Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: WARNING in sk_stream_kill_queues (5)
To:     Marco Elver <elver@google.com>, Eric Dumazet <edumazet@google.com>
Cc:     netdev <netdev@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Miller <davem@davemloft.net>,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Jann Horn <jannh@google.com>, Jakub Kicinski <kuba@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        Willem de Bruijn <willemb@google.com>,
        syzbot <syzbot+7b99aafdcc2eedea6178@syzkaller.appspotmail.com>
References: <000000000000b4862805b54ef573@google.com>
 <X8kLG5D+j4rT6L7A@elver.google.com>
 <CANn89iJWD5oXPLgtY47umTgo3gCGBaoy+XJfXnw1ecES_EXkCw@mail.gmail.com>
 <CANpmjNOaWbGJQ5Y=qC3cA31-R-Jy4Fbe+p=OBG5O2Amz8dLtLA@mail.gmail.com>
 <CANn89iKWf1EVZUuAHup+5ndhxvOqGopq53=vZ9yeok=DnRjggg@mail.gmail.com>
 <X8kjPIrLJUd8uQIX@elver.google.com>
From:   Eric Dumazet <eric.dumazet@gmail.com>
Message-ID: <af884a0e-5d4d-f71b-4821-b430ac196240@gmail.com>
Date:   Thu, 3 Dec 2020 19:01:21 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.4.0
MIME-Version: 1.0
In-Reply-To: <X8kjPIrLJUd8uQIX@elver.google.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 12/3/20 6:41 PM, Marco Elver wrote:

> One more experiment -- simply adding
> 
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -207,7 +207,21 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
>  	 */
>  	size = SKB_DATA_ALIGN(size);
>  	size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
> +	size = 1 << kmalloc_index(size); /* HACK */
>  	data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
> 
> 
> also got rid of the warnings. Something must be off with some value that
> is computed in terms of ksize(). If not, I don't have any explanation
> for why the above hides the problem.

Maybe the implementations of various macros (SKB_DATA_ALIGN and friends)
hae some kind of assumptions, I will double check this.