From: Eric Dumazet <dada1@cosmosbay•com>
To: Evgeniy Polyakov <johnpol@2ka•mipt.ru>
Cc: David Miller <davem@davemloft•net>,
axboe@kernel•dk, netdev@vger•kernel.org
Subject: Re: Fix for the fundamental network/block layer race in sendfile().
Date: Tue, 01 Apr 2008 22:59:18 +0200 [thread overview]
Message-ID: <47F2A226.60708@cosmosbay.com> (raw)
In-Reply-To: <20080401194527.GA26833@2ka.mipt.ru>
Evgeniy Polyakov a écrit :
> On Tue, Apr 01, 2008 at 09:21:19PM +0200, Eric Dumazet (dada1@cosmosbay•com) wrote:
>> I see no socket locking, so multiple threads could use sendfile() &
>> sendmsg() on same socket, and crash kernel...
>
> How?
> Those who use sendfile() automatically install page->lru.prev which is
> checked in release path, only those with given value will be processed
> as spliced (i.e. new callback).
>
> It is safe to install new callback on skbs which were not spliced, since
> for that skbs it will be pure sock_wfree().
>
first thread is doing its sendfile, and clears the bit while second thread
just entered sendfile() too, just after setting the bit and calling
do_splice_direct()
skb_set_owner_w() see the bit cleared, so install normal sock_wfree destructor
instead of sh_user_data.
crash or leak god_bless_us, you chose :)
next prev parent reply other threads:[~2008-04-01 20:59 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-28 9:20 Network/block layer race Evgeniy Polyakov
2008-03-28 20:40 ` David Miller
2008-03-28 20:56 ` Evgeniy Polyakov
2008-03-28 21:07 ` David Miller
2008-03-28 21:51 ` Evgeniy Polyakov
2008-04-01 16:49 ` Fix for the fundamental network/block layer race in sendfile() Evgeniy Polyakov
2008-04-01 17:14 ` Mika Penttilä
2008-04-01 17:36 ` Evgeniy Polyakov
2008-04-01 17:19 ` Eric Dumazet
2008-04-01 17:47 ` Evgeniy Polyakov
2008-04-01 18:07 ` Evgeniy Polyakov
2008-04-01 19:21 ` Eric Dumazet
2008-04-01 19:45 ` Evgeniy Polyakov
2008-04-01 20:59 ` Eric Dumazet [this message]
2008-04-01 21:14 ` Evgeniy Polyakov
2008-04-08 12:25 ` [take 2] " Evgeniy Polyakov
2008-04-08 12:58 ` Eric Dumazet
2008-04-08 17:26 ` Evgeniy Polyakov
2008-04-08 21:30 ` Evgeniy Polyakov
2008-04-09 11:33 ` Jens Axboe
2011-06-06 16:29 ` IPv6 DNSSL (rfc6106): please include the patch to pass it to user space Carlos Carvalho
2011-06-06 19:40 ` David Miller
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