs/core/rtw_ap.c
+++ b/drivers/staging/rtl8723bs/core/rtw_ap.c
@@ -178,6 +178,8 @@ void expire_timeout_chk(struct adapter *padapter)
        struct sta_priv *pstapriv = &padapter->stapriv;
        u8 chk_alive_num = 0;
        char chk_alive_list[NUM_STA];
+       struct sta_info *psta_tmp;
+       LIST_HEAD(free_list);
        int i;
 
        spin_lock_bh(&pstapriv->auth_list_lock);
@@ -190,19 +192,19 @@ void expire_timeout_chk(struct adapter *padapter)
                if (psta->expire_to > 0) {
                        psta->expire_to--;
                        if (psta->expire_to == 0) {
-                               list_del_init(&psta->auth_list);
+                               list_move(&psta->auth_list, &free_list);
                                pstapriv->auth_list_cnt--;
-
-                               spin_unlock_bh(&pstapriv->auth_list_lock);
-
-                               rtw_free_stainfo(padapter, psta);
-
-                               spin_lock_bh(&pstapriv->auth_list_lock);
                        }
                }
        }
 
        spin_unlock_bh(&pstapriv->auth_list_lock);
+
+       list_for_each_entry_safe(psta, psta_tmp, &free_list, auth_list) {
+               list_del_init(&psta->auth_list);
+               rtw_free_stainfo(padapter, psta);
+       }
+
        psta = NULL;
 
        spin_lock_bh(&pstapriv->asoc_list_lock);