CVE-2026-74397: IB/mlx5: Fix transport-domain rollback and initialize lb mutex earlier

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

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

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

IB/mlx5: Fix transport-domain rollback and initialize lb mutex earlier

mlx5_ib_alloc_transport_domain() allocates a transport domain and then
may fail in mlx5_ib_enable_lb(). In that case, the allocated TD is leaked.

Fix this by deallocating the TD when mlx5_ib_enable_lb() returns an
error. Also return 0 explicitly in the no-loopback-capability success
branch, and move dev->lb.mutex initialization to mlx5_ib_stage_init_init().

The Linux kernel CVE team has assigned CVE-2026-74397 to this issue.


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

	Issue introduced in 4.5 with commit 146d2f1af3245a10b13eef263687e54f4e253d1d and fixed in 6.6.145 with commit 2c3b2667dad69d56774b79db763acb3a1bee0fc0
	Issue introduced in 4.5 with commit 146d2f1af3245a10b13eef263687e54f4e253d1d and fixed in 6.12.97 with commit 37fc3cc0f924fd8d0f0cf87b92672dec75a32e57
	Issue introduced in 4.5 with commit 146d2f1af3245a10b13eef263687e54f4e253d1d and fixed in 6.18.40 with commit 65e344925fa30abf50c8de8c150b397715fa2066
	Issue introduced in 4.5 with commit 146d2f1af3245a10b13eef263687e54f4e253d1d and fixed in 7.1.5 with commit f88e12c95fc19f719e06ca1e9eb20fdad68ef61a
	Issue introduced in 4.5 with commit 146d2f1af3245a10b13eef263687e54f4e253d1d and fixed in 7.2-rc1 with commit e79389115b9d27287ff6230a9750675106ed7668

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-2026-74397
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/infiniband/hw/mlx5/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/2c3b2667dad69d56774b79db763acb3a1bee0fc0
	https://git.kernel.org/stable/c/37fc3cc0f924fd8d0f0cf87b92672dec75a32e57
	https://git.kernel.org/stable/c/65e344925fa30abf50c8de8c150b397715fa2066
	https://git.kernel.org/stable/c/f88e12c95fc19f719e06ca1e9eb20fdad68ef61a
	https://git.kernel.org/stable/c/e79389115b9d27287ff6230a9750675106ed7668