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From: David Miller <davem@davemloft.net>
To: asmadeus@codewreck.org
Cc: doronrk@fb.com, tom@quantonium.net, davejwatson@fb.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] kcm: remove any offset before parsing messages
Date: Mon, 17 Sep 2018 18:45:02 -0700 (PDT) [thread overview]
Message-ID: <20180917.184502.447385458615284933.davem@davemloft.net> (raw)
In-Reply-To: <20180912053642.GA2912@nautica>
From: Dominique Martinet <asmadeus@codewreck.org>
Date: Wed, 12 Sep 2018 07:36:42 +0200
> Dominique Martinet wrote on Tue, Sep 11, 2018:
>> Hmm, while trying to benchmark this, I sometimes got hangs in
>> kcm_wait_data() for the last packet somehow?
>> The sender program was done (exited (zombie) so I assumed the sender
>> socket flushed), but the receiver was in kcm_wait_data in kcm_recvmsg
>> indicating it parsed a header but there was no skb to peek at?
>> But the sock is locked so this shouldn't be racy...
>>
>> I can get it fairly often with this patch and small messages with an
>> offset, but I think it's just because the pull changes some timing - I
>> can't hit it with just the clone, and I can hit it with a pull without
>> clone as well.... And I don't see how pulling a cloned skb can impact
>> the original socket, but I'm a bit fuzzy on this.
>
> This is weird, I cannot reproduce at all without that pull, even if I
> add another delay there instead of the pull, so it's not just timing...
I really can't apply this patch until you resolve this.
It is weird, given your description, though...
next prev parent reply other threads:[~2018-09-18 1:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-11 9:21 Dominique Martinet
2018-09-12 5:36 ` Dominique Martinet
2018-09-18 1:45 ` David Miller [this message]
2018-09-18 1:57 ` Dominique Martinet
2018-09-18 2:40 ` David Miller
2018-09-18 2:45 ` Dominique Martinet
2018-09-18 2:51 ` David Miller
2018-09-18 2:58 ` Dominique Martinet
2018-10-31 2:56 ` Dominique Martinet
2019-02-15 1:00 ` Dominique Martinet
2019-02-15 1:20 ` Tom Herbert
2019-02-15 1:57 ` Dominique Martinet
2019-02-15 2:48 ` Tom Herbert
2019-02-15 3:31 ` Dominique Martinet
2019-02-15 4:01 ` Tom Herbert
2019-02-15 4:52 ` Dominique Martinet
2019-02-20 4:11 ` Dominique Martinet
2019-02-20 16:18 ` Tom Herbert
2019-02-21 8:22 ` Dominique Martinet
2019-02-22 19:24 ` Tom Herbert
2019-02-22 20:27 ` Dominique Martinet
2019-02-22 21:01 ` Tom Herbert
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