From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Dufour Subject: Re: kernel BUG at drivers/scsi/scsi_lib.c:1096! Date: Sat, 21 Nov 2015 12:30:14 +0100 Message-ID: <565055C6.5040801@linux.vnet.ibm.com> References: <1447838334.1564.2.camel@ellerman.id.au> <1447855399.3974.24.camel@redhat.com> <1447894964.15206.0.camel@ellerman.id.au> <20151119082325.GA11419@infradead.org> <1448021448.14769.7.camel@ellerman.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <1448021448.14769.7.camel@ellerman.id.au> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org Sender: "Linuxppc-dev" To: Michael Ellerman , Ming Lei Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, "James E. J. Bottomley" , linux-kernel@vger.kernel.org, Christoph Hellwig , brking , Mark Salter , linuxppc-dev@lists.ozlabs.org List-Id: linux-scsi@vger.kernel.org T24gMjAvMTEvMjAxNSAxMzoxMCwgTWljaGFlbCBFbGxlcm1hbiB3cm90ZToKPiBPbiBUaHUsIDIw MTUtMTEtMTkgYXQgMDA6MjMgLTA4MDAsIENocmlzdG9waCBIZWxsd2lnIHdyb3RlOgo+IAo+PiBJ dCdzIHByZXR0eSBtdWNoIGd1YXJhbnRlZWQgYSBibG9jayBsYXllciBidWcsIG1vc3QgbGlrZWx5 IGluIHRoZQo+PiBtZXJnZSBiaW9zIHRvIHJlcXVlc3QgaW5mcmFzdHVjdHVyZSB3aGVyZSB3ZSBk b24ndCBvYmV5IHRoZSBtZXJnaW5nCj4+IGxpbWl0cyBwcm9wZXJseS4KPj4KPj4gRG9lcyBlaXRo ZXIgb2YgeW91IGhhdmUgYSBrbm93biBnb29kIGFuZCBmaXJzdCBrbm93biBiYWQga2VybmVsPwo+ IAo+IE5vdCBtZSwgSSd2ZSBvbmx5IGhpdCBpdCBvbmUgb3IgdHdvIHRpbWVzLiBBbGwgSSBjYW4g c2F5IGlzIEkgaGF2ZSBoaXQgaXQgaW4KPiA0LjQtcmMxLgo+IAo+IExhdXJlbnQsIGNhbiB5b3Ug bmFycm93IGl0IGRvd24gYXQgYWxsPwoKSXQgc2VlbXMgdGhhdCB0aGUgcGFuaWMgaXMgdHJpZ2dl cmVkIGJ5IHRoZSBjb21taXQgYmRjZWQ0MzhhY2Q4ICgiYmxvY2s6CnNldHVwIGJpX3BoeXNfc2Vn bWVudHMgYWZ0ZXIgc3BsaXR0aW5nIikgd2hpY2ggaGFzIGJlZW4gcHVsbGVkIGJ5IHRoZQptZXJn ZSBkOTczNGUwZDFjY2YgKCJNZXJnZSBicmFuY2ggJ2Zvci00LjQvY29yZScgb2YKZ2l0Oi8vZ2l0 Lmtlcm5lbC5kay9saW51eC1ibG9jayIpLgoKTXkgc3lzdGVtIGlzIHBhbmljaW5nIHByb21wdGx5 IHdoZW4gcnVubmluZyBhIGtlcm5lbCBidWlsdCBhdApkOTczNGUwZDFjY2YsIHdoaWxlIHJldmVy dGluZyB0aGUgY29tbWl0IGJkY2VkNDM4YWNkOCwgaXQgY2FuIHJ1biBob3Vycwp3aXRob3V0IHBh bmljaW5nLgoKVGhpcyBiZWluZyBzYWlkLCBJIGNhbid0IGV4cGxhaW4gd2hhdCdzIGdvaW5nIHdy b25nLgoKTWF5IE1pbmcgc2hlZCBzb21lIGxpZ2h0IGhlcmUgPwoKQ2hlZXJzCgoKX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KTGludXhwcGMtZGV2IG1haWxp bmcgbGlzdApMaW51eHBwYy1kZXZAbGlzdHMub3psYWJzLm9yZwpodHRwczovL2xpc3RzLm96bGFi cy5vcmcvbGlzdGluZm8vbGludXhwcGMtZGV2 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e06smtp08.uk.ibm.com (e06smtp08.uk.ibm.com [195.75.94.104]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 20B641A0100 for ; Sat, 21 Nov 2015 22:30:23 +1100 (AEDT) Received: from localhost by e06smtp08.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 21 Nov 2015 11:30:19 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 80BF01B0805F for ; Sat, 21 Nov 2015 11:30:38 +0000 (GMT) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id tALBUGSs10158566 for ; Sat, 21 Nov 2015 11:30:17 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id tALBUFnY026760 for ; Sat, 21 Nov 2015 04:30:16 -0700 Subject: Re: kernel BUG at drivers/scsi/scsi_lib.c:1096! To: Michael Ellerman , Ming Lei References: <1447838334.1564.2.camel@ellerman.id.au> <1447855399.3974.24.camel@redhat.com> <1447894964.15206.0.camel@ellerman.id.au> <20151119082325.GA11419@infradead.org> <1448021448.14769.7.camel@ellerman.id.au> Cc: Christoph Hellwig , Mark Salter , "James E. J. Bottomley" , brking , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-block@vger.kernel.org From: Laurent Dufour Message-ID: <565055C6.5040801@linux.vnet.ibm.com> Date: Sat, 21 Nov 2015 12:30:14 +0100 MIME-Version: 1.0 In-Reply-To: <1448021448.14769.7.camel@ellerman.id.au> Content-Type: text/plain; charset=utf-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 20/11/2015 13:10, Michael Ellerman wrote: > On Thu, 2015-11-19 at 00:23 -0800, Christoph Hellwig wrote: > >> It's pretty much guaranteed a block layer bug, most likely in the >> merge bios to request infrastucture where we don't obey the merging >> limits properly. >> >> Does either of you have a known good and first known bad kernel? > > Not me, I've only hit it one or two times. All I can say is I have hit it in > 4.4-rc1. > > Laurent, can you narrow it down at all? It seems that the panic is triggered by the commit bdced438acd8 ("block: setup bi_phys_segments after splitting") which has been pulled by the merge d9734e0d1ccf ("Merge branch 'for-4.4/core' of git://git.kernel.dk/linux-block"). My system is panicing promptly when running a kernel built at d9734e0d1ccf, while reverting the commit bdced438acd8, it can run hours without panicing. This being said, I can't explain what's going wrong. May Ming shed some light here ? Cheers