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Message-ID: <2025100427-CVE-2023-53591-8496@gregkh>
Date: Sat, 4 Oct 2025 17:51:45 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53591: net/mlx5e: Fix deadlock in tc route query code
From: Greg Kroah-Hartman <gregkh@...nel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Fix deadlock in tc route query code
Cited commit causes ABBA deadlock[0] when peer flows are created while
holding the devcom rw semaphore. Due to peer flows offload implementation
the lock is taken much higher up the call chain and there is no obvious way
to easily fix the deadlock. Instead, since tc route query code needs the
peer eswitch structure only to perform a lookup in xarray and doesn't
perform any sleeping operations with it, refactor the code for lockless
execution in following ways:
- RCUify the devcom 'data' pointer. When resetting the pointer
synchronously wait for RCU grace period before returning. This is fine
since devcom is currently only used for synchronization of
pairing/unpairing of eswitches which is rare and already expensive as-is.
- Wrap all usages of 'paired' boolean in {READ|WRITE}_ONCE(). The flag has
already been used in some unlocked contexts without proper
annotations (e.g. users of mlx5_devcom_is_paired() function), but it wasn't
an issue since all relevant code paths checked it again after obtaining the
devcom semaphore. Now it is also used by mlx5_devcom_get_peer_data_rcu() as
"best effort" check to return NULL when devcom is being unpaired. Note that
while RCU read lock doesn't prevent the unpaired flag from being changed
concurrently it still guarantees that reader can continue to use 'data'.
- Refactor mlx5e_tc_query_route_vport() function to use new
mlx5_devcom_get_peer_data_rcu() API which fixes the deadlock.
[0]:
[ 164.599612] ======================================================
[ 164.600142] WARNING: possible circular locking dependency detected
[ 164.600667] 6.3.0-rc3+ #1 Not tainted
[ 164.601021] ------------------------------------------------------
[ 164.601557] handler1/3456 is trying to acquire lock:
[ 164.601998] ffff88811f1714b0 (&esw->offloads.encap_tbl_lock){+.+.}-{3:3}, at: mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core]
[ 164.603078]
but task is already holding lock:
[ 164.603617] ffff88810137fc98 (&comp->sem){++++}-{3:3}, at: mlx5_devcom_get_peer_data+0x37/0x80 [mlx5_core]
[ 164.604459]
which lock already depends on the new lock.
[ 164.605190]
the existing dependency chain (in reverse order) is:
[ 164.605848]
-> #1 (&comp->sem){++++}-{3:3}:
[ 164.606380] down_read+0x39/0x50
[ 164.606772] mlx5_devcom_get_peer_data+0x37/0x80 [mlx5_core]
[ 164.607336] mlx5e_tc_query_route_vport+0x86/0xc0 [mlx5_core]
[ 164.607914] mlx5e_tc_tun_route_lookup+0x1a4/0x1d0 [mlx5_core]
[ 164.608495] mlx5e_attach_decap_route+0xc6/0x1e0 [mlx5_core]
[ 164.609063] mlx5e_tc_add_fdb_flow+0x1ea/0x360 [mlx5_core]
[ 164.609627] __mlx5e_add_fdb_flow+0x2d2/0x430 [mlx5_core]
[ 164.610175] mlx5e_configure_flower+0x952/0x1a20 [mlx5_core]
[ 164.610741] tc_setup_cb_add+0xd4/0x200
[ 164.611146] fl_hw_replace_filter+0x14c/0x1f0 [cls_flower]
[ 164.611661] fl_change+0xc95/0x18a0 [cls_flower]
[ 164.612116] tc_new_tfilter+0x3fc/0xd20
[ 164.612516] rtnetlink_rcv_msg+0x418/0x5b0
[ 164.612936] netlink_rcv_skb+0x54/0x100
