From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751667AbeDIXez (ORCPT ); Mon, 9 Apr 2018 19:34:55 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:35906 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750759AbeDIXex (ORCPT ); Mon, 9 Apr 2018 19:34:53 -0400 Date: Tue, 10 Apr 2018 07:34:37 +0800 From: Ming Lei To: Bart Van Assche Cc: "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "richard.weinberger@gmail.com" , "linux-block@vger.kernel.org" , "wakko@animx.eu.org" Subject: Re: 4.15.14 crash with iscsi target and dvd Message-ID: <20180409233436.GC6450@ming.t460p> References: <20180401163604.GB25011@animx.eu.org> <20180401182723.GA31755@animx.eu.org> <595a10cfb387e6b2ab4d2053b84fed9b3da9e079.camel@wdc.com> <20180406014644.GA16112@animx.eu.org> <20180406020651.GB16112@animx.eu.org> <20180407165335.GA2515@animx.eu.org> <1ff8d234cc565ba9701ce31899fca5faa597e050.camel@wdc.com> <20180408160254.GA22869@animx.eu.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 09, 2018 at 09:30:11PM +0000, Bart Van Assche wrote: > On Sun, 2018-04-08 at 12:02 -0400, Wakko Warner wrote: > > I finished with git bisect. Here's the output: > > 84c8590646d5b35804bac60eb58b145839b5893e is the first bad commit > > commit 84c8590646d5b35804bac60eb58b145839b5893e > > Author: Ming Lei > > Date: Fri Nov 11 20:05:32 2016 +0800 > > > > target: avoid accessing .bi_vcnt directly > > > > When the bio is full, bio_add_pc_page() will return zero, > > so use this information tell when the bio is full. > > > > Also replace access to .bi_vcnt for pr_debug() with bio_segments(). > > > > Reviewed-by: Christoph Hellwig > > Signed-off-by: Ming Lei > > Reviewed-by: Sagi Grimberg > > Signed-off-by: Jens Axboe > > > > :040000 040000 a3ebbb71c52ee4eb8c3be4d033b81179211bf704 de39a328dbd1b18519946b3ad46d9302886e0dd0 M drivers > > > > I did a diff between HEAD^ and HEAD and manually patched the file from > > 4.15.14. It's not an exact revert. I'm running it now and it's working. > > I'll do a better test later on. Here's the patch: > > > > --- a/drivers/target/target_core_pscsi.c 2018-02-04 14:31:31.077316617 -0500 > > +++ b/drivers/target/target_core_pscsi.c 2018-04-08 11:43:49.588641374 -0400 > > @@ -915,7 +915,9 @@ > > bio, page, bytes, off); > > pr_debug("PSCSI: bio->bi_vcnt: %d nr_vecs: %d\n", > > bio_segments(bio), nr_vecs); > > - if (rc != bytes) { > > + if (rc != bytes) > > + goto fail; > > + if (bio->bi_vcnt > nr_vecs) { > > pr_debug("PSCSI: Reached bio->bi_vcnt max:" > > " %d i: %d bio: %p, allocating another" > > " bio\n", bio->bi_vcnt, i, bio); > > Hello Ming, > > Can you have a look at this? The start of this e-mail thread is available at > https://www.mail-archive.com/linux-scsi@vger.kernel.org/msg72574.html. Sure, thanks for your sharing. Wakko, could you test the following patch and see if there is any difference? -- diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c index 0d99b242e82e..6147178f1f37 100644 --- a/drivers/target/target_core_pscsi.c +++ b/drivers/target/target_core_pscsi.c @@ -888,7 +888,7 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents, if (len > 0 && data_len > 0) { bytes = min_t(unsigned int, len, PAGE_SIZE - off); bytes = min(bytes, data_len); - + new_bio: if (!bio) { nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages); nr_pages -= nr_vecs; @@ -931,6 +931,7 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents, * be allocated with pscsi_get_bio() above. */ bio = NULL; + goto new_bio; } data_len -= bytes; -- Ming