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: Mon, 23 Nov 2015 14:57:19 +0100 Message-ID: <56531B3F.60503@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> <565055C6.5040801@linux.vnet.ibm.com> <20151122005635.1b9ffbe1@tom-T450> <1448234410.8209.3.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <1448234410.8209.3.camel@redhat.com> 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: Mark Salter , Ming Lei Cc: Christoph Hellwig , linux-scsi@vger.kernel.org, tom.leiming@gmail.com, "James E. J. Bottomley" , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, brking , linuxppc-dev@lists.ozlabs.org List-Id: linux-scsi@vger.kernel.org T24gMjMvMTEvMjAxNSAwMDoyMCwgTWFyayBTYWx0ZXIgd3JvdGU6Cj4gT24gU3VuLCAyMDE1LTEx LTIyIGF0IDAwOjU2ICswODAwLCBNaW5nIExlaSB3cm90ZToKPj4gT24gU2F0LCAyMSBOb3YgMjAx NSAxMjozMDoxNCArMDEwMAo+PiBMYXVyZW50IER1Zm91ciA8bGR1Zm91ckBsaW51eC52bmV0Lmli bS5jb20+IHdyb3RlOgo+Pgo+Pj4gT24gMjAvMTEvMjAxNSAxMzoxMCwgTWljaGFlbCBFbGxlcm1h biB3cm90ZToKPj4+PiBPbiBUaHUsIDIwMTUtMTEtMTkgYXQgMDA6MjMgLTA4MDAsIENocmlzdG9w aCBIZWxsd2lnIHdyb3RlOgo+Pj4+Cj4+Pj4+IEl0J3MgcHJldHR5IG11Y2ggZ3VhcmFudGVlZCBh IGJsb2NrIGxheWVyIGJ1ZywgbW9zdCBsaWtlbHkgaW4gdGhlCj4+Pj4+IG1lcmdlIGJpb3MgdG8g cmVxdWVzdCBpbmZyYXN0dWN0dXJlIHdoZXJlIHdlIGRvbid0IG9iZXkgdGhlIG1lcmdpbmcKPj4+ Pj4gbGltaXRzIHByb3Blcmx5Lgo+Pj4+Pgo+Pj4+PiBEb2VzIGVpdGhlciBvZiB5b3UgaGF2ZSBh IGtub3duIGdvb2QgYW5kIGZpcnN0IGtub3duIGJhZCBrZXJuZWw/Cj4+Pj4KPj4+PiBOb3QgbWUs IEkndmUgb25seSBoaXQgaXQgb25lIG9yIHR3byB0aW1lcy4gQWxsIEkgY2FuIHNheSBpcyBJIGhh dmUgaGl0IGl0IGluCj4+Pj4gNC40LXJjMS4KPj4+Pgo+Pj4+IExhdXJlbnQsIGNhbiB5b3UgbmFy cm93IGl0IGRvd24gYXQgYWxsPwo+Pj4KPj4+IEl0IHNlZW1zIHRoYXQgdGhlIHBhbmljIGlzIHRy aWdnZXJlZCBieSB0aGUgY29tbWl0IGJkY2VkNDM4YWNkOCAoImJsb2NrOgo+Pj4gc2V0dXAgYmlf cGh5c19zZWdtZW50cyBhZnRlciBzcGxpdHRpbmciKSB3aGljaCBoYXMgYmVlbiBwdWxsZWQgYnkg dGhlCj4+PiBtZXJnZSBkOTczNGUwZDFjY2YgKCJNZXJnZSBicmFuY2ggJ2Zvci00LjQvY29yZScg b2YKPj4+IGdpdDovL2dpdC5rZXJuZWwuZGsvbGludXgtYmxvY2siKS4KPj4+Cj4+PiBNeSBzeXN0 ZW0gaXMgcGFuaWNpbmcgcHJvbXB0bHkgd2hlbiBydW5uaW5nIGEga2VybmVsIGJ1aWx0IGF0Cj4+ PiBkOTczNGUwZDFjY2YsIHdoaWxlIHJldmVydGluZyB0aGUgY29tbWl0IGJkY2VkNDM4YWNkOCwg aXQgY2FuIHJ1biBob3Vycwo+Pj4gd2l0aG91dCBwYW5pY2luZy4KPj4+Cj4+PiBUaGlzIGJlaW5n IHNhaWQsIEkgY2FuJ3QgZXhwbGFpbiB3aGF0J3MgZ29pbmcgd3JvbmcuCj4+Pgo+Pj4gTWF5IE1p bmcgc2hlZCBzb21lIGxpZ2h0IGhlcmUgPwo+Pgo+PiBMYXVyZW50LCBsb29rcyB0aGVyZSBpcyBv bmUgYnVnIGluIGJsa19iaW9fc2VnbWVudF9zcGxpdCgpLCB3b3VsZCB5b3UKPj4gbWluZCB0ZXN0 