Subject: CVE-2024-38384: blk-cgroup: fix list corruption from reorder of WRITE ->lqueued

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

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

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

blk-cgroup: fix list corruption from reorder of WRITE ->lqueued

__blkcg_rstat_flush() can be run anytime, especially when blk_cgroup_bio_start
is being executed.

If WRITE of `->lqueued` is re-ordered with READ of 'bisc->lnode.next' in
the loop of __blkcg_rstat_flush(), `next_bisc` can be assigned with one
stat instance being added in blk_cgroup_bio_start(), then the local
list in __blkcg_rstat_flush() could be corrupted.

Fix the issue by adding one barrier.

The Linux kernel CVE team has assigned CVE-2024-38384 to this issue.

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

	Issue introduced in 6.2 with commit 3b8cc6298724 and fixed in 6.6.33 with commit 714e59b5456e
	Issue introduced in 6.2 with commit 3b8cc6298724 and fixed in 6.9.4 with commit 785298ab6b80
	Issue introduced in 6.2 with commit 3b8cc6298724 and fixed in 6.10 with commit d0aac2363549

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-2024-38384
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:
	block/blk-cgroup.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/714e59b5456e4d6e4295a9968c564abe193f461c
	https://git.kernel.org/stable/c/785298ab6b802afa75089239266b6bbea590809c
	https://git.kernel.org/stable/c/d0aac2363549e12cc79b8e285f13d5a9f42fd08e