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| author | Al Viro <viro@zeniv.linux.org.uk> | 2019-07-24 12:45:46 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2019-07-26 07:59:06 -0400 |
| commit | 19a1c4092e7ca1ad1a72ac5535f902c483372cd5 (patch) | |
| tree | d7bbba61680553364deec2a068fe0da41f1905cc | |
| parent | 18253e034d2aeee140f82fc9fe89c4bce5c81799 (diff) | |
| download | lwn-19a1c4092e7ca1ad1a72ac5535f902c483372cd5.tar.gz lwn-19a1c4092e7ca1ad1a72ac5535f902c483372cd5.zip | |
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.c | 4 |
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); } } |