From: Russ Cox <rsc@swtch.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] interesting deadlock
Date: Fri, 17 Sep 2010 19:21:38 -0400 [thread overview]
Message-ID: <AANLkTikjAzEmL8XWvPogqCvdmVkravevP5WE77EP0D+T@mail.gmail.com> (raw)
In-Reply-To: <ba77339bbbbb714318b904a9951d7e49@coraid.com>
> of mh->mount, which is nil. the code in question
> was a fileserver which was crashing, getting killed
> while concurrent io was being done to the fs.
i believe that. the code is assuming that because
it found mh in the mount table, mh->mount != nil.
that's only true until it releases the rlock, which it has.
if an unmount happens between the runlock and the
rlock, then mh->mount will be nil here. it means
that nothing is mounted there anymore. your fix
looks reasonable.
russ
next prev parent reply other threads:[~2010-09-17 23:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-17 3:02 erik quanstrom
2010-09-17 21:11 ` Russ Cox
2010-09-17 22:12 ` erik quanstrom
2010-09-17 23:21 ` Russ Cox [this message]
2010-09-17 23:57 ` erik quanstrom
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