From: Deren Wu deren.wu@mediatek.com

Add a NULL check for msta->vif before accessing its members to prevent a kernel panic in AP mode deployment. This also fix the issue reported in [1].

The crash occurs when this function is triggered before the station is fully initialized. The call trace shows a page fault at mt7925_sta_set_decap_offload() due to accessing resources when msta->vif is NULL.

Fix this by adding an early return if msta->vif is NULL and also check wcid.sta is ready. This ensures we only proceed with decap offload configuration when the station's state is properly initialized.

[14739.655703] Unable to handle kernel paging request at virtual address ffffffffffffffa0 [14739.811820] CPU: 0 UID: 0 PID: 895854 Comm: hostapd Tainted: G [14739.821394] Tainted: [C]=CRAP, [O]=OOT_MODULE [14739.825746] Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT) [14739.831577] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [14739.838538] pc : mt7925_sta_set_decap_offload+0xc0/0x1b8 [mt7925_common] [14739.845271] lr : mt7925_sta_set_decap_offload+0x58/0x1b8 [mt7925_common] [14739.851985] sp : ffffffc085efb500 [14739.855295] x29: ffffffc085efb500 x28: 0000000000000000 x27: ffffff807803a158 [14739.862436] x26: ffffff8041ececb8 x25: 0000000000000001 x24: 0000000000000001 [14739.869577] x23: 0000000000000001 x22: 0000000000000008 x21: ffffff8041ecea88 [14739.876715] x20: ffffff8041c19ca0 x19: ffffff8078031fe0 x18: 0000000000000000 [14739.883853] x17: 0000000000000000 x16: ffffffe2aeac1110 x15: 000000559da48080 [14739.890991] x14: 0000000000000001 x13: 0000000000000000 x12: 0000000000000000 [14739.898130] x11: 0a10020001008e88 x10: 0000000000001a50 x9 : ffffffe26457bfa0 [14739.905269] x8 : ffffff8042013bb0 x7 : ffffff807fb6cbf8 x6 : dead000000000100 [14739.912407] x5 : dead000000000122 x4 : ffffff80780326c8 x3 : 0000000000000000 [14739.919546] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffffff8041ececb8 [14739.926686] Call trace: [14739.929130] mt7925_sta_set_decap_offload+0xc0/0x1b8 [mt7925_common] [14739.935505] ieee80211_check_fast_rx+0x19c/0x510 [mac80211] [14739.941344] _sta_info_move_state+0xe4/0x510 [mac80211] [14739.946860] sta_info_move_state+0x1c/0x30 [mac80211] [14739.952116] sta_apply_auth_flags.constprop.0+0x90/0x1b0 [mac80211] [14739.958708] sta_apply_parameters+0x234/0x5e0 [mac80211] [14739.964332] ieee80211_add_station+0xdc/0x190 [mac80211] [14739.969950] nl80211_new_station+0x46c/0x670 [cfg80211] [14739.975516] genl_family_rcv_msg_doit+0xdc/0x150 [14739.980158] genl_rcv_msg+0x218/0x298 [14739.983830] netlink_rcv_skb+0x64/0x138 [14739.987670] genl_rcv+0x40/0x60 [14739.990816] netlink_unicast+0x314/0x380 [14739.994742] netlink_sendmsg+0x198/0x3f0 [14739.998664] __sock_sendmsg+0x64/0xc0 [14740.002324] ____sys_sendmsg+0x260/0x298 [14740.006242] ___sys_sendmsg+0xb4/0x110

Cc: stable@vger.kernel.org Link: https://github.com/morrownr/USB-WiFi/issues/603 [1] Fixes: b859ad65309a ("wifi: mt76: mt7925: add link handling in mt7925_sta_set_decap_offload") Signed-off-by: Deren Wu deren.wu@mediatek.com --- drivers/net/wireless/mediatek/mt76/mt7925/main.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c index 94b0099dcd41..320011fc3073 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c +++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c @@ -1603,6 +1603,9 @@ static void mt7925_sta_set_decap_offload(struct ieee80211_hw *hw, unsigned long valid = mvif->valid_links; u8 i;

+ if (!msta->vif) + return; + mt792x_mutex_acquire(dev);

valid = ieee80211_vif_is_mld(vif) ? mvif->valid_links : BIT(0); @@ -1617,6 +1620,9 @@ static void mt7925_sta_set_decap_offload(struct ieee80211_hw *hw, else clear_bit(MT_WCID_FLAG_HDR_TRANS, &mlink->wcid.flags);

+ if (!mlink->wcid.sta) + continue; + mt7925_mcu_wtbl_update_hdr_trans(dev, vif, sta, i); }