diff options
| author | Arjan van de Ven <arjan@linux.intel.com> | 2026-05-04 07:51:06 -0700 |
|---|---|---|
| committer | Felix Fietkau <nbd@nbd.name> | 2026-06-09 10:15:20 +0000 |
| commit | 351dd7d2c80d23e56dcce6faa4e62bea5b0877c7 (patch) | |
| tree | 1b91bbbcf9587bfbcfecfaeb3c6163409876b8e5 | |
| parent | 346dac35b1384af9338b34b6835e82e634ea4d2c (diff) | |
wifi: mt76: mt7921/mt7925: fix NULL dereference in CSA beacon
This patch is based on a BUG as reported by Bongani Hlope at
https://lore.kernel.org/all/20260502125824.425d7159@bongani-mini.home.org.za/
When a channel-switch announcement (CSA) beacon is received,
cfg80211 queues a wiphy work item that eventually calls
mt7921_channel_switch_rx_beacon(). If the station disconnects
(or the channel context is otherwise torn down) between the
time the work is queued and the time it runs, the driver's
dev->new_ctx pointer can already have been cleared to NULL.
mt7921_channel_switch_rx_beacon() then dereferences new_ctx
unconditionally, triggering a NULL pointer dereference at
address 0x0:
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:mt7921_channel_switch_rx_beacon+0x1f/0x100 [mt7921_common]
The same missing guard exists in mt7925_channel_switch_rx_beacon(),
which shares the same code pattern introduced by the same commit.
Add an early-return NULL check for dev->new_ctx in both
mt7921_channel_switch_rx_beacon() and
mt7925_channel_switch_rx_beacon(). When new_ctx is NULL there is
no pending channel switch to process, so returning immediately is
the correct and safe action.
Fixes: 8aa2f59260eb ("wifi: mt76: mt7921: introduce CSA support")
Reported-by: Bongani Hlope <developer@hlope.org.za>
Oops-Analysis: http://oops.fenrus.org/reports/lkml/20260502125824.425d7159@bongani-mini.home.org.za/report.html
Link: https://lore.kernel.org/all/20260502125824.425d7159@bongani-mini.home.org.za/
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: linux-wireless@vger.kernel.org
Cc: linux-mediatek@lists.infradead.org
Cc: Felix Fietkau <nbd@nbd.name>
Cc: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: Ryder Lee <ryder.lee@mediatek.com>
Link: https://patch.msgid.link/20260504145107.1329197-1-arjan@linux.intel.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>
| -rw-r--r-- | drivers/net/wireless/mediatek/mt76/mt7921/main.c | 3 | ||||
| -rw-r--r-- | drivers/net/wireless/mediatek/mt76/mt7925/main.c | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/main.c b/drivers/net/wireless/mediatek/mt76/mt7921/main.c index 3d74fabe7408..a326f4c95c7c 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7921/main.c +++ b/drivers/net/wireless/mediatek/mt76/mt7921/main.c @@ -1508,6 +1508,9 @@ static void mt7921_channel_switch_rx_beacon(struct ieee80211_hw *hw, struct mt792x_vif *mvif = (struct mt792x_vif *)vif->drv_priv; u16 beacon_interval = vif->bss_conf.beacon_int; + if (!dev->new_ctx) + return; + if (cfg80211_chandef_identical(&chsw->chandef, &dev->new_ctx->def) && chsw->count) { diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c index 73d3722739d0..ec6eb2897aec 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c +++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c @@ -2400,6 +2400,9 @@ static void mt7925_channel_switch_rx_beacon(struct ieee80211_hw *hw, if (ieee80211_vif_is_mld(vif)) return; + if (!dev->new_ctx) + return; + beacon_interval = vif->bss_conf.beacon_int; if (cfg80211_chandef_identical(&chsw->chandef, |