Re: namespaces?: bug at mm/slub.c:2750

[David Howells]

Serge E. Hallyn <serue@xxxxxxxxxx> wrote:

> Yes, but noone will pull the user_struct off the list without
> taking the lock.
> 
> what am I missing?

I believe that the hash link (uidhash_node) in the user_struct that is passed
to uid_hash_remove() points to, and is pointed to by the user_namespace to
which the user_struct belongs.

In which case calling put_user_ns() may kfree the head pointer of the list
_before_ hlist_del_init() is invoked - in which case hlist_del_init() will act
upon freed memory.

At least, I think it works like this.


Anyway, I have no objection to your new patch.

Acked-by: David Howells <dhowells@xxxxxxxxxx>
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