From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Date: Tue, 21 Jan 2014 11:29:59 +0000 (+0530)
Subject: null_blk: Null pointer deference problem in alloc_page_buffers
X-Git-Tag: v3.14-rc1~42^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9967d8ac5c0f3e730a21abefe4c889c724f3b212;p=pandora-kernel.git

null_blk: Null pointer deference problem in alloc_page_buffers

 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

Reported-by: Sumanth <sumantk2@linux.vnet.ibm.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Reviewed-by: Matias Bjorling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

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