CVE-2026-64068: netfs: Fix missing locking around retry adding new subreqs

From: Greg Kroah-Hartman <[email protected]>

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

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

netfs: Fix missing locking around retry adding new subreqs

Fix netfs_retry_read_subrequests() and netfs_retry_write_stream() to take
the appropriate lock when adding extra subrequests into
stream->subrequests.

The Linux kernel CVE team has assigned CVE-2026-64068 to this issue.


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

	Issue introduced in 6.10 with commit 288ace2f57c9d06dd2e42bd80d03747d879a4068 and fixed in 7.0.11 with commit 393f3f0d7353a94b1e0bc4ca89c683fe983e5fd2
	Issue introduced in 6.10 with commit 288ace2f57c9d06dd2e42bd80d03747d879a4068 and fixed in 7.1 with commit cce18c263e9623872327ba3c956012f73c1179cc

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-2026-64068
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:
	fs/netfs/read_retry.c
	fs/netfs/write_retry.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/393f3f0d7353a94b1e0bc4ca89c683fe983e5fd2
	https://git.kernel.org/stable/c/cce18c263e9623872327ba3c956012f73c1179cc