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In the Linux kernel, the following vulnerability has been...

Moderate severity Unreviewed Published May 1, 2024 to the GitHub Advisory Database • Updated Jun 3, 2024

Package

No package listedSuggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

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

net/mlx5e: Prevent deadlock while disabling aRFS

When disabling aRFS under the priv->state_lock, any scheduled
aRFS works are canceled using the cancel_work_sync function,
which waits for the work to end if it has already started.
However, while waiting for the work handler, the handler will
try to acquire the state_lock which is already acquired.

The worker acquires the lock to delete the rules if the state
is down, which is not the worker's responsibility since
disabling aRFS deletes the rules.

Add an aRFS state variable, which indicates whether the aRFS is
enabled and prevent adding rules when the aRFS is disabled.

Kernel log:

======================================================
WARNING: possible circular locking dependency detected
6.7.0-rc4_net_next_mlx5_5483eb2 #1 Tainted: G I

ethtool/386089 is trying to acquire lock:
ffff88810f21ce68 ((work_completion)(&rule->arfs_work)){+.+.}-{0:0}, at: __flush_work+0x74/0x4e0

but task is already holding lock:
ffff8884a1808cc0 (&priv->state_lock){+.+.}-{3:3}, at: mlx5e_ethtool_set_channels+0x53/0x200 [mlx5_core]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&priv->state_lock){+.+.}-{3:3}:
__mutex_lock+0x80/0xc90
arfs_handle_work+0x4b/0x3b0 [mlx5_core]
process_one_work+0x1dc/0x4a0
worker_thread+0x1bf/0x3c0
kthread+0xd7/0x100
ret_from_fork+0x2d/0x50
ret_from_fork_asm+0x11/0x20

-> #0 ((work_completion)(&rule->arfs_work)){+.+.}-{0:0}:
__lock_acquire+0x17b4/0x2c80
lock_acquire+0xd0/0x2b0
__flush_work+0x7a/0x4e0
__cancel_work_timer+0x131/0x1c0
arfs_del_rules+0x143/0x1e0 [mlx5_core]
mlx5e_arfs_disable+0x1b/0x30 [mlx5_core]
mlx5e_ethtool_set_channels+0xcb/0x200 [mlx5_core]
ethnl_set_channels+0x28f/0x3b0
ethnl_default_set_doit+0xec/0x240
genl_family_rcv_msg_doit+0xd0/0x120
genl_rcv_msg+0x188/0x2c0
netlink_rcv_skb+0x54/0x100
genl_rcv+0x24/0x40
netlink_unicast+0x1a1/0x270
netlink_sendmsg+0x214/0x460
__sock_sendmsg+0x38/0x60
__sys_sendto+0x113/0x170
__x64_sys_sendto+0x20/0x30
do_syscall_64+0x40/0xe0
entry_SYSCALL_64_after_hwframe+0x46/0x4e

other info that might help us debug this:

Possible unsafe locking scenario:

   CPU0                    CPU1
   ----                    ----

lock(&priv->state_lock);
lock((work_completion)(&rule->arfs_work));
lock(&priv->state_lock);
lock((work_completion)(&rule->arfs_work));

*** DEADLOCK ***

3 locks held by ethtool/386089:
#0: ffffffff82ea7210 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40
#1: ffffffff82e94c88 (rtnl_mutex){+.+.}-{3:3}, at: ethnl_default_set_doit+0xd3/0x240
#2: ffff8884a1808cc0 (&priv->state_lock){+.+.}-{3:3}, at: mlx5e_ethtool_set_channels+0x53/0x200 [mlx5_core]

stack backtrace:
CPU: 15 PID: 386089 Comm: ethtool Tainted: G I 6.7.0-rc4_net_next_mlx5_5483eb2 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Call Trace:

dump_stack_lvl+0x60/0xa0
check_noncircular+0x144/0x160
__lock_acquire+0x17b4/0x2c80
lock_acquire+0xd0/0x2b0
? __flush_work+0x74/0x4e0
? save_trace+0x3e/0x360
? __flush_work+0x74/0x4e0
__flush_work+0x7a/0x4e0
? __flush_work+0x74/0x4e0
? __lock_acquire+0xa78/0x2c80
? lock_acquire+0xd0/0x2b0
? mark_held_locks+0x49/0x70
__cancel_work_timer+0x131/0x1c0
? mark_held_locks+0x49/0x70
arfs_del_rules+0x143/0x1e0 [mlx5_core]
mlx5e_arfs_disable+0x1b/0x30 [mlx5_core]
mlx5e_ethtool_set_channels+0xcb/0x200 [mlx5_core]
ethnl_set_channels+0x28f/0x3b0
ethnl_default_set_doit+0xec/0x240
genl_family_rcv_msg_doit+0xd0/0x120
genl_rcv_msg+0x188/0x2c0
? ethn
---truncated---

References

Published by the National Vulnerability Database May 1, 2024
Published to the GitHub Advisory Database May 1, 2024
Last updated Jun 3, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.042%
(5th percentile)

Weaknesses

CVE ID

CVE-2024-27014

GHSA ID

GHSA-gj8m-4ccw-v82h

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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