This is a note to let you know that I've just added the patch titled mac80211: fix a memory leak where sta_info is not freed to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mac80211-fix-a-memory-leak-where-sta_info-is-not-freed.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 8f9dcc29566626f683843ccac6113a12208315ca Mon Sep 17 00:00:00 2001 From: Ahmed Zaki <anzaki@xxxxxxxxx> Date: Sat, 2 Oct 2021 08:53:29 -0600 Subject: mac80211: fix a memory leak where sta_info is not freed From: Ahmed Zaki <anzaki@xxxxxxxxx> commit 8f9dcc29566626f683843ccac6113a12208315ca upstream. The following is from a system that went OOM due to a memory leak: wlan0: Allocated STA 74:83:c2:64:0b:87 wlan0: Allocated STA 74:83:c2:64:0b:87 wlan0: IBSS finish 74:83:c2:64:0b:87 (---from ieee80211_ibss_add_sta) wlan0: Adding new IBSS station 74:83:c2:64:0b:87 wlan0: moving STA 74:83:c2:64:0b:87 to state 2 wlan0: moving STA 74:83:c2:64:0b:87 to state 3 wlan0: Inserted STA 74:83:c2:64:0b:87 wlan0: IBSS finish 74:83:c2:64:0b:87 (---from ieee80211_ibss_work) wlan0: Adding new IBSS station 74:83:c2:64:0b:87 wlan0: moving STA 74:83:c2:64:0b:87 to state 2 wlan0: moving STA 74:83:c2:64:0b:87 to state 3 . . wlan0: expiring inactive not authorized STA 74:83:c2:64:0b:87 wlan0: moving STA 74:83:c2:64:0b:87 to state 2 wlan0: moving STA 74:83:c2:64:0b:87 to state 1 wlan0: Removed STA 74:83:c2:64:0b:87 wlan0: Destroyed STA 74:83:c2:64:0b:87 The ieee80211_ibss_finish_sta() is called twice on the same STA from 2 different locations. On the second attempt, the allocated STA is not destroyed creating a kernel memory leak. This is happening because sta_info_insert_finish() does not call sta_info_free() the second time when the STA already exists (returns -EEXIST). Note that the caller sta_info_insert_rcu() assumes STA is destroyed upon errors. Same fix is applied to -ENOMEM. Signed-off-by: Ahmed Zaki <anzaki@xxxxxxxxx> Link: https://lore.kernel.org/r/20211002145329.3125293-1-anzaki@xxxxxxxxx [change the error path label to use the existing code] Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: Viacheslav Sablin <sablin@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/mac80211/sta_info.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -641,13 +641,13 @@ static int sta_info_insert_finish(struct /* check if STA exists already */ if (sta_info_get_bss(sdata, sta->sta.addr)) { err = -EEXIST; - goto out_err; + goto out_cleanup; } sinfo = kzalloc(sizeof(struct station_info), GFP_KERNEL); if (!sinfo) { err = -ENOMEM; - goto out_err; + goto out_cleanup; } local->num_sta++; @@ -703,8 +703,8 @@ static int sta_info_insert_finish(struct out_drop_sta: local->num_sta--; synchronize_net(); + out_cleanup: cleanup_single_sta(sta); - out_err: mutex_unlock(&local->sta_mtx); kfree(sinfo); rcu_read_lock(); Patches currently in stable-queue which might be from anzaki@xxxxxxxxx are queue-5.15/mac80211-fix-a-memory-leak-where-sta_info-is-not-freed.patch