CVE-2026-97933: tracing: Take trace_array reference when opening a tracer options file

CVE-2026-97933: tracing: Take trace_array reference when opening a tracer options file

[Greg Kroah-Hartman]

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

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

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

tracing: Take trace_array reference when opening a tracer options file

When a tracer option file is opened, it is passed a descriptor that points
to an element on the trace_array's topts array. This element has
information to find the trace array and other information. It uses this
element to take a reference of the trace_array so that the trace_array
does not get removed while this file is opened.

Unfortunately, there's a race condition where the element itself could be
freed by the removal of the instance the trace_array represents causing a
use-after-free as this element that is used to find the trace_array to
increment its reference counter is also freed when the instance is
removed.

To solve this, add a trace_array_tracer_options_get() helper function that
will take the address of the element that is passed to the open function
by the inode->i_private pointer and search all the trace_arrays under a
lock to find the one that the element's address is in the range of the
trace_arrays topts array elements. When a match happens, that trace_array's
reference would be increased.

Note, there's a race where if an admin was deleting and creating trace
instances at the same time and the memory of the old trace_array's array
matched the memory of the new trace_array that it could in theory open the
option from the wrong trace array. But we do not care because it would be
stupid to perform that kind of action. As long as the only thing that can
happen is that the option from the wrong trace array is used and doesn't
crash the kernel it will only make the user confused. But if they are
doing something stupid like this, they are already confused, so no harm
done.

The Linux kernel CVE team has assigned CVE-2026-97933 to this issue.


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

	Issue introduced in 6.6 with commit 7e2cfbd2d3c86afcd5c26b5c4b1dd251f63c5838 and fixed in 7.2.7 with commit b2fb87d29ffb3a7a9ccc5acf12898ecb80587427
	Issue introduced in 6.6 with commit 7e2cfbd2d3c86afcd5c26b5c4b1dd251f63c5838 and fixed in 7.3-rc3 with commit ed0aff60f83a9bdc2f6556376ac79c96b3ce7e80
	Issue introduced in 5.4.257 with commit 952e477f908048145a5eb2ed3d431d9efc1e1073
	Issue introduced in 5.10.197 with commit b3183f5f05cd867f5c17122773ca5aa8d07b51af
	Issue introduced in 5.15.133 with commit bf38c1d29f8bfe9631b62a67f8dd1b8f7efb7139
	Issue introduced in 6.1.55 with commit 2617afde0c3db285778734b0ccad9a55b4f9cda2
	Issue introduced in 6.5.5 with commit 586787a0331aa2d7d244e9c4400d2a73295b0cf0

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-2026-97933
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.c
	kernel/trace/trace.h


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/b2fb87d29ffb3a7a9ccc5acf12898ecb80587427
	https://git.kernel.org/stable/c/ed0aff60f83a9bdc2f6556376ac79c96b3ce7e80