From: Alan Modra <amodra@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev <netdev@vger.kernel.org>,
Ambrose Feinstein <ambrose@google.com>,
Paul Mackerras <paulus@samba.org>,
Anton Blanchard <anton@samba.org>,
linuxppc-dev@lists.ozlabs.org, David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next] af_unix: fix a fatal race with bit fields
Date: Fri, 3 May 2013 11:01:36 +0930 [thread overview]
Message-ID: <20130503013136.GN5221@bubble.grove.modra.org> (raw)
In-Reply-To: <1367384672.11020.34.camel@edumazet-glaptop>
On Tue, Apr 30, 2013 at 10:04:32PM -0700, Eric Dumazet wrote:
> These kind of errors are pretty hard to find, its a pity to spend time
> on them.
Well, yes. From the first comment in gcc PR52080. "For the following
testcase we generate a 8 byte RMW cycle on IA64 which causes locking
problems in the linux kernel btrfs filesystem."
Did someone fix btrfs, but not check other kernel locks? Having now
hit the same problem again, have you checked that other kernel locks
don't have adjacent bit fields in the same 64-bit word? And comment
the struct to ensure someone doesn't optimize those unsigned chars
back to bit fields.
--
Alan Modra
Australia Development Lab, IBM
next prev parent reply other threads:[~2013-05-03 1:31 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-01 1:12 [PATCH net-next] af_unix: fix a fatal race with bit fields Eric Dumazet
2013-05-01 1:39 ` Benjamin Herrenschmidt
2013-05-01 7:36 ` David Miller
2013-05-01 8:08 ` Benjamin Herrenschmidt
2013-05-01 15:24 ` [PATCH v2 " Eric Dumazet
2013-05-01 15:53 ` David Laight
2013-05-01 16:00 ` Eric Dumazet
2013-05-01 19:14 ` David Miller
2013-05-01 12:08 ` [PATCH " Ben Hutchings
2013-05-03 14:29 ` David Laight
2013-05-03 15:02 ` Eric Dumazet
2013-05-03 15:44 ` David Laight
2013-05-01 1:51 ` Anton Blanchard
2013-05-01 2:24 ` Eric Dumazet
2013-05-01 3:54 ` Alan Modra
2013-05-01 5:04 ` Eric Dumazet
2013-05-01 15:10 ` Stephen Hemminger
2013-05-02 21:11 ` Benjamin Herrenschmidt
2013-05-03 1:31 ` Alan Modra [this message]
2013-05-03 8:20 ` David Laight
2013-05-03 12:57 ` Benjamin Herrenschmidt
2013-05-03 14:14 ` Eric Dumazet
2013-05-02 17:02 ` Scott Wood
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