Commit 19a1c409 authored by Al Viro's avatar Al Viro

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: 56cbb429 ("switch the remnants of releasing the mountpoint away from fs_pin")
Reported-by: default avatarNikolay Borisov <nborisov@suse.com>
Tested-by: default avatarNikolay Borisov <nborisov@suse.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 18253e03
...@@ -1463,7 +1463,6 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how) ...@@ -1463,7 +1463,6 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
p->mnt.mnt_flags |= MNT_SYNC_UMOUNT; p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
disconnect = disconnect_mount(p, how); disconnect = disconnect_mount(p, how);
if (mnt_has_parent(p)) { if (mnt_has_parent(p)) {
mnt_add_count(p->mnt_parent, -1); mnt_add_count(p->mnt_parent, -1);
if (!disconnect) { if (!disconnect) {
...@@ -1471,10 +1470,11 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how) ...@@ -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); list_add_tail(&p->mnt_child, &p->mnt_parent->mnt_mounts);
} else { } else {
umount_mnt(p); umount_mnt(p);
hlist_add_head(&p->mnt_umount, &unmounted);
} }
} }
change_mnt_propagation(p, MS_PRIVATE); change_mnt_propagation(p, MS_PRIVATE);
if (disconnect)
hlist_add_head(&p->mnt_umount, &unmounted);
} }
} }
......
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