Re: [PATCH v1 iwl-net] igc: unregister netdev when igc_led_setup() fails in igc_probe()

[Kurt Kanzenbach <kurt@linutronix.de>]

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On Sat Sep 06 2025, Kohei Enju wrote:
> Currently igc_probe() doesn't unregister netdev when igc_led_setup()
> fails, causing BUG_ON() in free_netdev() and then kernel panics. [1]
>
> This behavior can be tested using fault-injection framework. I used the
> failslab feature to test the issue. [2]
>
> Call unregister_netdev() when igc_led_setup() fails to avoid the kernel
> panic.
>
> [1]
>  kernel BUG at net/core/dev.c:12047!
>  Oops: invalid opcode: 0000 [#1] SMP NOPTI
>  CPU: 0 UID: 0 PID: 937 Comm: repro-igc-led-e Not tainted 6.17.0-rc4-enjuk-tnguy-00865-gc4940196ab02 #64 PREEMPT(voluntary)
>  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
>  RIP: 0010:free_netdev+0x278/0x2b0
>  [...]
>  Call Trace:
>   <TASK>
>   igc_probe+0x370/0x910
>   local_pci_probe+0x3a/0x80
>   pci_device_probe+0xd1/0x200
>  [...]
>
> [2]
>  #!/bin/bash -ex
>
>  FAILSLAB_PATH=/sys/kernel/debug/failslab/
>  DEVICE=0000:00:05.0
>  START_ADDR=$(grep " igc_led_setup" /proc/kallsyms \
>          | awk '{printf("0x%s", $1)}')
>  END_ADDR=$(printf "0x%x" $((START_ADDR + 0x100)))
>
>  echo $START_ADDR > $FAILSLAB_PATH/require-start
>  echo $END_ADDR > $FAILSLAB_PATH/require-end
>  echo 1 > $FAILSLAB_PATH/times
>  echo 100 > $FAILSLAB_PATH/probability
>  echo N > $FAILSLAB_PATH/ignore-gfp-wait
>
>  echo $DEVICE > /sys/bus/pci/drivers/igc/bind
>
> Fixes: ea578703b03d ("igc: Add support for LEDs on i225/i226")
> Signed-off-by: Kohei Enju <enjuk@amazon.com>

Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>

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