CVE-2026-68177: tracing: Delay module ref count for "enable_event" trigger

CVE-2026-68177: tracing: Delay module ref count for "enable_event" trigger

[Greg Kroah-Hartman]

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

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

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

tracing: Delay module ref count for "enable_event" trigger

Triggers are now delayed from freeing, but can still be triggered until
after the RCU grace period has ended. The freeing of the enable_event data
is put into the private_data_free() callback, but the put of the module
refcount is done immediately.

It is possible that if a module is removed that has an event that would
enable (or disable) it is still active, it can read the data of the module
after it is removed causing a use-after-free bug.

Move the trace_event_put_ref() that releases the module into the delayed
callback so that the module can not be removed until any reference to its
events are finished.

The Linux kernel CVE team has assigned CVE-2026-68177 to this issue.


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

	Issue introduced in 6.19 with commit 61d445af0a7c70018111919e47beaaee15653f2f and fixed in 7.1.6 with commit 159fdc3e01dca5fdbc412fcd8b239895733a270d
	Issue introduced in 6.19 with commit 61d445af0a7c70018111919e47beaaee15653f2f and fixed in 7.2-rc5 with commit e091351b38818ef620d27f44f4bfd625f13afbff

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-2026-68177
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/trace_events_trigger.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/159fdc3e01dca5fdbc412fcd8b239895733a270d
	https://git.kernel.org/stable/c/e091351b38818ef620d27f44f4bfd625f13afbff