From: Yuto Ohnuki <ytohnuki@amazon.com> stable inclusion from stable-v5.10.252 commit e6cc490048f78b009259a5f032acead9f789c34c category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14197 CVE: CVE-2026-31455 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=t... -------------------------------- [ Upstream commit 4f24a767e3d64a5f58c595b5c29b6063a201f1e3 ] The unmount sequence in xfs_unmount_flush_inodes() pushed the AIL while background reclaim and inodegc are still running. This is broken independently of any use-after-free issues - background reclaim and inodegc should not be running while the AIL is being pushed during unmount, as inodegc can dirty and insert inodes into the AIL during the flush, and background reclaim can race to abort and free dirty inodes. Reorder xfs_unmount_flush_inodes() to stop inodegc and cancel background reclaim before pushing the AIL. Stop inodegc before cancelling m_reclaim_work because the inodegc worker can re-queue m_reclaim_work via xfs_inodegc_set_reclaimable. Reported-by: syzbot+652af2b3c5569c4ab63c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=652af2b3c5569c4ab63c Fixes: 90c60e164012 ("xfs: xfs_iflush() is no longer necessary") Cc: stable@vger.kernel.org # v5.9 Signed-off-by: Yuto Ohnuki <ytohnuki@amazon.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org> [ dropped xfs_inodegc_stop() call ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: fs/xfs/xfs_mount.c [Context conflicts] Signed-off-by: Long Li <leo.lilong@huawei.com> --- fs/xfs/xfs_mount.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 4983fe7eadf0..cb99ac78d904 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -687,8 +687,9 @@ xfs_ifree_unmount( * have been retrying in the background. This will prevent never-ending * retries in AIL pushing from hanging the unmount. * - * Finally, we can push the AIL to clean all the remaining dirty objects, then - * reclaim the remaining inodes that are still in memory at this point in time. + * Stop inodegc and background reclaim before pushing the AIL so that they + * are not running while the AIL is being flushed. Then push the AIL to + * clean all the remaining dirty objects and reclaim the remaining inodes. */ static void xfs_unmount_flush_inodes( @@ -700,9 +701,9 @@ xfs_unmount_flush_inodes( set_bit(XFS_OPSTATE_UNMOUNTING, &mp->m_opstate); - xfs_ail_push_all_sync(mp->m_ail); xfs_inodegc_stop(mp); cancel_delayed_work_sync(&mp->m_reclaim_work); + xfs_ail_push_all_sync(mp->m_ail); xfs_reclaim_inodes(mp); xfs_health_unmount(mp); } -- 2.52.0