Date: Sat, 8 Sep 2007 21:17:26 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Maxim Sobolev <sobomax@freebsd.org> Cc: stable@freebsd.org Subject: Re: kqueue LOR Message-ID: <20070908181726.GR53667@deviant.kiev.zoral.com.ua> In-Reply-To: <46E25620.6050906@FreeBSD.org> References: <46E19D4E.1060009@FreeBSD.org> <20070908040233.GP53667@deviant.kiev.zoral.com.ua> <46E25620.6050906@FreeBSD.org>
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--Pa4xkLBhPDIhDLv1 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Sep 08, 2007 at 12:58:24AM -0700, Maxim Sobolev wrote: > Kostik Belousov wrote: > >On Fri, Sep 07, 2007 at 11:49:50AM -0700, Maxim Sobolev wrote: > >>Hi, > >> > >>On my 6.2 system I am seeing LOR discussed almost 1 year ago here: > >> > >>http://lists.freebsd.org/pipermail/freebsd-stable/2006-November/031048.= html > >>http://lists.freebsd.org/pipermail/freebsd-stable/2006-December/031197.= html > >> > >>lock order reversal: > >> 1st 0xc52cb500 kqueue (kqueue) @ kern/kern_event.c:1547 > >> 2nd 0xc4e4d80c struct mount mtx (struct mount mtx) @=20 > >>ufs/ufs/ufs_vnops.c:138 > >> > >>Do you have any plans to commit the suggested fix? > >I suspect that the LOR is bogus. I was never able to get the information > >where the reverse lock order happen. What I asked of the most reporters = is > >to apply sys/kern/subr_witness.c rev. 1.222 to RELENG_6 and provide me > >with the LOR report, if any. >=20 > What do you mean "bogus"? It happens reliably on my system. Bogus means that reported LOR, most likely, do not cause actual deadlock. >=20 > >Note that doing that on RELENG_6_2 makes no sense, most likely you will > >get LORs with cdev mutex, fixed in RELENG_6. >=20 > I don't quite understand that. RELENG_6_2 had known LOR that already was fixed in RELENG_6, between cdev mutex and and sleep mtxpool, namely LOR #197. After user have applyed rev. 1.222 of subr_witness, I usuallygot the reports of that LOR, if any, but not the LOR I needed. --Pa4xkLBhPDIhDLv1 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQFG4uc1C3+MBN1Mb4gRAm1lAKCYjRK37Y0e4T8bTcc4IgTcWbihMwCdFvx/ OOdhjqemRPR1JIiH5ls32VQ= =esTX -----END PGP SIGNATURE----- --Pa4xkLBhPDIhDLv1--
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