CVE-2026-64587: net: ethernet: arc: emac: quiesce interrupts before requesting IRQ

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

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

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

net: ethernet: arc: emac: quiesce interrupts before requesting IRQ

Normal RX/TX interrupts are enabled later, in arc_emac_open(), so probe
should not see interrupt delivery in the usual case. However, hardware may
still present stale or latched interrupt status left by firmware or the
bootloader.

If probe later unwinds after devm_request_irq() has installed the handler,
such a stale interrupt can still reach arc_emac_intr() during teardown and
race with release of the associated net_device.

Avoid that window by putting the device into a known quiescent state before
requesting the IRQ: disable all EMAC interrupt sources and clear any
pending EMAC interrupt status bits. This keeps the change hardware-focused
and minimal, while preventing spurious IRQ delivery from leftover state.

The Linux kernel CVE team has assigned CVE-2026-64587 to this issue.


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

	Issue introduced in 3.11 with commit e4f2379db6c6823c5d4a4c2c912df00c65de51d7 and fixed in 5.10.253 with commit abd338da658d7faa8e26cfefc8f83f0066707564
	Issue introduced in 3.11 with commit e4f2379db6c6823c5d4a4c2c912df00c65de51d7 and fixed in 5.15.203 with commit 5f29dd540fe5ea3c826fc8ec759ba488b31f9707
	Issue introduced in 3.11 with commit e4f2379db6c6823c5d4a4c2c912df00c65de51d7 and fixed in 6.1.167 with commit 6fc7449773748c7b904235a09a67054d78ab1172
	Issue introduced in 3.11 with commit e4f2379db6c6823c5d4a4c2c912df00c65de51d7 and fixed in 6.6.130 with commit 81431da777924dddaefa5c9b0ca9da4a93f9df96
	Issue introduced in 3.11 with commit e4f2379db6c6823c5d4a4c2c912df00c65de51d7 and fixed in 6.12.78 with commit d0f2386f529807826e7404d40a245ee428f89f62
	Issue introduced in 3.11 with commit e4f2379db6c6823c5d4a4c2c912df00c65de51d7 and fixed in 6.18.19 with commit 8efd5dcd31e22a9308b16b107a052fcd568c0a99
	Issue introduced in 3.11 with commit e4f2379db6c6823c5d4a4c2c912df00c65de51d7 and fixed in 6.19.9 with commit 8f9adb3605e36f75639de529bb3d66e94194a388
	Issue introduced in 3.11 with commit e4f2379db6c6823c5d4a4c2c912df00c65de51d7 and fixed in 7.0 with commit 2503d08f8a2de618e5c3a8183b250ff4a2e2d52c

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-2026-64587
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/arc/emac_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/abd338da658d7faa8e26cfefc8f83f0066707564
	https://git.kernel.org/stable/c/5f29dd540fe5ea3c826fc8ec759ba488b31f9707
	https://git.kernel.org/stable/c/6fc7449773748c7b904235a09a67054d78ab1172
	https://git.kernel.org/stable/c/81431da777924dddaefa5c9b0ca9da4a93f9df96
	https://git.kernel.org/stable/c/d0f2386f529807826e7404d40a245ee428f89f62
	https://git.kernel.org/stable/c/8efd5dcd31e22a9308b16b107a052fcd568c0a99
	https://git.kernel.org/stable/c/8f9adb3605e36f75639de529bb3d66e94194a388
	https://git.kernel.org/stable/c/2503d08f8a2de618e5c3a8183b250ff4a2e2d52c