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| author |   Al Viro <viro@zeniv.linux.org.uk> | 2025-05-23 19:20:36 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2025-05-26 17:35:32 -0400 |
| commit | 3b5260d12b1fe76b566fe182de8abc586b827ed0 (patch) | |
| tree | 2a01faf26260c35ca94d34b8ba2f25e886dbe38e /fs/namespace.c | |
| parent | fix IS_MNT_PROPAGATING uses (diff) | |
| download | linux-rng-3b5260d12b1fe76b566fe182de8abc586b827ed0.tar.xz linux-rng-3b5260d12b1fe76b566fe182de8abc586b827ed0.zip | |
Don't propagate mounts into detached trees
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
(130e696aa68b) 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 d1ddc6f1d9f0 ("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
d1ddc6f1d9f0.
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>
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 15 |
1 files changed, 2 insertions, 13 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 1b466c54a357..623cd110076d 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3648,7 +3648,7 @@ static int do_move_mount(struct path *old_path, if (!(attached ? check_mnt(old) : is_anon_ns(ns))) 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 * 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 * later. But be explicit about it right here. */ - if ((is_anon_ns(p->mnt_ns) && ns == p->mnt_ns)) - 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; + goto out; } else if (is_anon_ns(p->mnt_ns)) { /* * 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) put_mountpoint(old_mp); out: - if (is_anon_ns(ns)) - ns->mntns_flags &= ~MNTNS_PROPAGATING; unlock_mount(mp); if (!err) { if (attached) { |