When cleaning up peer group ids in the failure path we need to make sure to hold on to the namespace lock. Otherwise another thread might just turn the mount from a shared into a non-shared mount concurrently.
Reported-by: syzbot+8ac3859139c685c4f597@syzkaller.appspotmail.com Link: https://lore.kernel.org/lkml/00000000000088694505f8132d77@google.com Fixes: 2a1867219c7b ("fs: add mount_setattr()") Cc: stable@vger.kernel.org # 5.12+ Signed-off-by: Christian Brauner brauner@kernel.org --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/namespace.c b/fs/namespace.c index bc0f15257b49..6836e937ee61 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -4183,9 +4183,9 @@ static int do_mount_setattr(struct path *path, struct mount_kattr *kattr) unlock_mount_hash();
if (kattr->propagation) { - namespace_unlock(); if (err) cleanup_group_ids(mnt, NULL); + namespace_unlock(); }
return err;
--- base-commit: 197b6b60ae7bc51dd0814953c562833143b292aa change-id: 20230330-vfs-mount_setattr-propagation-fix-363b7c59d7fb
On Thu, 30 Mar 2023 09:13:16 +0200, Christian Brauner wrote:
When cleaning up peer group ids in the failure path we need to make sure to hold on to the namespace lock. Otherwise another thread might just turn the mount from a shared into a non-shared mount concurrently.
Ok, syzbot is happy with this as well so let's get this fixed and backported,
tree: git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping.git branch: vfs.misc.fixes [1/1] fs: drop peer group ids under namespace lock commit: cb2239c198ad9fbd5aced22cf93e45562da781eb
linux-stable-mirror@lists.linaro.org