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authorAl Viro <viro@zeniv.linux.org.uk>2019-07-24 12:45:46 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2019-07-26 07:59:06 -0400
commit19a1c4092e7ca1ad1a72ac5535f902c483372cd5 (patch)
treed7bbba61680553364deec2a068fe0da41f1905cc
parent18253e034d2aeee140f82fc9fe89c4bce5c81799 (diff)
fix the struct mount leak in umount_tree()
We need to drop everything we remove from the tree, whether mnt_has_parent() is true or not. Usually the bug manifests as a slow memory leak (leaked struct mount for initramfs); it becomes much more visible in mount_subtree() users, such as btrfs. There we leak a struct mount for btrfs superblock being mounted, which prevents fs shutdown on subsequent umount. Fixes: 56cbb429d911 ("switch the remnants of releasing the mountpoint away from fs_pin") Reported-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/namespace.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 6464ea4acba9..d28d30b13043 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1463,7 +1463,6 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
disconnect = disconnect_mount(p, how);
-
if (mnt_has_parent(p)) {
mnt_add_count(p->mnt_parent, -1);
if (!disconnect) {
@@ -1471,10 +1470,11 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
list_add_tail(&p->mnt_child, &p->mnt_parent->mnt_mounts);
} else {
umount_mnt(p);
- hlist_add_head(&p->mnt_umount, &unmounted);
}
}
change_mnt_propagation(p, MS_PRIVATE);
+ if (disconnect)
+ hlist_add_head(&p->mnt_umount, &unmounted);
}
}

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