diff options
| author | Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> | 2014-01-21 16:59:59 +0530 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2014-01-21 20:22:40 -0800 |
| commit | 9967d8ac5c0f3e730a21abefe4c889c724f3b212 (patch) | |
| tree | 0eb48ed7aa3c5f5b374545c814a402392d3c6a1e | |
| parent | 26d580575b4b8c3c83137315c9a2a77e60a2f716 (diff) | |
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>
| -rw-r--r-- | drivers/block/null_blk.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index a2e69d26266d..a01d7f68fc77 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -622,6 +622,11 @@ static int __init null_init(void) irqmode = NULL_IRQ_NONE; } #endif + if (bs > PAGE_SIZE) { + pr_warn("null_blk: invalid block size\n"); + pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE); + bs = PAGE_SIZE; + } if (queue_mode == NULL_Q_MQ && use_per_node_hctx) { if (submit_queues < nr_online_nodes) { |