Files
mt76/mt7921
Devin WittmayerandFelix Fietkau d367ee6d72 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: [email protected]
Signed-off-by: Devin Wittmayer <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Felix Fietkau <[email protected]>
2026-07-21 10:30:02 +02:00
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