[ 164.613339] netlink_unicast+0x190/0x250
[ 164.613746] netlink_sendmsg+0x245/0x4a0
[ 164.614150] sock_sendmsg+0x38/0x60
[ 164.614522] ____sys_sendmsg+0x1d0/0x1e0
[ 164.614934] ___sys_sendmsg+0x80/0xc0
[ 164.615320] __sys_sendmsg+0x51/0x90
[ 164.615701] do_syscall_64+0x3d/0x90
[ 164.616083] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 164.616568]
-> #0 (&esw->offloads.encap_tbl_lock){+.+.}-{3:3}:
[ 164.617210] __lock_acquire+0x159e/0x26e0
[ 164.617638] lock_acquire+0xc2/0x2a0
[ 164.618018] __mutex_lock+0x92/0xcd0
[ 164.618401] mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core]
[ 164.618943] post_process_attr+0x153/0x2d0 [mlx5_core]
[ 164.619471] mlx5e_tc_add_fdb_flow+0x164/0x360 [mlx5_core]
[ 164.620021] __mlx5e_add_fdb_flow+0x2d2/0x430 [mlx5_core]
[ 164.620564] mlx5e_configure_flower+0xe33/0x1a20 [mlx5_core]
[ 164.621125] tc_setup_cb_add+0xd4/0x200
[ 164.621531] fl_hw_replace_filter+0x14c/0x1f0 [cls_flower]
[ 164.622047] fl_change+0xc95/0x18a0 [cls_flower]
[ 164.622500] tc_new_tfilter+0x3fc/0xd20
[ 164.622906] rtnetlink_rcv_msg+0x418/0x5b0
[ 164.623324] netlink_rcv_skb+0x54/0x100
[ 164.623727] netlink_unicast+0x190/0x250
[ 164.624138] netlink_sendmsg+0x245/0x4a0
[ 164.624544] sock_sendmsg+0x38/0x60
[ 164.624919] ____sys_sendmsg+0x1d0/0x1e0
[ 164.625340] ___sys_sendmsg+0x80/0xc0
[ 164.625731] __sys_sendmsg+0x51/0x90
[ 164.626117] do_syscall_64+0x3d/0x90
[ 164.626502] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 164.626995]
other info that might help us debug this:
[ 164.627725] Possible unsafe locking scenario:
[ 164.628268] CPU0 CPU1
[ 164.628683] ---- ----
[ 164.629098] lock(&comp->sem);
[ 164.629421] lock(&esw->offloads.encap_tbl_lock);
[ 164.630066] lock(&comp->sem);
[ 164.630555] lock(&esw->offloads.encap_tbl_lock);
[ 164.630993]
*** DEADLOCK ***
[ 164.631575] 3 locks held by handler1/3456:
[ 164.631962] #0: ffff888124b75130 (&block->cb_lock){++++}-{3:3}, at: tc_setup_cb_add+0x5b/0x200
[ 164.632703] #1: ffff888116e512b8 (&esw->mode_lock){++++}-{3:3}, at: mlx5_esw_hold+0x39/0x50 [mlx5_core]
[ 164.633552] #2: ffff88810137fc98 (&comp->sem){++++}-{3:3}, at: mlx5_devcom_get_peer_data+0x37/0x80 [mlx5_core]
[ 164.634435]
stack backtrace:
[ 164.634883] CPU: 17 PID: 3456 Comm: handler1 Not tainted 6.3.0-rc3+ #1
[ 164.635431] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 164.636340] Call Trace:
[ 164.636616] <TASK>
[ 164.636863] dump_stack_lvl+0x47/0x70
[ 164.637217] check_noncircular+0xfe/0x110
[ 164.637601] __lock_acquire+0x159e/0x26e0
[ 164.637977] ? mlx5_cmd_set_fte+0x5b0/0x830 [mlx5_core]
[ 164.638472] lock_acquire+0xc2/0x2a0
[ 164.638828] ? mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core]
[ 164.639339] ? lock_is_held_type+0x98/0x110
[ 164.639728] __mutex_lock+0x92/0xcd0
[ 164.640074] ? mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core]
[ 164.640576] ? __lock_acquire+0x382/0x26e0
[ 164.640958] ? mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core]
[ 164.641468] ? mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core]
[ 164.641965] mlx5e_attach_encap+0xd8/0x8b0 [mlx5_core]
[ 164.642454] ? lock_release+0xbf/0x240
[ 164.642819] post_process_attr+0x153/0x2d0 [mlx5_core]
[ 164.643318] mlx5e_tc_add_fdb_flow+0x164/0x360 [mlx5_core]
[ 164.643835] __mlx5e_add_fdb_flow+0x2d2/0x430 [mlx5_core]
