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: 56cbb429d9
("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>
This commit is contained in:
parent
18253e034d
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19a1c4092e
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@ -1463,7 +1463,6 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
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p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
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disconnect = disconnect_mount(p, how);
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if (mnt_has_parent(p)) {
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mnt_add_count(p->mnt_parent, -1);
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if (!disconnect) {
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@ -1471,10 +1470,11 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
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list_add_tail(&p->mnt_child, &p->mnt_parent->mnt_mounts);
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} else {
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umount_mnt(p);
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hlist_add_head(&p->mnt_umount, &unmounted);
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}
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}
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change_mnt_propagation(p, MS_PRIVATE);
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if (disconnect)
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hlist_add_head(&p->mnt_umount, &unmounted);
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}
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}
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