From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kent Overstreet <koverstreet@google.com>
Subject: Re: NULL pointer due to malformed bcache bio
Date: Mon, 22 Apr 2013 14:22:18 -0700
Message-ID: <20130422212218.GA4704@localhost>
References: <20130410205439.GA18092@redhat.com>
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To: Mike Snitzer <snitzer@redhat.com>
Cc: linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com, axboe@kernel.dk
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On Wed, Apr 10, 2013 at 04:54:40PM -0400, Mike Snitzer wrote:
> Hey,
> 
> So DM core clearly needs to be more defensive about the possibility for
> a NULL return from bio_alloc_bioset() given I'm hitting a NULL pointer
> in DM's alloc_tio() because nr_iovecs=512.  bio_alloc_bioset()'s call to
> bvec_alloc() only supports nr_iovecs up to BIO_MAX_PAGES (256).

I have a fix for this queued up in my bcache-for-upstream, if you want
to check and make sure it works.