openwrt / openwrt/mt76

mt7921u: crash upon disconnect if firmware was not available

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Dominant language
C
Stars
888
Forks
436
PR merge metrics
No merged PRs in 30d

Description

Noticed because of https://github.com/openwrt/openwrt/pull/11231

kern.info kernel: [   15.037454] mt7603e 0000:02:00.0: firmware init done
kern.warn kernel: [   15.741659] mt7921u 1-2:1.3: Direct firmware load for mediatek/WIFI_MT7961_patch_mcu_1_2_hdr.bin failed with error -2

kern.info kernel: [  872.320223] usb 1-2: USB disconnect, device number 2
kern.alert kernel: [  872.334263] CPU 0 Unable to handle kernel paging request at virtual address 00000004, epc == 82f80c60, ra == 82f80c58

The crash doesn't occur if the firmware is present.

Version: 4a27f23fc4f22510db81513680666be7e72ccb61

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the mt7921u USB disconnect after the firmware load fails with error -2, using the kernel log sequence in the issue. Trace the disconnect handling for this failure state and verify that removing the device no longer causes the kernel paging fault.

Written by the indexing model from the issue text.

Assessment

Tech stack
c, linux
Domain
networking, operating-systems
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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