Date: Mon, 15 Feb 2016 02:33:11 +0000 (UTC) From: Greg Quinlan <gwq_uk@yahoo.com> To: Hans Petter Selasky <hps@selasky.org>, "freebsd-current@freebsd.org" <freebsd-current@freebsd.org> Subject: Re: Open Sound System - OSS "soundon" command causes KERNEL PANIC FreeBSD-11 Message-ID: <693932216.4173309.1455503591733.JavaMail.yahoo@mail.yahoo.com> In-Reply-To: <56BEE187.80702@selasky.org> References: <56BEE187.80702@selasky.org>
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Thanks.=20 I am not going to use OSS anymore...=C2=A0=20 I am going to stick to stick with a custom kernel device sounddevice snd_hda=C2=A0From: Hans Petter Selasky <hps@selasky.org> To: Greg Quinlan <gwq_uk@yahoo.com>; "freebsd-current@freebsd.org" <freebs= d-current@freebsd.org>=20 Sent: Saturday, 13 February 2016, 18:55 Subject: Re: Open Sound System - OSS "soundon" command causes KERNEL PANIC= FreeBSD-11 =20 On 02/12/16 01:04, Greg Quinlan wrote: > Spoke too soon... > > I applied the patch (kern_module.diff - which was successful) > > # cd /usr/src# patch <kern_module.diffHmm...=C2=A0 Looks like a unified d= iff to me... > The text leading up to this was: > -------------------------- > |Index: sys/kern/kern_module.c > |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > |--- sys/kern/kern_module.c=C2=A0 =C2=A0 (revision 295464) > |+++ sys/kern/kern_module.c=C2=A0 =C2=A0 (working copy) > -------------------------- > Patching file sys/kern/kern_module.c using Plan A... > Hunk #1 succeeded at 214. > done > # make buildkernel: > # make installkernel: > # shutdown -r now > Logged in and ran# soundon > No panic!! > > Thought the problem was fixed ... unfortunately, I assumed that the conte= nts of /usr/local/lib/oss/etc/installed_drivers still contained >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 oss_hdaudio #Intel High Definition Audi= o (CPT) > but somehow the file was empty > I ran >=C2=A0 =C2=A0 =C2=A0 # ossdetect=C2=A0 =C2=A0 # soundon > > Another KERNEL PANIC...=C2=A0 this time it scrolled off the screen. I tri= ed setting this (below) in /etc/rc.conf but there is nothing in /var/crash > > [entries in /etc/rc.conf] >=C2=A0 =C2=A0 =C2=A0 dumpdev=3D"AUTO" >=C2=A0 =C2=A0 =C2=A0 dumpdir=3D"/var/crash" > I need help to recover the backtrace, please? > > Thanks > >=C2=A0 =C2=A0 =C2=A0 =C2=A0 From: Greg Quinlan <gwq_uk@yahoo.com> > To: Hans Petter Selasky <hps@selasky.org>; "freebsd-current@freebsd.org" = <freebsd-current@freebsd.org> >=C2=A0 Sent: Thursday, 11 February 2016, 22:19 >=C2=A0 Subject: Re: Open Sound System - OSS "soundon" command causes KERNE= L PANIC FreeBSD-11 > > Well done!! > Fixed. Thanks! > > > >=C2=A0 =C2=A0 =C2=A0 =C2=A0 From: Hans Petter Selasky <hps@selasky.org> >=C2=A0 To: Greg Quinlan <gwq_uk@yahoo.com>; "freebsd-current@freebsd.org" = <freebsd-current@freebsd.org> >=C2=A0 Sent: Thursday, 11 February 2016, 17:54 >=C2=A0 Subject: Re: Open Sound System - OSS "soundon" command causes KERNE= L PANIC FreeBSD-11 > > On 02/11/16 03:02, Greg Quinlan wrote: >> Hi HPS, >> Note: Does not happen on FreeBSD 10.1-Stable! >> > > Yes, that's because WITNESS is off in 10.x by default. > > Does the attached patch solve your problem? > > --HPS Hi, It might be that audio/oss is not compatible with 11-current if it=20 crashes like that. --HPS _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" From owner-freebsd-current@freebsd.org Mon Feb 15 09:08:36 2016 Return-Path: <owner-freebsd-current@freebsd.org> Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 32191AA6A2C for <freebsd-current@mailman.ysv.freebsd.org>; Mon, 15 Feb 2016 09:08:36 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id 51E4A1AC4; Mon, 15 Feb 