From: Devin Wittmayer Date: Sat, 27 Jun 2026 19:13:34 +0000 (-0700) Subject: wifi: mt76: mt7921: drop TXRX_NOTIFY on non-mmio buses X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=da4082e91acabc1498611ed8ccc53f0610baefc6;p=thirdparty%2Fkernel%2Flinux.git wifi: mt76: mt7921: drop TXRX_NOTIFY on non-mmio buses PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7921_rx_check() and mt7921_queue_rx_skb() dispatch it to mt7921_mac_tx_free() on every bus. mt7921_mac_tx_free() cleans the DMA tx queues with mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the mmio queue ops implement that callback; on USB and SDIO it is NULL, so a TXRX_NOTIFY there calls a NULL pointer in the RX worker: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:0x0 Call Trace: mt7921_mac_tx_free+0x64/0x310 [mt7921_common] mt7921_rx_check+0x5f/0xf0 [mt7921_common] mt76u_rx_worker+0x1b9/0x620 [mt76_usb] Drop the event on non-mmio buses via mt76_is_mmio(), as in commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for non-mmio devices"). Fixes: 48fab5bbef40 ("mt76: mt7921: introduce mt7921s support") Cc: stable@vger.kernel.org Signed-off-by: Devin Wittmayer Link: https://patch.msgid.link/20260627191336.20223-2-lucid_duck@justthetip.ca Signed-off-by: Felix Fietkau --- diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c index 1c2377d0a53d3..f7d54472da1b1 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c +++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c @@ -570,8 +570,9 @@ bool mt7921_rx_check(struct mt76_dev *mdev, void *data, int len) switch (type) { case PKT_TYPE_TXRX_NOTIFY: - /* PKT_TYPE_TXRX_NOTIFY can be received only by mmio devices */ - mt7921_mac_tx_free(dev, data, len); /* mmio */ + if (!mt76_is_mmio(mdev)) + return false; + mt7921_mac_tx_free(dev, data, len); return false; case PKT_TYPE_TXS: for (rxd += 2; rxd + 8 <= end; rxd += 8) @@ -600,7 +601,10 @@ void mt7921_queue_rx_skb(struct mt76_dev *mdev, enum mt76_rxq_id q, switch (type) { case PKT_TYPE_TXRX_NOTIFY: - /* PKT_TYPE_TXRX_NOTIFY can be received only by mmio devices */ + if (!mt76_is_mmio(mdev)) { + napi_consume_skb(skb, 1); + break; + } mt7921_mac_tx_free(dev, skb->data, skb->len); napi_consume_skb(skb, 1); break;