CVE-2025-39956

In the Linux kernel, the following vulnerability has been resolved:

igc: don't fail igc_probe() on LED setup error

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