[ 164.644340] mlx5e_configure_flower+0xe33/0x1a20 [mlx5_core]
[ 164.644862] ? lock_acquire+0xc2/0x2a0
[ 164.645219] tc_setup_cb_add+0xd4/0x200
[ 164.645588] fl_hw_replace_filter+0x14c/0x1f0 [cls_flower]
[ 164.646067] fl_change+0xc95/0x18a0 [cls_flower]
[ 164.646488] tc_new_tfilter+0x3fc/0xd20
[ 164.646861] ? tc_del_tfilter+0x810/0x810
[ 164.647236] rtnetlink_rcv_msg+0x418/0x5b0
[ 164.647621] ? rtnl_setlink+0x160/0x160
[ 164.647982] netlink_rcv_skb+0x54/0x100
[ 164.648348] netlink_unicast+0x190/0x250
[ 164.648722] netlink_sendmsg+0x245/0x4a0
[ 164.649090] sock_sendmsg+0x38/0x60
[ 164.649434] ____sys_sendmsg+0x1d0/0x1e0
[ 164.649804] ? copy_msghdr_from_user+0x6d/0xa0
[ 164.650213] ___sys_sendmsg+0x80/0xc0
[ 164.650563] ? lock_acquire+0xc2/0x2a0
[ 164.650926] ? lock_acquire+0xc2/0x2a0
[ 164.651286] ? __fget_files+0x5/0x190
[ 164.651644] ? find_held_lock+0x2b/0x80
[ 164.652006] ? __fget_files+0xb9/0x190
[ 164.652365] ? lock_release+0xbf/0x240
[ 164.652723] ? __fget_files+0xd3/0x190
[ 164.653079] __sys_sendmsg+0x51/0x90
[ 164.653435] do_syscall_64+0x3d/0x90
[ 164.653784] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 164.654229] RIP: 0033:0x7f378054f8bd
[ 164.654577] Code: 28 89 54 24 1c 48 89 74 24 10 89 7c 24 08 e8 6a c3 f4 ff 8b 54 24 1c 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 33 44 89 c7 48 89 44 24 08 e8 be c3 f4 ff 48
[ 164.656041] RSP: 002b:00007f377fa114b0 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
[ 164.656701] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f378054f8bd
[ 164.657297] RDX: 0000000000000000 RSI: 00007f377fa11540 RDI: 0000000000000014
[ 164.657885] RBP: 00007f377fa12278 R08: 0000000000000000 R09: 000000000000015c
[ 164.658472] R10: 00007f377fa123d0 R11: 0000000000000293 R12: 0000560962d99bd0
[ 164.665317] R13: 0000000000000000 R14: 0000560962d99bd0 R15: 00007f377fa11540
The Linux kernel CVE team has assigned CVE-2023-53591 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.15 with commit f9d196bd632b8b79261ec3366c30ec3923ea9a02 and fixed in 5.15.115 with commit 69966bce28da6aadccfd968b75d128a79da32d17
Issue introduced in 5.15 with commit f9d196bd632b8b79261ec3366c30ec3923ea9a02 and fixed in 6.1.31 with commit 362063df6ceec80b0b6798b61ae03504dcc125a5
Issue introduced in 5.15 with commit f9d196bd632b8b79261ec3366c30ec3923ea9a02 and fixed in 6.3.5 with commit a7236e420a7d8082b1df4b3e05c739dd2642a662
Issue introduced in 5.15 with commit f9d196bd632b8b79261ec3366c30ec3923ea9a02 and fixed in 6.4 with commit 691c041bf20899fc13c793f92ba61ab660fa3a30
Issue introduced in 5.13.17 with commit 87a0625cf1c76caeaa15c576a0b2fcad4b9387d0
Issue introduced in 5.14.4 with commit 7778fe1a6a6c069a460e4e3ff8ed3722392a4b5b
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-2023-53591
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/mellanox/mlx5/core/en_tc.c
drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c
drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.h
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/69966bce28da6aadccfd968b75d128a79da32d17
https://git.kernel.org/stable/c/362063df6ceec80b0b6798b61ae03504dcc125a5
https://git.kernel.org/stable/c/a7236e420a7d8082b1df4b3e05c739dd2642a662
https://git.kernel.org/stable/c/691c041bf20899fc13c793f92ba61ab660fa3a30
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