linux-cve-announce - CVE-2025-68375: perf/x86: Fix NULL event access and potential PEBS record loss

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: <2025122402-CVE-2025-68375-aa1b@gregkh>
Date: Wed, 24 Dec 2025 11:35:20 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68375: perf/x86: Fix NULL event access and potential PEBS record loss

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

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

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

perf/x86: Fix NULL event access and potential PEBS record loss

When intel_pmu_drain_pebs_icl() is called to drain PEBS records, the
perf_event_overflow() could be called to process the last PEBS record.

While perf_event_overflow() could trigger the interrupt throttle and
stop all events of the group, like what the below call-chain shows.

perf_event_overflow()
  -> __perf_event_overflow()
    ->__perf_event_account_interrupt()
      -> perf_event_throttle_group()
        -> perf_event_throttle()
          -> event->pmu->stop()
            -> x86_pmu_stop()

The side effect of stopping the events is that all corresponding event
pointers in cpuc->events[] array are cleared to NULL.

Assume there are two PEBS events (event a and event b) in a group. When
intel_pmu_drain_pebs_icl() calls perf_event_overflow() to process the
last PEBS record of PEBS event a, interrupt throttle is triggered and
all pointers of event a and event b are cleared to NULL. Then
intel_pmu_drain_pebs_icl() tries to process the last PEBS record of
event b and encounters NULL pointer access.

To avoid this issue, move cpuc->events[] clearing from x86_pmu_stop()
to x86_pmu_del(). It's safe since cpuc->active_mask or
cpuc->pebs_enabled is always checked before access the event pointer
from cpuc->events[].

The Linux kernel CVE team has assigned CVE-2025-68375 to this issue.

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

	Issue introduced in 6.16 with commit 9734e25fbf5ae68eb04234b2cd14a4b36ab89141 and fixed in 6.17.13 with commit cf69b99805c263117305ac6dffbc85aaf9259d32
	Issue introduced in 6.16 with commit 9734e25fbf5ae68eb04234b2cd14a4b36ab89141 and fixed in 6.18.2 with commit 6b089028bff1f2ff9e0c62b8f1faca1a620e5d6e
	Issue introduced in 6.16 with commit 9734e25fbf5ae68eb04234b2cd14a4b36ab89141 and fixed in 6.19-rc1 with commit 7e772a93eb61cb6265bdd1c5bde17d0f2718b452

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-2025-68375
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:
	arch/x86/events/core.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/cf69b99805c263117305ac6dffbc85aaf9259d32
	https://git.kernel.org/stable/c/6b089028bff1f2ff9e0c62b8f1faca1a620e5d6e
	https://git.kernel.org/stable/c/7e772a93eb61cb6265bdd1c5bde17d0f2718b452