CVE-2026-80720: iomap: add a separate bio_set for iomap_split_ioend

CVE-2026-80720: iomap: add a separate bio_set for iomap_split_ioend

[Greg Kroah-Hartman]

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

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

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

iomap: add a separate bio_set for iomap_split_ioend

iomap_split_ioend can split bios that already come from
iomap_ioend_bioset and thus deadlock when the bioset is exhausted.

Add a separate bio_set to avoid this deadlock.

Christian Brauner <brauner@kernel.org> says:
Mark iomap_ioend_split_bioset static as it is only used in ioend.c,
fixing the sparse warning reported by the kernel test robot.

The Linux kernel CVE team has assigned CVE-2026-80720 to this issue.


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

	Issue introduced in 6.15 with commit 5fcbd555d48390a8c819ba7fdf55fbfcabe05c80 and fixed in 6.18.44 with commit cfc686a1174aa904dcad9b9a7c5e46b484d27e4e
	Issue introduced in 6.15 with commit 5fcbd555d48390a8c819ba7fdf55fbfcabe05c80 and fixed in 7.1.8 with commit 4a869be56e9f6ce7462abcf324ebdefc5de051be
	Issue introduced in 6.15 with commit 5fcbd555d48390a8c819ba7fdf55fbfcabe05c80 and fixed in 7.2 with commit c679ce3be6cb63763d68ab9b5d9d73ddc0a40762

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-2026-80720
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/iomap/ioend.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/cfc686a1174aa904dcad9b9a7c5e46b484d27e4e
	https://git.kernel.org/stable/c/4a869be56e9f6ce7462abcf324ebdefc5de051be
	https://git.kernel.org/stable/c/c679ce3be6cb63763d68ab9b5d9d73ddc0a40762