CVE-2026-98081: btrfs: zoned: finish active block group cleanup if call_zone_finish() fails

CVE-2026-98081: btrfs: zoned: finish active block group cleanup if call_zone_finish() fails

[Greg Kroah-Hartman]

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

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

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

btrfs: zoned: finish active block group cleanup if call_zone_finish() fails

do_zone_finish() clears BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE before finishing
the zones. If call_zone_finish() then fails it returned early, leaving the
now inactive block group on fs_info->zone_active_bgs, leaking its
reference, the BTRFS_FS_NEED_ZONE_FINISH waiters are never woken, and as
its alloc_offset equals the zone capacity btrfs_zone_finish_one_bg() keeps
selecting it, spinning btrfs_zoned_activate_one_bg().

Fall through to the cleanup on failure too and return the error, but keep
the block group read-only as its zones are left inconsistent.

The Linux kernel CVE team has assigned CVE-2026-98081 to this issue.


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

	Issue introduced in 5.19 with commit d70cbdda75da3f258118a558c087157e073229fb and fixed in 6.12.111 with commit 36b9cdab44848f25879ca625275c92b007f84653
	Issue introduced in 5.19 with commit d70cbdda75da3f258118a558c087157e073229fb and fixed in 6.18.53 with commit 40370f02a1ca3760f8925ffcbe76eb4d91ea758d
	Issue introduced in 5.19 with commit d70cbdda75da3f258118a558c087157e073229fb and fixed in 7.2.7 with commit e1b168a53174b385e3548bfbd079513b22ac240c
	Issue introduced in 5.19 with commit d70cbdda75da3f258118a558c087157e073229fb and fixed in 7.3-rc2 with commit a18a6b93a2843b9d103d3456bbd4b3f90282a379

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-2026-98081
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/btrfs/zoned.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/36b9cdab44848f25879ca625275c92b007f84653
	https://git.kernel.org/stable/c/40370f02a1ca3760f8925ffcbe76eb4d91ea758d
	https://git.kernel.org/stable/c/e1b168a53174b385e3548bfbd079513b22ac240c
	https://git.kernel.org/stable/c/a18a6b93a2843b9d103d3456bbd4b3f90282a379