6.6-stable review patch. If anyone has any objections, please let me know.
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From: Andy Strohman andrew@andrewstrohman.com
[ Upstream commit 3aaa1a5a9a2ceeb32afa6ea4110a92338a863c33 ]
With change (wifi: mac80211: fix receiving A-MSDU frames on mesh interfaces), a non-zero TID assignment is lost during slow path mesh forwarding.
Prior to this change, ieee80211_rx_h_mesh_fwding() left the TID intact in the header.
As a result of this header corruption, packets belonging to non-zero TIDs will get treating as belonging TID 0 by functions such as ieee80211_get_tid(). While this miscategorization by itself is an issue, there are additional ramifications due to the fact that skb->priority still reflects the mesh forwarded packet's ingress (correct) TID.
The mt7915 driver inspects the TID recorded within skb->priority and relays this to the hardware/radio during TX. The radio firmware appears to react to this by changing the sequence control header, but it does not also ensure/correct the TID in the QoS control header. As a result, the receiver will see packets with sequence numbers corresponding to the wrong TID. The receiver of the forwarded packet will see TID 0 in QoS control but a sequence number corresponding to the correct (different) TID in sequence control. This causes data stalls for TID 0 until the TID 0 sequence number advances past what the receiver believes it should be due to this bug.
Mesh routing mpath changes cause a brief transition from fast path forwarding to slow path forwarding. Since this bug only affects the slow path forwarding, mpath changes bring opportunity for the bug to be triggered. In the author's case, he was experiencing TID 0 data stalls after mpath changes on an intermediate mesh node.
These observed stalls may be specific to mediatek radios. But the inconsistency between the packet header and skb->priority may cause problems for other drivers as well. Regardless if this causes connectivity issues on other radios, this change is necessary in order transmit (forward) the packet on the correct TID and to have a consistent view a packet's TID within mac80211.
Fixes: 986e43b19ae9 ("wifi: mac80211: fix receiving A-MSDU frames on mesh interfaces") Signed-off-by: Andy Strohman andrew@andrewstrohman.com Link: https://patch.msgid.link/20250107104431.446775-1-andrew@andrewstrohman.com Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/mac80211/rx.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 604863cebc198..5eb233f619817 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2957,6 +2957,7 @@ ieee80211_rx_mesh_data(struct ieee80211_sub_if_data *sdata, struct sta_info *sta }
IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_frames); + ieee80211_set_qos_hdr(sdata, fwd_skb); ieee80211_add_pending_skb(local, fwd_skb);
rx_accept: