netdev - Re: [PATCH net] page_pool: Fix 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: <a5cc7765-0de2-47ca-99c4-a48aaf6384d2@huawei.com>
Date: Fri, 23 May 2025 16:30:46 +0800
From: Yunsheng Lin <linyunsheng@...wei.com>
To: Dong Chenchen <dongchenchen2@...wei.com>, <hawk@...nel.org>,
	<ilias.apalodimas@...aro.org>, <davem@...emloft.net>, <edumazet@...gle.com>,
	<kuba@...nel.org>, <pabeni@...hat.com>, <horms@...nel.org>,
	<almasrymina@...gle.com>
CC: <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<zhangchangzhong@...wei.com>,
	<syzbot+204a4382fcb3311f3858@...kaller.appspotmail.com>
Subject: Re: [PATCH net] page_pool: Fix use-after-free in
 page_pool_recycle_in_ring

On 2025/5/23 14:45, Dong Chenchen wrote:

>  
>  static bool page_pool_recycle_in_ring(struct page_pool *pool, netmem_ref netmem)
>  {
> +	bool in_softirq;
>  	int ret;
int -> bool?

>  	/* BH protection not needed if current is softirq */
> -	if (in_softirq())
> -		ret = ptr_ring_produce(&pool->ring, (__force void *)netmem);
> -	else
> -		ret = ptr_ring_produce_bh(&pool->ring, (__force void *)netmem);
> -
> -	if (!ret) {
> +	in_softirq = page_pool_producer_lock(pool);
> +	ret = !__ptr_ring_produce(&pool->ring, (__force void *)netmem);
> +	if (ret)
>  		recycle_stat_inc(pool, ring);
> -		return true;
> -	}
> +	page_pool_producer_unlock(pool, in_softirq);
>  
> -	return false;
> +	return ret;
>  }
>  
>  /* Only allow direct recycling in special circumstances, into the
> @@ -1091,10 +1088,14 @@ static void page_pool_scrub(struct page_pool *pool)
>  
>  static int page_pool_release(struct page_pool *pool)
>  {
> +	bool in_softirq;
>  	int inflight;
>  
>  	page_pool_scrub(pool);
>  	inflight = page_pool_inflight(pool, true);
> +	/* Acquire producer lock to make sure producers have exited. */
> +	in_softirq = page_pool_producer_lock(pool);
> +	page_pool_producer_unlock(pool, in_softirq);

Is a compiler barrier needed to ensure compiler doesn't optimize away
the above code?

>  	if (!inflight)
>  		__page_pool_destroy(pool);
>