From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on sa.local.altlinux.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.1 From: Ajrat Makhmutov To: devel-kernel@lists.altlinux.org Date: Thu, 11 Jun 2026 13:44:08 +0300 Message-ID: <20260611104408.227113-1-rauty@altlinux.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <'<20260610083910.23062-1-rauty@altlinux.org>'> References: <'<20260610083910.23062-1-rauty@altlinux.org>'> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [d-kernel] [PATCH 3/2] wifi: mt76: mt7921: fix potential deadlock in mt7921_roc_abort_sync X-BeenThere: devel-kernel@lists.altlinux.org X-Mailman-Version: 2.1.12 Precedence: list Reply-To: ALT Linux kernel packages development List-Id: ALT Linux kernel packages development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Jun 2026 10:44:18 -0000 Archived-At: List-Archive: List-Post: From: Sean Wang roc_abort_sync() can deadlock with roc_work(). roc_work() holds dev->mt76.mutex, while cancel_work_sync() waits for roc_work() to finish. If the caller already owns the same mutex, both sides block and no progress is possible. This deadlock can occur during station removal when mt76_sta_state() -> mt76_sta_remove() -> mt7921_mac_sta_remove() -> mt7921_roc_abort_sync() invokes cancel_work_sync() while roc_work() is still running and holding dev->mt76.mutex. This avoids the mutex deadlock and preserves exactly-once work ownership. Fixes: 352d966126e6 ("wifi: mt76: mt7921: fix a potential association failure upon resuming") Co-developed-by: Quan Zhou Signed-off-by: Quan Zhou Signed-off-by: Sean Wang Link: https://patch.msgid.link/20260126180013.8167-1-sean.wang@kernel.org Signed-off-by: Felix Fietkau (cherry picked from commit d5059e52fd8bc624ec4255c9fa01a266513d126b) [ALT: keep del_timer_sync() instead of timer_delete_sync() — the timer API rename is not present in 6.12.y. ] --- Дополнение к ранее присланной серии из двух патчей. Саша Левин на ревью запроса в stable@ указал, что patch 2/2 (5ed54896, "fix a potential scan no APs") в одиночку вносит достижимый self-deadlock по dev->mt76.mutex: путь удаления станции идёт под этим mutex (его берёт ядровая mt76_sta_remove()), а добавленный там roc_abort_sync() делает cancel_work_sync() по roc_work(), который тоже хочет этот mutex. Этот коммит (d5059e52) — обязательное лечение, применять вместе с 2/2. Таким образом серия теперь из трёх патчей. drivers/net/wireless/mediatek/mt76/mt7921/main.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/main.c b/drivers/net/wireless/mediatek/mt76/mt7921/main.c index f2fffca868b51..99561094640f1 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7921/main.c +++ b/drivers/net/wireless/mediatek/mt76/mt7921/main.c @@ -365,12 +365,15 @@ void mt7921_roc_abort_sync(struct mt792x_dev *dev) { struct mt792x_phy *phy = &dev->phy; + if (!test_and_clear_bit(MT76_STATE_ROC, &phy->mt76->state)) + return; + del_timer_sync(&phy->roc_timer); - cancel_work_sync(&phy->roc_work); - if (test_and_clear_bit(MT76_STATE_ROC, &phy->mt76->state)) - ieee80211_iterate_interfaces(mt76_hw(dev), - IEEE80211_IFACE_ITER_RESUME_ALL, - mt7921_roc_iter, (void *)phy); + cancel_work(&phy->roc_work); + + ieee80211_iterate_interfaces(mt76_hw(dev), + IEEE80211_IFACE_ITER_RESUME_ALL, + mt7921_roc_iter, (void *)phy); } EXPORT_SYMBOL_GPL(mt7921_roc_abort_sync); -- 2.50.1