From owner-freebsd-threads@FreeBSD.ORG Wed Jul 15 21:40:04 2009 Return-Path: Delivered-To: freebsd-threads@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4122310656DC for ; Wed, 15 Jul 2009 21:40:04 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 2F2DD8FC28 for ; Wed, 15 Jul 2009 21:40:04 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.3/8.14.3) with ESMTP id n6FLe4S9045880 for ; Wed, 15 Jul 2009 21:40:04 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.3/8.14.3/Submit) id n6FLe42l045879; Wed, 15 Jul 2009 21:40:04 GMT (envelope-from gnats) Date: Wed, 15 Jul 2009 21:40:04 GMT Message-Id: <200907152140.n6FLe42l045879@freefall.freebsd.org> To: freebsd-threads@FreeBSD.org From: Nick Esborn Cc: Subject: Re: threads/136345: Recursive read rwlocks in thread A cause deadlock with write lock in thread B X-BeenThere: freebsd-threads@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Nick Esborn List-Id: Threading on FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Jul 2009 21:40:04 -0000 The following reply was made to PR threads/136345; it has been noted by GNATS. From: Nick Esborn To: bug-followup@FreeBSD.org, rink@FreeBSD.org Cc: Subject: Re: threads/136345: Recursive read rwlocks in thread A cause deadlock with write lock in thread B Date: Wed, 15 Jul 2009 14:32:38 -0700 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --Apple-Mail-19-950902279 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Even after the above patch, I still run into occasional MySQL thread deadlocks, which I originally described in what is now threads/135673. I also posted on freebsd-current a few days ago: http://lists.freebsd.org/pipermail/freebsd-current/2009-July/009328.html I'd be happy to collect whatever data would be helpful in tracking down this deadlock. This only seems to happen under our production workload, so that might make it harder to capture meaningful debug data, but I'm certainly willing to try. I can also arrange for developer access to the system in question, if that would help significantly. -nick -- nick@desert.net - all messages cryptographically signed --Apple-Mail-19-950902279 content-type: application/pgp-signature; x-mac-type=70674453; name=PGP.sig content-description: This is a digitally signed message part content-disposition: inline; filename=PGP.sig content-transfer-encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Darwin) iEYEARECAAYFAkpeSvYACgkQw1bX5UNr2ABajACeNpj/MW4X+4zfvlWNCXnqo6D9 EZkAoLpGHxs4RoHMd7yqyba4IPzKxsJh =5I4q -----END PGP SIGNATURE----- --Apple-Mail-19-950902279--