netdev - Re: [BUG Report] KASAN: slab-use-after-free in page_pool_recycle_in

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250513142150.3cb416e1@kernel.org>
Date: Tue, 13 May 2025 14:21:50 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Mina Almasry <almasrymina@...gle.com>
Cc: Dong Chenchen <dongchenchen2@...wei.com>, hawk@...nel.org,
 ilias.apalodimas@...aro.org, davem@...emloft.net, edumazet@...gle.com,
 pabeni@...hat.com, horms@...nel.org, netdev@...r.kernel.org,
 linux-kernel@...r.kernel.org, zhangchangzhong@...wei.com
Subject: Re: [BUG Report] KASAN: slab-use-after-free in
 page_pool_recycle_in_ring

On Tue, 13 May 2025 13:06:38 -0700 Mina Almasry wrote:
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index 2b76848659418..8654608734773 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -1146,10 +1146,17 @@ static void page_pool_scrub(struct page_pool *pool)
> 
>  static int page_pool_release(struct page_pool *pool)
>  {
> +       bool in_softirq;
>         int inflight;
> 
> +
> +       /* Acquire producer lock to make sure we don't race with another thread
> +        * returning a netmem to the ptr_ring.
> +        */
> +       in_softirq = page_pool_producer_lock(pool);
>         page_pool_scrub(pool);
>         inflight = page_pool_inflight(pool, true);
> +       page_pool_producer_unlock(pool, in_softirq);

Makes sense! A couple minor notes.

Consumer lock should be outside, but really we only need to make 
sure producer has "exited" right? So lock/unlock, no need to wrap
any code in it.

I'd add a helper to ptr_ring.h, a "producer barrier" which just
takes/releases the producer lock. We can't be in softirq context
here but doesn't matter, let's take the lock in "any" mode IOW
irqsave() ?

The barrier is only needed if we're proceeding to destruction.
If inflight returns != 0 we won't destroy the pool so no need
to touch producer lock.