> -----Original Message----- > From: Ping-Ke Shih [mailto:pkshih@xxxxxxxxxxx] > Sent: Monday, August 30, 2021 2:17 PM > To: johannes@xxxxxxxxxxxxxxxx > Cc: linux-wireless@xxxxxxxxxxxxxxx; nbd@xxxxxxxx; Gary Chang; Kevin Yang > Subject: [PATCH v2] mac80211: Fix ieee80211_amsdu_aggregate frag_tail bug > > From: Chih-Kang Chang <gary.chang@xxxxxxxxxxx> > > 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> > --- > v2: an alternative fix to prevent iterating fragment twice. > --- > net/mac80211/tx.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c > index 2d1193ed3eb5..fb5e43489b62 100644 > --- a/net/mac80211/tx.c > +++ b/net/mac80211/tx.c > @@ -3380,6 +3380,13 @@ static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata, > if (!ieee80211_amsdu_prepare_head(sdata, fast_tx, head)) > goto out; > > + /* While n == 2, frag_tail should be the address of head's frag_list. > + * However, head probably re-alloc after ieee80211_amsdu_prepare_head. > + * So, re-assign frag_tail again to make sure the correctness. > + */ > + if (n == 2) > + frag_tail = &skb_shinfo(head)->frag_list; > + I mess up the coding style and fix it by v3 [1]. Please ignore this patch. [1] https://lore.kernel.org/linux-wireless/20210830073240.12736-1-pkshih@xxxxxxxxxxx/T/#u -- Ping-Ke
