From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jens Axboe <axboe@kernel.dk>
Subject: Re: [RFC PATCH V3 1/2]  null_blk: Null pointer deference problem in
 alloc_page_buffers
Date: Tue, 21 Jan 2014 20:22:09 -0800
Message-ID: <20140122042209.GF20347@kernel.dk>
References: <1390303800-22422-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com>
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Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	Matias Bjorling <m@bjorling.me>,
	Andrew Morton <akpm@linux-foundation.org>,
	Yuanhan Liu <yuanhan.liu@linux.intel.com>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Jan Kara <jack@suse.cz>, Johannes Weiner <hannes@cmpxchg.org>,
	Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
	Jeff <jmoyer@redhat.com>, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Sumanth <sumantk2@linux.vnet.ibm.com>
To: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
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On Tue, Jan 21 2014, Raghavendra K T wrote:
>  If we load the null_blk module with bs=8k we get following oops:
> [ 3819.812190] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> [ 3819.812387] IP: [<ffffffff81170aa5>] create_empty_buffers+0x28/0xaf
> [ 3819.812527] PGD 219244067 PUD 215a06067 PMD 0
> [ 3819.812640] Oops: 0000 [#1] SMP
> [ 3819.812772] Modules linked in: null_blk(+)
> 
>  Fix that by resetting block size to PAGE_SIZE if it is greater than PAGE_SIZE

Thanks, applied.

-- 
Jens Axboe