Proxmox-Port/linux-loongson
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson synced 2025-08-28 18:10:32 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Don't propagate mounts into detached trees

Browse Source 
All versions up to 6.14 did not propagate mount events into detached
tree.  Shortly after 6.14 a merge of vfs-6.15-rc1.mount.namespace
(130e696aa6) has changed that.

Unfortunately, that has caused userland regressions (reported in
https://lore.kernel.org/all/CAOYeF9WQhFDe+BGW=Dp5fK8oRy5AgZ6zokVyTj1Wp4EUiYgt4w@mail.gmail.com/)

Straight revert wouldn't be an option - in particular, the variant in 6.14
had a bug that got fixed in d1ddc6f1d9 ("fix IS_MNT_PROPAGATING uses")
and we don't want to bring the bug back.

This is a modification of manual revert posted by Christian, with changes
needed to avoid reintroducing the breakage in scenario described in
d1ddc6f1d9.

Cc: stable@vger.kernel.org
Reported-by: Allison Karlitskaya <lis@redhat.com>
Tested-by: Allison Karlitskaya <lis@redhat.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Co-developed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2025-05-23 19:20:36 -04:00
parent d1ddc6f1d9
commit 3b5260d12b
3 changed files with 4 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
fs/mount.h
View File

@ -7,10 +7,6 @@
extern struct list_head notify_list; extern struct list_head notify_list;
typedef __u32 __bitwise mntns_flags_t;
#define MNTNS_PROPAGATING ((__force mntns_flags_t)(1 << 0))
struct mnt_namespace { struct mnt_namespace {
struct ns_common ns; struct ns_common ns;
struct mount * root; struct mount * root;
@ -37,7 +33,6 @@ struct mnt_namespace {
struct rb_node mnt_ns_tree_node; /* node in the mnt_ns_tree */ struct rb_node mnt_ns_tree_node; /* node in the mnt_ns_tree */
struct list_head mnt_ns_list; /* entry in the sequential list of mounts namespace */ struct list_head mnt_ns_list; /* entry in the sequential list of mounts namespace */
refcount_t passive; /* number references not pinning @mounts */ refcount_t passive; /* number references not pinning @mounts */
mntns_flags_t mntns_flags;
} __randomize_layout; } __randomize_layout;
struct mnt_pcp { struct mnt_pcp {

13
fs/namespace.c
View File

@ -3648,7 +3648,7 @@ static int do_move_mount(struct path *old_path,
if (!(attached ? check_mnt(old) : is_anon_ns(ns))) if (!(attached ? check_mnt(old) : is_anon_ns(ns)))
goto out; goto out;
if (is_anon_ns(ns)) { if (is_anon_ns(ns) && ns == p->mnt_ns) {
/* /*
* Ending up with two files referring to the root of the * Ending up with two files referring to the root of the
* same anonymous mount namespace would cause an error * same anonymous mount namespace would cause an error
@ -3656,16 +3656,7 @@ static int do_move_mount(struct path *old_path,
* twice into the mount tree which would be rejected * twice into the mount tree which would be rejected
* later. But be explicit about it right here. * later. But be explicit about it right here.
*/ */
if ((is_anon_ns(p->mnt_ns) && ns == p->mnt_ns))
goto out; goto out;
/*
* If this is an anonymous mount tree ensure that mount
* propagation can detect mounts that were just
* propagated to the target mount tree so we don't
* propagate onto them.
*/
ns->mntns_flags |= MNTNS_PROPAGATING;
} else if (is_anon_ns(p->mnt_ns)) { } else if (is_anon_ns(p->mnt_ns)) {
/* /*
* Don't allow moving an attached mount tree to an * Don't allow moving an attached mount tree to an
@ -3722,8 +3713,6 @@ static int do_move_mount(struct path *old_path,
if (attached) if (attached)
put_mountpoint(old_mp); put_mountpoint(old_mp);
out: out:
if (is_anon_ns(ns))
ns->mntns_flags &= ~MNTNS_PROPAGATING;
unlock_mount(mp); unlock_mount(mp);
if (!err) { if (!err) {
if (attached) { if (attached) {

4
fs/pnode.c
View File

@ -231,8 +231,8 @@ static int propagate_one(struct mount *m, struct mountpoint *dest_mp)
/* skip if mountpoint isn't visible in m */ /* skip if mountpoint isn't visible in m */
if (!is_subdir(dest_mp->m_dentry, m->mnt.mnt_root)) if (!is_subdir(dest_mp->m_dentry, m->mnt.mnt_root))
return 0; return 0;
/* skip if m is in the anon_ns we are emptying */ /* skip if m is in the anon_ns */
if (m->mnt_ns->mntns_flags & MNTNS_PROPAGATING) if (is_anon_ns(m->mnt_ns))
return 0; return 0;
if (peers(m, last_dest)) { if (peers(m, last_dest)) {