CVE-2026-23463: soc: fsl: qbman: fix race condition in qman_destroy_fq

CVE-2026-23463: soc: fsl: qbman: fix race condition in qman_destroy_fq

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

soc: fsl: qbman: fix race condition in qman_destroy_fq

When QMAN_FQ_FLAG_DYNAMIC_FQID is set, there's a race condition between
fq_table[fq->idx] state and freeing/allocating from the pool and
WARN_ON(fq_table[fq->idx]) in qman_create_fq() gets triggered.

Indeed, we can have:
         Thread A                             Thread B
    qman_destroy_fq()                    qman_create_fq()
      qman_release_fqid()
        qman_shutdown_fq()
        gen_pool_free()
           -- At this point, the fqid is available again --
                                           qman_alloc_fqid()
           -- so, we can get the just-freed fqid in thread B --
                                           fq->fqid = fqid;
                                           fq->idx = fqid * 2;
                                           WARN_ON(fq_table[fq->idx]);
                                           fq_table[fq->idx] = fq;
     fq_table[fq->idx] = NULL;

And adding some logs between qman_release_fqid() and
fq_table[fq->idx] = NULL makes the WARN_ON() trigger a lot more.

To prevent that, ensure that fq_table[fq->idx] is set to NULL before
gen_pool_free() is called by using smp_wmb().

The Linux kernel CVE team has assigned CVE-2026-23463 to this issue.


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

	Issue introduced in 4.9 with commit c535e923bb97a4b361e89a6383693482057f8b0c and fixed in 6.1.167 with commit 9e3d47904b8153c8c3ad2f9b66d5008aad677aa8
	Issue introduced in 4.9 with commit c535e923bb97a4b361e89a6383693482057f8b0c and fixed in 6.6.130 with commit d21923a8059fa896bfef016f55dd769299335cb4
	Issue introduced in 4.9 with commit c535e923bb97a4b361e89a6383693482057f8b0c and fixed in 6.12.78 with commit 751f60bd48edaf03f9d84ab09e5ce6705757d50f
	Issue introduced in 4.9 with commit c535e923bb97a4b361e89a6383693482057f8b0c and fixed in 6.18.20 with commit 85dbbf7dc88b0a54f2e334daedf6f3f31fd004fa
	Issue introduced in 4.9 with commit c535e923bb97a4b361e89a6383693482057f8b0c and fixed in 6.19.10 with commit 265e56714635c5dd1e5964bfd97fa6e73f62cde5
	Issue introduced in 4.9 with commit c535e923bb97a4b361e89a6383693482057f8b0c and fixed in 7.0-rc5 with commit 014077044e874e270ec480515edbc1cadb976cf2

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-2026-23463
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/soc/fsl/qbman/qman.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/9e3d47904b8153c8c3ad2f9b66d5008aad677aa8
	https://git.kernel.org/stable/c/d21923a8059fa896bfef016f55dd769299335cb4
	https://git.kernel.org/stable/c/751f60bd48edaf03f9d84ab09e5ce6705757d50f
	https://git.kernel.org/stable/c/85dbbf7dc88b0a54f2e334daedf6f3f31fd004fa
	https://git.kernel.org/stable/c/265e56714635c5dd1e5964bfd97fa6e73f62cde5
	https://git.kernel.org/stable/c/014077044e874e270ec480515edbc1cadb976cf2