CVE-2026-72037: net: lan743x: Initialize eth_syslock spinlock before use

From: Greg Kroah-Hartman <[email protected]>

Description
===========

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

net: lan743x: Initialize eth_syslock spinlock before use

lan743x_hardware_init() calls pci11x1x_strap_get_status() during the
PCI11x1x probe sequence. That helper acquires the Ethernet subsystem
hardware lock via lan743x_hs_syslock_acquire(), which relies on
adapter->eth_syslock_spinlock to serialize access.

The spinlock is currently initialized only after the strap status is
read. With CONFIG_DEBUG_SPINLOCK enabled, taking the zeroed initialized
spinlock can trip the spinlock debug check.

Fix by initializing adapter->eth_syslock_spinlock before reading the
strap status so the probe path never attempts to lock an uninitialized
spinlock.

The Linux kernel CVE team has assigned CVE-2026-72037 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.0 with commit 46b777ad9a8c269113634cee6a380bc4e53f3964 and fixed in 6.1.178 with commit dfaefd9a7808736fcd2ed0de108f55c4badc15cc
	Issue introduced in 6.0 with commit 46b777ad9a8c269113634cee6a380bc4e53f3964 and fixed in 6.6.145 with commit 6523daa6852b1bfef32ec7a105b0217e8a115687
	Issue introduced in 6.0 with commit 46b777ad9a8c269113634cee6a380bc4e53f3964 and fixed in 6.12.97 with commit b6a93a42e0e61f0ba0005a942ee3bffb16c0574e
	Issue introduced in 6.0 with commit 46b777ad9a8c269113634cee6a380bc4e53f3964 and fixed in 6.18.40 with commit 99a6f37b113c46815deb160c5012073563679ef4
	Issue introduced in 6.0 with commit 46b777ad9a8c269113634cee6a380bc4e53f3964 and fixed in 7.1.5 with commit b99e890e6b32ffa11c145a16fefcf2c7137a9578
	Issue introduced in 6.0 with commit 46b777ad9a8c269113634cee6a380bc4e53f3964 and fixed in 7.2-rc2 with commit 39139b1c1c2b614096519b526112c726adb12ff0

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-72037
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/microchip/lan743x_main.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/dfaefd9a7808736fcd2ed0de108f55c4badc15cc
	https://git.kernel.org/stable/c/6523daa6852b1bfef32ec7a105b0217e8a115687
	https://git.kernel.org/stable/c/b6a93a42e0e61f0ba0005a942ee3bffb16c0574e
	https://git.kernel.org/stable/c/99a6f37b113c46815deb160c5012073563679ef4
	https://git.kernel.org/stable/c/b99e890e6b32ffa11c145a16fefcf2c7137a9578
	https://git.kernel.org/stable/c/39139b1c1c2b614096519b526112c726adb12ff0