netdev - Re: [bpf-next PATCH] bpf: sockmap, fix skmsg recvmsg handler to track size correctly

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Message-ID: <4e315066-0dd3-d39a-9f07-3e5dee876ab0@iogearbox.net>
Date:   Wed, 17 Oct 2018 02:32:52 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     John Fastabend <john.fastabend@...il.com>, ast@...nel.org
Cc:     netdev@...r.kernel.org
Subject: Re: [bpf-next PATCH] bpf: sockmap, fix skmsg recvmsg handler to track
 size correctly

On 10/16/2018 07:36 PM, John Fastabend wrote:
> When converting sockmap to new skmsg generic data structures we missed
> that the recvmsg handler did not correctly use sg.size and instead was
> using individual elements length. The result is if a sock is closed
> with outstanding data we omit the call to sk_mem_uncharge() and can
> get the warning below.
> 
> [   66.728282] WARNING: CPU: 6 PID: 5783 at net/core/stream.c:206 sk_stream_kill_queues+0x1fa/0x210
> 
> To fix this correct the redirect handler to xfer the size along with
> the scatterlist and also decrement the size from the recvmsg handler.
> Now when a sock is closed the remaining 'size' will be decremented
> with sk_mem_uncharge().
> 
> Signed-off-by: John Fastabend <john.fastabend@...il.com>

Applied to bpf-next, thanks!