linux-cve-announce - CVE-2025-39829: trace/fgraph: Fix the warning caused by missing unregister notifier

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Message-ID: <2025091617-CVE-2025-39829-2ef1@gregkh>
Date: Tue, 16 Sep 2025 15:00:35 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-39829: trace/fgraph: Fix the warning caused by missing unregister notifier

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

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

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

trace/fgraph: Fix the warning caused by missing unregister notifier

This warning was triggered during testing on v6.16:

notifier callback ftrace_suspend_notifier_call already registered
WARNING: CPU: 2 PID: 86 at kernel/notifier.c:23 notifier_chain_register+0x44/0xb0
...
Call Trace:
 <TASK>
 blocking_notifier_chain_register+0x34/0x60
 register_ftrace_graph+0x330/0x410
 ftrace_profile_write+0x1e9/0x340
 vfs_write+0xf8/0x420
 ? filp_flush+0x8a/0xa0
 ? filp_close+0x1f/0x30
 ? do_dup2+0xaf/0x160
 ksys_write+0x65/0xe0
 do_syscall_64+0xa4/0x260
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

When writing to the function_profile_enabled interface, the notifier was
not unregistered after start_graph_tracing failed, causing a warning the
next time function_profile_enabled was written.

Fixed by adding unregister_pm_notifier in the exception path.

The Linux kernel CVE team has assigned CVE-2025-39829 to this issue.

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

	Issue introduced in 2.6.30 with commit 4a2b8dda3f8705880ec7408135645602d5590f51 and fixed in 6.12.45 with commit 2a2deb9f8df70480050351ac27041f19bb9e718b
	Issue introduced in 2.6.30 with commit 4a2b8dda3f8705880ec7408135645602d5590f51 and fixed in 6.16.5 with commit 000aa47a51233fd38a629b029478e0278e1e9fbe
	Issue introduced in 2.6.30 with commit 4a2b8dda3f8705880ec7408135645602d5590f51 and fixed in 6.17-rc3 with commit edede7a6dcd7435395cf757d053974aaab6ab1c2

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-2025-39829
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:
	kernel/trace/fgraph.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/2a2deb9f8df70480050351ac27041f19bb9e718b
	https://git.kernel.org/stable/c/000aa47a51233fd38a629b029478e0278e1e9fbe
	https://git.kernel.org/stable/c/edede7a6dcd7435395cf757d053974aaab6ab1c2