This is a note to let you know that I've just added the patch titled mac80211: Fix ieee80211_amsdu_aggregate frag_tail bug to the 5.14-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-ieee80211_amsdu_aggregate-frag_tail-bug.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 1102e73304236bc22044a333ca539e08a4b9bafd Author: Chih-Kang Chang <gary.chang@xxxxxxxxxxx> Date: Mon Aug 30 15:32:40 2021 +0800 mac80211: Fix ieee80211_amsdu_aggregate frag_tail bug [ Upstream commit fe94bac626d9c1c5bc98ab32707be8a9d7f8adba ] In ieee80211_amsdu_aggregate() set a pointer frag_tail point to the end of skb_shinfo(head)->frag_list, and use it to bind other skb in the end of this function. But when execute ieee80211_amsdu_aggregate() ->ieee80211_amsdu_realloc_pad()->pskb_expand_head(), the address of skb_shinfo(head)->frag_list will be changed. However, the ieee80211_amsdu_aggregate() not update frag_tail after call pskb_expand_head(). That will cause the second skb can't bind to the head skb appropriately.So we update the address of frag_tail to fix it. Fixes: 6e0456b54545 ("mac80211: add A-MSDU tx support") Signed-off-by: Chih-Kang Chang <gary.chang@xxxxxxxxxxx> Signed-off-by: Zong-Zhe Yang <kevin_yang@xxxxxxxxxxx> Signed-off-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20210830073240.12736-1-pkshih@xxxxxxxxxxx [reword comment] Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index fa09a369214d..0208f68af394 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3380,6 +3380,14 @@ static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata, if (!ieee80211_amsdu_prepare_head(sdata, fast_tx, head)) goto out; + /* If n == 2, the "while (*frag_tail)" loop above didn't execute + * and frag_tail should be &skb_shinfo(head)->frag_list. + * However, ieee80211_amsdu_prepare_head() can reallocate it. + * Reload frag_tail to have it pointing to the correct place. + */ + if (n == 2) + frag_tail = &skb_shinfo(head)->frag_list; + /* * Pad out the previous subframe to a multiple of 4 by adding the * padding to the next one, that's being added. Note that head->len