From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sebastian Roesner <sroesner-kernelorg@roesner-online.de>
Subject: Re: [BUG] NULL pointer in raid1_make_request passed to bio_trim when
 adding md as bcache caching dev
Date: Sat, 26 Mar 2016 17:46:16 +0100
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To: Ming Lei <ming.lei@canonical.com>, Eric Wheeler <bcache@lists.ewheeler.net>
Cc: linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org, Ming Lin <mlin@kernel.org>, Vlad-Cosmin Miu <miuvlad@gmail.com>, rjones@redhat.com, Kent Overstreet <kent.overstreet@gmail.com>
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Hello Ming, Eric,

Am 26.03.2016 um 16:40 schrieb Ming Lei:
>  From the trace, looks the bio returned from bio_clone_mddev() is NULL,
> and maybe the source bio is buggy, something like the attached patch
> might be helpful, could you apply the attached debug patch, reproduce
> and post the log?

I was able to reproduce it on a non-productive system, but only after 
copying the bcache superblocks/partition starts from the original 
system, with new created ones it worked fine.

Full trace and check_bio output can be found here:

http://pastebin.com/ngvGGHBZ

Sebastian