diff options
| author | Rajat Gupta <rajat.gupta@oss.qualcomm.com> | 2026-05-06 21:35:31 -0700 |
|---|---|---|
| committer | Felix Fietkau <nbd@nbd.name> | 2026-06-09 10:15:20 +0000 |
| commit | 7fae097aa9a56c30febf539d72ef3773165d3aa3 (patch) | |
| tree | dd2715035b4623b3446765740a384e41288d41cc | |
| parent | 37d65384aa6f9cbe45f4052b13b378af1aab3e95 (diff) | |
wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link
mt76_put_vif_phy_link() frees the offchannel mlink with plain kfree()
after rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents
future RCU readers from obtaining the pointer -- it does not wait for
existing readers that already hold it via rcu_dereference.
The TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink->wcid
and mlink->idx under rcu_read_lock. If a TX softirq obtained the pointer
via rcu_dereference just before the NULL assignment, it will dereference
freed memory after the kfree.
struct mt76_vif_link already contains an rcu_head field that is unused at
this free site -- a developer oversight, since the adjacent
kfree_rcu_mightsleep call for rx_sc in the same function shows the
pattern was understood.
Replace kfree(mlink) with kfree_rcu(mlink, rcu_head).
Fixes: a8f424c1287c ("wifi: mt76: add multi-radio remain_on_channel functions")
Signed-off-by: Rajat Gupta <rajat.gupta@oss.qualcomm.com>
Link: https://patch.msgid.link/20260507043531.492-1-rajat.gupta@oss.qualcomm.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>
| -rw-r--r-- | drivers/net/wireless/mediatek/mt76/channel.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/wireless/mediatek/mt76/channel.c b/drivers/net/wireless/mediatek/mt76/channel.c index 05eee64706ea..6edcb3b8f279 100644 --- a/drivers/net/wireless/mediatek/mt76/channel.c +++ b/drivers/net/wireless/mediatek/mt76/channel.c @@ -307,7 +307,7 @@ void mt76_put_vif_phy_link(struct mt76_phy *phy, struct ieee80211_vif *vif, rcu_assign_pointer(mvif->offchannel_link, NULL); dev->drv->vif_link_remove(phy, vif, &vif->bss_conf, mlink); - kfree(mlink); + kfree_rcu(mlink, rcu_head); } void mt76_roc_complete(struct mt76_phy *phy) |