aW5nIHRoZSBmb2xsb3dpbmcgcGF0Y2ggdG8gc2VlIGlmIGl0IGZpeGVzIHlvdXIgaXNzdWU/Cj4+ Cj4+IC0tLQo+PiBGcm9tIDZmYzcwMTIzMWRjYzAwMGJjOGJjNGI5MTA1NTgzMzgwZDlhYTMxZjQg TW9uIFNlcCAxNyAwMDowMDowMCAyMDAxCj4+IEZyb206IE1pbmcgTGVpIDxtaW5nLmxlaUBjYW5v bmljYWwuY29tPgo+PiBEYXRlOiBTdW4sIDIyIE5vdiAyMDE1IDAwOjQ3OjEzICswODAwCj4+IFN1 YmplY3Q6IFtQQVRDSF0gYmxvY2s6IGZpeCBzZWdtZW50IHNwbGl0Cj4+Cj4+IEluc2lkZSBibGtf YmlvX3NlZ21lbnRfc3BsaXQoKSwgcHJldmlvdXMgYnZlYyBwb2ludGVyKCdidnBydnAnKQo+PiBh bHdheXMgcG9pbnRzIHRvIHRoZSBpdGVyYXRvciBsb2NhbCB2YXJpYWJsZSwgd2hpY2ggaXMgb2J2 aW91c2x5Cj4+IHdyb25nLCBzbyBmaXggaXQgYnkgcG9pbnRpbmcgdG8gdGhlIGxvY2FsIHZhcmlh YmxlIG9mICdidnBydicuCj4+Cj4+IFNpZ25lZC1vZmYtYnk6IE1pbmcgTGVpIDxtaW5nLmxlaUBj YW5vbmljYWwuY29tPgo+PiAtLS0KPj4gIGJsb2NrL2Jsay1tZXJnZS5jIHwgNCArKy0tCj4+ICAx IGZpbGUgY2hhbmdlZCwgMiBpbnNlcnRpb25zKCspLCAyIGRlbGV0aW9ucygtKQo+Pgo+PiBkaWZm IC0tZ2l0IGEvYmxvY2svYmxrLW1lcmdlLmMgYi9ibG9jay9ibGstbWVyZ2UuYwo+PiBpbmRleCBk ZTU3MTZkOC4uZjJlZmU4YSAxMDA2NDQKPj4gLS0tIGEvYmxvY2svYmxrLW1lcmdlLmMKPj4gKysr IGIvYmxvY2svYmxrLW1lcmdlLmMKPj4gQEAgLTk4LDcgKzk4LDcgQEAgc3RhdGljIHN0cnVjdCBi aW8gKmJsa19iaW9fc2VnbWVudF9zcGxpdChzdHJ1Y3QgcmVxdWVzdF9xdWV1ZSAqcSwKPj4gIAo+ PiAgCQkJc2VnX3NpemUgKz0gYnYuYnZfbGVuOwo+PiAgCQkJYnZwcnYgPSBidjsKPj4gLQkJCWJ2 cHJ2cCA9ICZidjsKPj4gKwkJCWJ2cHJ2cCA9ICZidnBydjsKPj4gIAkJCXNlY3RvcnMgKz0gYnYu YnZfbGVuID4+IDk7Cj4+ICAJCQljb250aW51ZTsKPj4gIAkJfQo+PiBAQCAtMTA4LDcgKzEwOCw3 IEBAIG5ld19zZWdtZW50Ogo+PiAgCj4+ICAJCW5zZWdzKys7Cj4+ICAJCWJ2cHJ2ID0gYnY7Cj4+ IC0JCWJ2cHJ2cCA9ICZidjsKPj4gKwkJYnZwcnZwID0gJmJ2cHJ2Owo+PiAgCQlzZWdfc2l6ZSA9 IGJ2LmJ2X2xlbjsKPj4gIAkJc2VjdG9ycyArPSBidi5idl9sZW4gPj4gOTsKPj4gIAl9Cj4gCj4g SSdtIHN0aWxsIGhpdHRpbmcgdGhlIEJVRyBldmVuIHdpdGggdGhpcyBwYXRjaCBhcHBsaWVkIG9u IHRvcCBvZiA0LjQtcmMxLgoKT24gbXkgc2lkZSwgd2l0aCB0aGUgcGF0Y2ggYXBwbGllZCBvbiB0 b3Agb2YgNC40LXJjMSwgSSBjYW4ndCBnZXQgdGhlCnBhbmljIGFueW1vcmUuCgoKX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KTGludXhwcGMtZGV2IG1haWxp bmcgbGlzdApMaW51eHBwYy1kZXZAbGlzdHMub3psYWJzLm9yZwpodHRwczovL2xpc3RzLm96bGFi cy5vcmcvbGlzdGluZm8vbGludXhwcGMtZGV2 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 6ADD71A2A7C for ; Tue, 24 Nov 2015 00:57:38 +1100 (AEDT) Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 23 Nov 2015 13:57:34 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 870BC1B0806E for ; Mon, 23 Nov 2015 13:57:43 +0000 (GMT) Received: from d06av05.portsmouth.uk.ibm.com (d06av05.portsmouth.uk.ibm.com [9.149.37.229]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id tANDvLFj8651010 for ; Mon, 23 Nov 2015 13:57:21 GMT Received: from d06av05.