linux-cve-announce - CVE-2025-38311: iavf: get rid of the crit lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025071015-CVE-2025-38311-2a53@gregkh>
Date: Thu, 10 Jul 2025 09:42:52 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38311: iavf: get rid of the crit lock

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

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

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

iavf: get rid of the crit lock

Get rid of the crit lock.
That frees us from the error prone logic of try_locks.

Thanks to netdev_lock() by Jakub it is now easy, and in most cases we were
protected by it already - replace crit lock by netdev lock when it was not
the case.

Lockdep reports that we should cancel the work under crit_lock [splat1],
and that was the scheme we have mostly followed since [1] by Slawomir.
But when that is done we still got into deadlocks [splat2]. So instead
we should look at the bigger problem, namely "weird locking/scheduling"
of the iavf. The first step to fix that is to remove the crit lock.
I will followup with a -next series that simplifies scheduling/tasks.

Cancel the work without netdev lock (weird unlock+lock scheme),
to fix the [splat2] (which would be totally ugly if we would kept
the crit lock).

Extend protected part of iavf_watchdog_task() to include scheduling
more work.

Note that the removed comment in iavf_reset_task() was misplaced,
it belonged to inside of the removed if condition, so it's gone now.

[splat1] - w/o this patch - The deadlock during VF removal:
     WARNING: possible circular locking dependency detected
     sh/3825 is trying to acquire lock:
      ((work_completion)(&(&adapter->watchdog_task)->work)){+.+.}-{0:0}, at: start_flush_work+0x1a1/0x470
          but task is already holding lock:
      (&adapter->crit_lock){+.+.}-{4:4}, at: iavf_remove+0xd1/0x690 [iavf]
          which lock already depends on the new lock.

[splat2] - when cancelling work under crit lock, w/o this series,
	   see [2] for the band aid attempt
    WARNING: possible circular locking dependency detected
    sh/3550 is trying to acquire lock:
    ((wq_completion)iavf){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90
        but task is already holding lock:
    (&dev->lock){+.+.}-{4:4}, at: iavf_remove+0xa6/0x6e0 [iavf]
        which lock already depends on the new lock.

[1] fc2e6b3b132a ("iavf: Rework mutexes for better synchronisation")
[2] https://github.com/pkitszel/linux/commit/52dddbfc2bb60294083f5711a158a

The Linux kernel CVE team has assigned CVE-2025-38311 to this issue.


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

	Issue introduced in 6.5 with commit d1639a17319ba78a018280cd2df6577a7e5d9fab and fixed in 6.15.3 with commit 620ab4d6215de0b25227f9fff1a8c7fb66837cb8
	Issue introduced in 6.5 with commit d1639a17319ba78a018280cd2df6577a7e5d9fab and fixed in 6.16-rc1 with commit 120f28a6f314fef7f282c99f196923fe44081cad
	Issue introduced in 6.1.42 with commit 2647ff59c52ef42c853c905817ed1a7f092d59a5
	Issue introduced in 6.4.7 with commit 63d14a43128540016ebd4f7fa3ad3a2f0d6e642c

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-2025-38311
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/intel/iavf/iavf.h
	drivers/net/ethernet/intel/iavf/iavf_ethtool.c
	drivers/net/ethernet/intel/iavf/iavf_main.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/620ab4d6215de0b25227f9fff1a8c7fb66837cb8
	https://git.kernel.org/stable/c/120f28a6f314fef7f282c99f196923fe44081cad