CVE-2026-74374: md/raid1,raid10: fix error-path detection with md_cloned_bio()

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

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

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

md/raid1,raid10: fix error-path detection with md_cloned_bio()

Detect the error path using md_cloned_bio() instead of relying
on r1_bio in raid1 or r10_bio->read_slot in raid10, which may be
NULL or -1 after splitting and resubmitting a failed bio.

As a result, the error path may not be recognized and memory
allocations can incorrectly use GFP_NOIO instead of
(GFP_NOIO | __GFP_HIGH), which can lead to a deadlock under
memory pressure.

The Linux kernel CVE team has assigned CVE-2026-74374 to this issue.


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

	Issue introduced in 4.12 with commit 689389a06ce79fdced85b5115717f71c71e623e0 and fixed in 7.1.5 with commit 20fb582c92fd64e5c8bd83c6176264b2794603b7
	Issue introduced in 4.12 with commit 689389a06ce79fdced85b5115717f71c71e623e0 and fixed in 7.2-rc1 with commit 811545e0926d02a6a0b1a1258bb5544777c164d4

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-2026-74374
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/md/raid1.c
	drivers/md/raid10.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/20fb582c92fd64e5c8bd83c6176264b2794603b7
	https://git.kernel.org/stable/c/811545e0926d02a6a0b1a1258bb5544777c164d4