Re: [syzbot] [fs?] WARNING in nsproxy_ns_active_put

From: Christian Brauner

Date: Tue Nov 11 2025 - 10:07:11 EST


On Tue, Nov 11, 2025 at 05:03:03AM -0800, syzbot wrote:
> Hello,
>
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> WARNING in __ns_ref_active_put

#syz test: https://github.com/brauner/linux.git namespace-6.19

Groan, forgot the actual important bit after the cleanup:

* Called from unshare. Unshare all the namespaces part of nsproxy.
* On success, returns the new nsproxy.
@@ -338,7 +313,7 @@ static void put_nsset(struct nsset *nsset)
if (nsset->fs && (flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS))
free_fs_struct(nsset->fs);
if (nsset->nsproxy)
- free_nsproxy(nsset->nsproxy);
+ nsproxy_free(nsset->nsproxy);
}