cgroup: add cgroup namespace to tree after owner is set

brauner · gregkh · commit d41ba8c6f667 · 2025-12-18T14:02:46.000+01:00
[ Upstream commit 768b156 ] Otherwise we trip VFS_WARN_ON_ONC() in __ns_tree_add_raw(). Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-6-2e6f823ebdc0@kernel.org Fixes: 7c60593 ("cgroup: support ns lookup") Tested-by: syzbot@syzkaller.appspotmail.com Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/kernel/cgroup/namespace.c b/kernel/cgroup/namespace.c
@@ -30,7 +30,6 @@ static struct cgroup_namespace *alloc_cgroup_ns(void)
 	ret = ns_common_init(new_ns);
 	if (ret)
 		return ERR_PTR(ret);
-	ns_tree_add(new_ns);
 	return no_free_ptr(new_ns);
 }
 
@@ -86,6 +85,7 @@ struct cgroup_namespace *copy_cgroup_ns(u64 flags,
 	new_ns->ucounts = ucounts;
 	new_ns->root_cset = cset;
 
+	ns_tree_add(new_ns);
 	return new_ns;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -30,7 +30,6 @@ static struct cgroup_namespace *alloc_cgroup_ns(void)`
`30`	`30`	`ret = ns_common_init(new_ns);`
`31`	`31`	`if (ret)`
`32`	`32`	`return ERR_PTR(ret);`
`33`		`- ns_tree_add(new_ns);`
`34`	`33`	`return no_free_ptr(new_ns);`
`35`	`34`	`}`
`36`	`35`
`@@ -86,6 +85,7 @@ struct cgroup_namespace *copy_cgroup_ns(u64 flags,`
`86`	`85`	`new_ns->ucounts = ucounts;`
`87`	`86`	`new_ns->root_cset = cset;`
`88`	`87`
	`88`	`+ ns_tree_add(new_ns);`
`89`	`89`	`return new_ns;`
`90`	`90`	`}`
`91`	`91`