linux-cve-announce - CVE-2025-21732: RDMA/mlx5: Fix a race for an ODP MR which leads to CQE with error

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Message-ID: <2025022658-CVE-2025-21732-e800@gregkh>
Date: Wed, 26 Feb 2025 18:11:14 -0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2025-21732: RDMA/mlx5: Fix a race for an ODP MR which leads to CQE with error

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

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

RDMA/mlx5: Fix a race for an ODP MR which leads to CQE with error

This patch addresses a race condition for an ODP MR that can result in a
CQE with an error on the UMR QP.

During the __mlx5_ib_dereg_mr() flow, the following sequence of calls
occurs:

mlx5_revoke_mr()
 mlx5r_umr_revoke_mr()
 mlx5r_umr_post_send_wait()

At this point, the lkey is freed from the hardware's perspective.

However, concurrently, mlx5_ib_invalidate_range() might be triggered by
another task attempting to invalidate a range for the same freed lkey.

This task will:
 - Acquire the umem_odp->umem_mutex lock.
 - Call mlx5r_umr_update_xlt() on the UMR QP.
 - Since the lkey has already been freed, this can lead to a CQE error,
   causing the UMR QP to enter an error state [1].

To resolve this race condition, the umem_odp->umem_mutex lock is now also
acquired as part of the mlx5_revoke_mr() scope.  Upon successful revoke,
we set umem_odp->private which points to that MR to NULL, preventing any
further invalidation attempts on its lkey.

[1] From dmesg:

   infiniband rocep8s0f0: dump_cqe:277:(pid 0): WC error: 6, Message: memory bind operation error
   cqe_dump: 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   cqe_dump: 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   cqe_dump: 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   cqe_dump: 00000030: 00 00 00 00 08 00 78 06 25 00 11 b9 00 0e dd d2

   WARNING: CPU: 15 PID: 1506 at drivers/infiniband/hw/mlx5/umr.c:394 mlx5r_umr_post_send_wait+0x15a/0x2b0 [mlx5_ib]
   Modules linked in: ip6table_mangle ip6table_natip6table_filter ip6_tables iptable_mangle xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi rdma_cm iw_cm ib_umad ib_ipoib ib_cm mlx5_ib ib_uverbs ib_core fuse mlx5_core
   CPU: 15 UID: 0 PID: 1506 Comm: ibv_rc_pingpong Not tainted 6.12.0-rc7+ #1626
   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
   RIP: 0010:mlx5r_umr_post_send_wait+0x15a/0x2b0 [mlx5_ib]
   [..]
   Call Trace:
   <TASK>
   mlx5r_umr_update_xlt+0x23c/0x3e0 [mlx5_ib]
   mlx5_ib_invalidate_range+0x2e1/0x330 [mlx5_ib]
   __mmu_notifier_invalidate_range_start+0x1e1/0x240
   zap_page_range_single+0xf1/0x1a0
   madvise_vma_behavior+0x677/0x6e0
   do_madvise+0x1a2/0x4b0
   __x64_sys_madvise+0x25/0x30
   do_syscall_64+0x6b/0x140
   entry_SYSCALL_64_after_hwframe+0x76/0x7e

The Linux kernel CVE team has assigned CVE-2025-21732 to this issue.


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

	Issue introduced in 5.13 with commit e6fb246ccafbdfc86e0750af021628132fdbceac and fixed in 6.12.14 with commit b13d32786acabf70a7b04ed24b7468fc3c82977c
	Issue introduced in 5.13 with commit e6fb246ccafbdfc86e0750af021628132fdbceac and fixed in 6.13.3 with commit 5297f5ddffef47b94172ab0d3d62270002a3dcc1
	Issue introduced in 5.13 with commit e6fb246ccafbdfc86e0750af021628132fdbceac and fixed in 6.14-rc1 with commit abb604a1a9c87255c7a6f3b784410a9707baf467

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-2025-21732
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/mr.c
	drivers/infiniband/hw/mlx5/odp.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/b13d32786acabf70a7b04ed24b7468fc3c82977c
	https://git.kernel.org/stable/c/5297f5ddffef47b94172ab0d3d62270002a3dcc1
	https://git.kernel.org/stable/c/abb604a1a9c87255c7a6f3b784410a9707baf467