Re: [Intel-wired-lan] [PATCH v2 iwl-net] igc: don't fail igc_probe() on LED setup error

[Mor Bar-Gabay <morx.bar.gabay@intel.com>]

On 10/09/2025 16:47, Kohei Enju wrote:
> When igc_led_setup() fails, igc_probe() fails and triggers kernel panic
> in free_netdev() since unregister_netdev() is not called. [1]
> This behavior can be tested using fault-injection framework, especially
> the failslab feature. [2]
> 
> Since LED support is not mandatory, treat LED setup failures as
> non-fatal and continue probe with a warning message, consequently
> avoiding 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: Paul Menzel <pmenzel@molgen.mpg.de>
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
> Reviewed-by: Vitaly Lifshits <vitaly.lifshits@intel.com>
> Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
> ---
> Changes:
>    v1->v2:
>      - don't fail probe when led setup fails
>      - rephrase subject and commit message
>    v1: https://lore.kernel.org/intel-wired-lan/20250906055239.29396-1-enjuk@amazon.com/
> ---
>   drivers/net/ethernet/intel/igc/igc.h      |  1 +
>   drivers/net/ethernet/intel/igc/igc_main.c | 12 +++++++++---
>   2 files changed, 10 insertions(+), 3 deletions(-)
> 
Tested-by: Mor Bar-Gabay <morx.bar.gabay@intel.com>