CVE-2026-68317: pds_core: fix auxiliary device add/del races

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

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

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

pds_core: fix auxiliary device add/del races

Two paths add or delete the same slot (pf->vfs[vf_id].padev): a VF's
pdsc_reset_done() and the PF's devlink enable_vnet/disable_vnet handler.
They serialize on config_lock, but neither guards the slot under it
correctly.

add() registers and stores a new auxiliary device without first checking
the slot, so a second add of an already-populated slot leaks the first
device. del() makes that check outside config_lock, so two concurrent
dels can both pass it; the first clears the slot, and the second
dereferences a NULL pointer.

Check and update the slot under config_lock in both paths.

The Linux kernel CVE team has assigned CVE-2026-68317 to this issue.


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

	Issue introduced in 6.6.90 with commit 0861fccd43b8bafb533d97308862d20b7db3a2ad and fixed in 6.6.148 with commit 646b58b543f3bb1641e9123b75ff7799fe7b42f1
	Issue introduced in 6.12.28 with commit f41e27b746241e57d968d1d61c008322338ca258 and fixed in 6.12.101 with commit ef194751fed50cf3452017b63f00142a0ab40c70
	Issue introduced in 6.15 with commit b699bdc720c0255d1bb76cecba7382c1f2107af5 and fixed in 6.18.42 with commit cf0ed2ba202f5c3b300ec1bf7ff0b5d555f7d518
	Issue introduced in 6.15 with commit b699bdc720c0255d1bb76cecba7382c1f2107af5 and fixed in 7.1.6 with commit bdeab32a7a91acd295d52a2d4ab1cc3f2da5e454
	Issue introduced in 6.15 with commit b699bdc720c0255d1bb76cecba7382c1f2107af5 and fixed in 7.2-rc5 with commit bfa33cd513c7ceb93c5a4c30e5662acd73c0a916
	Issue introduced in 6.14.6 with commit fec5f7af1d5f64a38f9224cd27b274d1af55a7ed

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-2026-68317
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/net/ethernet/amd/pds_core/auxbus.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/646b58b543f3bb1641e9123b75ff7799fe7b42f1
	https://git.kernel.org/stable/c/ef194751fed50cf3452017b63f00142a0ab40c70
	https://git.kernel.org/stable/c/cf0ed2ba202f5c3b300ec1bf7ff0b5d555f7d518
	https://git.kernel.org/stable/c/bdeab32a7a91acd295d52a2d4ab1cc3f2da5e454
	https://git.kernel.org/stable/c/bfa33cd513c7ceb93c5a4c30e5662acd73c0a916