CVE-2025-39956

Summary

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

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/bec504867acc7315de9cd96ef9161fa52a25abe8
• https://git.kernel.org/stable/c/f05e82d8553232cef150a6dbb70ed67d162abb2b
• https://git.kernel.org/stable/c/528eb4e19ec0df30d0c9ae4074ce945667dde919

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