2016 09:08:35 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from porto.starpoint.kiev.ua (porto-e.starpoint.kiev.ua [212.40.38.100]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id LAA04012; Mon, 15 Feb 2016 11:08:32 +0200 (EET) (envelope-from avg@FreeBSD.org) Received: from localhost ([127.0.0.1]) by porto.starpoint.kiev.ua with esmtp (Exim 4.34 (FreeBSD)) id 1aVF8y-000LMO-FA; Mon, 15 Feb 2016 11:08:32 +0200 Subject: Re: Memory modified after free in "MAP ENTRY" zone (vm_map_entry_t->read_ahead) To: alc@FreeBSD.org References: <56BBAB6E.5050601@FreeBSD.org> <56C08AAA.5050206@FreeBSD.org> <CAJUyCcNy19rArmgjzpPZvsDE7Ln4OoMWU+75Q+THdp0T7+DxPg@mail.gmail.com> Cc: FreeBSD Current <freebsd-current@FreeBSD.org> From: Andriy Gapon <avg@FreeBSD.org> X-Enigmail-Draft-Status: N1110 Message-ID: <56C1953F.60604@FreeBSD.org> Date: Mon, 15 Feb 2016 11:07:11 +0200 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: <CAJUyCcNy19rArmgjzpPZvsDE7Ln4OoMWU+75Q+THdp0T7+DxPg@mail.gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussions about the use of FreeBSD-current <freebsd-current.freebsd.org> List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-current>, <mailto:freebsd-current-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current/>; List-Post: <mailto:freebsd-current@freebsd.org> List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help> List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-current>, <mailto:freebsd-current-request@freebsd.org?subject=subscribe> X-List-Received-Date: Mon, 15 Feb 2016 09:08:36 -0000 On 15/02/2016 00:27, Alan Cox wrote: > > On Sun, Feb 14, 2016 at 8:09 AM, Andriy Gapon <avg@freebsd.org > <mailto:avg@freebsd.org>> wrote: > > On 10/02/2016 23:28, Andriy Gapon wrote: > > > > Over a span of approximately 3 weeks I have got two slightly different panics of > > the same kind. The affected system is a several months old amd64 head. > > I added a small assertion and it got tripped: [snip] > > So, it seems that the code allows modification of read_ahead field of an entry > without holding a map lock. I'd guess that that should be mostly harmless as > read_ahead value is not critical, but it is still not nice. > > Not intentionally. The nearby code to the read_ahead assignment expects the map > to be locked, so I wouldn't categorize this as mostly harmless. > > In general, you shouldn't get to the read_ahead assignment without the map being > locked, and almost all of the code paths that unlock the map jump to RetryFault > shortly thereafter, so it's hard to imagine how the map lock wouldn't be > reacquired. I speculate that the root cause of your panic is a case where > vm_pager_get_pages() fails, and in such a case we might loop around, descending > to the next backing object without reacquiring the map lock. In other words, > your above assertion failure is happening on the next iteration after an initial > vm_pager_get_pages() failure, and we're about to do another vm_pager_get_pages() > call on a different object. > > In summary, I have no trouble believing that the code that handles a failure by > vm_pager_get_pages() in vm_fault() is not quite right, and I think that's what's > biting you. Alan, thank you very much for the very insightful analysis. Indeed, I see that in this case the object chain is default -> swap -> swap. I am not sure how such chain was created. It seems that going default -> swap is not a problem as the map lock is not dropped in this case. But going swap -> swap the way you described (pager error, e.g. the page is just not found) has exactly the problem that you suggested. -- Andriy Gapon
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