Subject: CVE-2024-35808: md/dm-raid: don't call md_reap_sync_thread() directly

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

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

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

md/dm-raid: don't call md_reap_sync_thread() directly

Currently md_reap_sync_thread() is called from raid_message() directly
without holding 'reconfig_mutex', this is definitely unsafe because
md_reap_sync_thread() can change many fields that is protected by
'reconfig_mutex'.

However, hold 'reconfig_mutex' here is still problematic because this
will cause deadlock, for example, commit 130443d60b1b ("md: refactor
idle/frozen_sync_thread() to fix deadlock").

Fix this problem by using stop_sync_thread() to unregister sync_thread,
like md/raid did.

The Linux kernel CVE team has assigned CVE-2024-35808 to this issue.

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

	Issue introduced in 3.10 with commit be83651f0050 and fixed in 6.7.12 with commit 347dcdc15a17
	Issue introduced in 3.10 with commit be83651f0050 and fixed in 6.8.3 with commit 9e59b8d76ff5
	Issue introduced in 3.10 with commit be83651f0050 and fixed in 6.9 with commit cd32b27a66db

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-2024-35808
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/dm-raid.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/347dcdc15a1706f61aa545ae498ededdf31aeebc
	https://git.kernel.org/stable/c/9e59b8d76ff511505eb0dd1478329f09e0f04669
	https://git.kernel.org/stable/c/cd32b27a66db8776d8b8e82ec7d7dde97a8693b0