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From: Christoph Hellwig <hch@lst.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Chinner <david@fromorbit.com>,
	Chris Leech <cleech@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Lee Duncan <lduncan@suse.com>,
	open-iscsi@googlegroups.com,
	Linux SCSI List <linux-scsi@vger.kernel.org>,
	linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [4.10, panic, regression] iscsi: null pointer deref at iscsi_tcp_segment_done+0x20d/0x2e0
Date: Thu, 22 Dec 2016 07:18:27 +0100	[thread overview]
Message-ID: <20161222061827.GA31630@lst.de> (raw)
In-Reply-To: <CA+55aFyb1jcdpavyZgZ4nedA0=6tLognyWcJXfOJjMPFTm5GWA@mail.gmail.com>

On Wed, Dec 21, 2016 at 03:19:15PM -0800, Linus Torvalds wrote:
> Looking around a bit, the only even halfway suspicious scatterlist
> initialization thing I see is commit f9d03f96b988 ("block: improve
> handling of the magic discard payload") which used to have a magic
> hack wrt !bio->bi_vcnt, and that got removed. See __blk_bios_map_sg(),
> now it does __blk_bvec_map_sg() instead.

But that check was only for discard (and discard-like) bios which
had the maic single page that sometimes was unused attached.

For "normal" bios the for_each_segment loop iterates over bi_vcnt,
so it will be ignored anyway.  That being said both I and the lists
got CCed halfway through the thread and I haven't seen the original
report, so I'm not really sure what's going on here anyway.

  parent reply	other threads:[~2016-12-22  6:18 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20161214222411.GH4326@dastard>
     [not found] ` <20161214222953.GI4326@dastard>
     [not found]   ` <20161216185906.t2wmrr6wqjdsrduw@straylight.hirudinean.org>
2016-12-21 22:16     ` [4.10, panic, regression] iscsi: null pointer deref at iscsi_tcp_segment_done+0x20d/0x2e0 Dave Chinner
2016-12-21 23:19       ` Linus Torvalds
2016-12-22  0:13         ` Chris Leech
2016-12-22  5:13           ` Dave Chinner
2016-12-22  5:46             ` Linus Torvalds
2016-12-22  6:50               ` Dave Chinner
2016-12-22 18:50                 ` Chris Leech
2016-12-22 23:53                   ` Ming Lei
2016-12-23  0:03                     ` Chris Leech
2016-12-23 10:00                       ` Christoph Hellwig
2016-12-23 19:42                         ` Linus Torvalds
2016-12-24  2:45                           ` Jens Axboe
2016-12-24  9:49                             ` Christoph Hellwig
2016-12-24 10:07                           ` Christoph Hellwig
2016-12-24 13:17                             ` Hannes Reinecke
2016-12-24 13:19                               ` Christoph Hellwig
2017-01-04 14:07                               ` Christoph Hellwig
2016-12-22 20:22               ` Hugh Dickins
2016-12-23  7:32                 ` Johannes Weiner
2016-12-23  8:33                   ` Johannes Weiner
2017-01-02 21:11                     ` Johannes Weiner
2017-01-03 12:28                       ` Jan Kara
2017-01-04 15:26                         ` Laurence Oberman
2017-01-04 17:38                           ` Laurence Oberman
2017-01-08  2:02                         ` Johannes Weiner
2017-01-08  2:17                           ` Linus Torvalds
2017-01-09 20:30                           ` Jan Kara
2017-01-09 20:45                             ` Johannes Weiner
2016-12-22  6:28             ` Dave Chinner
2016-12-22  6:18         ` Christoph Hellwig [this message]
2016-12-22  6:30           ` Dave Chinner
2016-12-22  6:36             ` Christoph Hellwig

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