From: Eric Dumazet <eric.dumazet@gmail.com>
To: v.narang@samsung.com
Cc: Daniel Borkmann <daniel@iogearbox.net>,
Maninder Singh <maninder1.s@samsung.com>,
"davem@davemloft.net" <davem@davemloft.net>,
"willemb@google.com" <willemb@google.com>,
"edumazet@google.com" <edumazet@google.com>,
"eyal.birger@gmail.com" <eyal.birger@gmail.com>,
"tklauser@distanz.ch" <tklauser@distanz.ch>,
"fruggeri@aristanetworks.com" <fruggeri@aristanetworks.com>,
"dwmw2@infradead.org" <dwmw2@infradead.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
PANKAJ MISHRA <pankaj.m@samsung.com>,
Geon-ho Kim <gh007.kim@samsung.com>,
Hak-Bong Lee <hakbong5.lee@samsung.com>,
"ajeet.y@samsung.com" <ajeet.y@samsung.com>,
AKHILESH KUMAR <akhilesh.k@samsung.com>,
AMIT NAGAL <amit.nagal@samsung.com>
Subject: Re: [PATCH] af_packet: Raw socket destruction warning fix
Date: Wed, 10 Feb 2016 06:56:01 -0800 [thread overview]
Message-ID: <1455116161.19473.4.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <230561650.749911455108197509.JavaMail.weblogic@epmlwas05a>
On Wed, 2016-02-10 at 12:43 +0000, Vaneet Narang wrote:
> Hi,
>
> >What driver are you using (is that in-tree)? Can you reproduce the same issue
> >with a latest -net kernel, for example (or, a 'reasonably' recent one like 4.3 or
> >4.4)? There has been quite a bit of changes in err queue handling (which also
> >accounts rmem) as well. How reliably can you trigger the issue? Does it trigger
> >with a completely different in-tree network driver as well with your tests? Would
> >be useful to track/debug sk_rmem_alloc increases/decreases to see from which path
> >new rmem is being charged in the time between packet_release() and packet_sock_destruct()
> >for that socket ...
> >
> It seems race condition to us between packet_rcv and packet_close, we have tried to reproduce
> this issue by adding delay in skb_set_owner_r and issue gets reproduced quite frequently.
> we have added some traces and on analyzing we have realised following possible race condition.
Even if you add a delay in skb_set_owner_r(), this should not allow the
dismantle phase to complete, since at least one cpu is still in a
rcu_read_lock() section.
synchronize_rcu() must complete only when all cpus pass an rcu quiescent
point.
packet_close() should certainly not be called while another cpu is still
in the middle of packet_rcv()
Your patch does not address the root cause.
next prev parent reply other threads:[~2016-02-10 14:56 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-10 12:43 [PATCH] af_packet: Raw socket destruction warning fix Vaneet Narang
2016-02-10 14:56 ` Eric Dumazet [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-02-05 5:23 Vaneet Narang
2016-01-21 11:40 Maninder Singh
2016-01-26 0:13 ` Daniel Borkmann
2016-01-18 10:11 Vaneet Narang
2016-01-18 11:08 ` Daniel Borkmann
2016-01-18 6:37 Maninder Singh
2016-01-18 9:44 ` Daniel Borkmann
2016-01-18 10:29 ` Daniel Borkmann
2016-02-05 11:26 ` Eric Dumazet
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