Devin Wittmayer ef2ee5f820 wifi: mt76: mt7921: drop TXRX_NOTIFY on non-mmio buses
commit da4082e91a upstream.

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 5683e1488a ("wifi: mt76: connac: do not check WED status for
non-mmio devices").

Fixes: 48fab5bbef ("mt76: mt7921: introduce mt7921s support")
Cc: stable@vger.kernel.org
Signed-off-by: Devin Wittmayer <lucid_duck@justthetip.ca>
Link: https://patch.msgid.link/20260627191336.20223-2-lucid_duck@justthetip.ca
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-03 11:15:27 +02:00
2026-07-24 16:03:06 +02:00
2026-05-23 13:03:09 +02:00
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2026-05-23 13:03:09 +02:00
2026-07-30 13:02:12 +02:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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