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av05.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id tANDvKWP009109 for ; Mon, 23 Nov 2015 06:57:21 -0700 Subject: Re: kernel BUG at drivers/scsi/scsi_lib.c:1096! To: Mark Salter , 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> <565055C6.5040801@linux.vnet.ibm.com> <20151122005635.1b9ffbe1@tom-T450> <1448234410.8209.3.camel@redhat.com> Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, "James E. J. Bottomley" , linux-kernel@vger.kernel.org, Christoph Hellwig , brking , tom.leiming@gmail.com, linuxppc-dev@lists.ozlabs.org From: Laurent Dufour Message-ID: <56531B3F.60503@linux.vnet.ibm.com> Date: Mon, 23 Nov 2015 14:57:19 +0100 MIME-Version: 1.0 In-Reply-To: <1448234410.8209.3.camel@redhat.com> 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 23/11/2015 00:20, Mark Salter wrote: > On Sun, 2015-11-22 at 00:56 +0800, Ming Lei wrote: >> On Sat, 21 Nov 2015 12:30:14 +0100 >> Laurent Dufour wrote: >> >>> 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 ? >> >> Laurent, looks there is one bug in blk_bio_segment_split(), would you >> mind testing the following patch to see if it fixes your issue? >> >> --- >> From 6fc701231dcc000bc8bc4b9105583380d9aa31f4 Mon Sep 17 00:00:00 2001 >> From: Ming Lei >> Date: Sun, 22 Nov 2015 00:47:13 +0800 >> Subject: [PATCH] block: fix segment split >> >> Inside blk_bio_segment_split(), previous bvec pointer('bvprvp') >> always points to the iterator local variable, which is obviously >> wrong, so fix it by pointing to the local variable of 'bvprv'. >> >> Signed-off-by: Ming Lei >> --- >> block/blk-merge.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/block/blk-merge.c b/block/blk-merge.c >> index de5716d8..f2efe8a 100644 >> --- a/block/blk-merge.c >> +++ b/block/blk-merge.c >> @@ -98,7 +98,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, >> >> seg_size += bv.bv_len; >> bvprv = bv; >> - bvprvp = &bv; >> + bvprvp = &bvprv; >> sectors += bv.bv_len >> 9; >> continue; >> } >> @@ -108,7 +108,7 @@ new_segment: >> >> nsegs++; >> bvprv = bv; >> - bvprvp = &bv; >> + bvprvp = &bvprv; >> seg_size = bv.bv_len; >> sectors += bv.bv_len >> 9; >> } > > I'm still hitting the BUG even with this patch applied on top of 4.4-rc1. On my side, with the patch applied on top of 4.4-rc1, I can't get the panic anymore.