FAILED: patch "[PATCH] wifi: mt76: mt7996: unlink TWT flow if the MCU rejects the" failed to apply to 6.6-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 022f5f8b7a0580da50fcbc34da853d03d4321fe2
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026110430-vagueness-punctuate-be5b@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 022f5f8b7a0580da50fcbc34da853d03d4321fe2 Mon Sep 17 00:00:00 2001
From: Zhao Li <enderaoelyther@gmail.com>
Date: Tue, 25 Aug 2026 19:26:20 +0800
Subject: [PATCH] wifi: mt76: mt7996: unlink TWT flow if the MCU rejects the
 agreement

mt7996_mac_add_twt_setup() links a new flow into dev->twt_list before
asking the MCU to add the agreement, but exits without unlinking the flow
if the request fails. The flow-ID and table masks are only committed
after MCU success, so the still-linked flow is invisible to the
mask-gated teardown paths.

If the station retries the setup, the same slot is cleared and its
embedded list node reinitialized while it is still linked, corrupting
dev->twt_list. If the station disassociates instead, teardown skips the
flow and station storage can be freed while the node remains linked. A
later scheduling or debugfs twt_stats walk can then dereference the
freed flow, resulting in a use-after-free.

Unlink the flow when the MCU rejects the agreement. This restores the
list to its pre-request state while leaving the unchanged mask and
agreement accounting untouched.

Fixes: 98686cd21624 ("wifi: mt76: mt7996: add driver for MediaTek Wi-Fi 7 (802.11be) devices")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20260729173632.14387-3-enderaoelyther@gmail.com/
Assisted-by: Codex:gpt-5.6-sol
Assisted-by: Kimi:K3
Signed-off-by: Zhao Li <enderaoelyther@gmail.com>
Link: https://patch.msgid.link/20260825112620.97568-1-enderaoelyther@gmail.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
index 898cd9b8ff96..a8c4f629109b 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
@@ -3288,8 +3288,10 @@ void mt7996_mac_add_twt_setup(struct ieee80211_hw *hw,
 	flow->tsf = le64_to_cpu(twt_agrt->twt);
 
 	if (mt7996_mcu_twt_agrt_update(dev, &msta->vif->deflink, flow,
-				       MCU_TWT_AGRT_ADD))
+				       MCU_TWT_AGRT_ADD)) {
+		list_del(&flow->list);
 		goto unlock;
+	}
 
 	setup_cmd = TWT_SETUP_CMD_ACCEPT;
 	dev->twt.table_mask |= BIT(table_id);