From c462ecd659b5fce731f1d592285832fd6ad54053 Mon Sep 17 00:00:00 2001
From: Andreas Hindborg <a.hindborg@samsung.com>
Date: Mon, 3 Jun 2024 21:26:45 +0200
Subject: [PATCH] null_blk: fix validation of block size

Block size should be between 512 and PAGE_SIZE and be a power of 2. The current
check does not validate this, so update the check.

Without this patch, null_blk would Oops due to a null pointer deref when
loaded with bs=1536 [1].

Link: https://lore.kernel.org/all/87wmn8mocd.fsf@metaspace.dk/

Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20240603192645.977968-1-nmi@metaspace.dk
[axboe: remove unnecessary braces and != 0 check]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 drivers/block/null_blk/main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 631dca2e4e844..75f189e42f885 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1824,8 +1824,8 @@ static int null_validate_conf(struct nullb_device *dev)
 		dev->queue_mode = NULL_Q_MQ;
 	}
 
-	dev->blocksize = round_down(dev->blocksize, 512);
-	dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
+	if (blk_validate_block_size(dev->blocksize))
+		return -EINVAL;
 
 	if (dev->use_per_node_hctx) {
 		if (dev->submit_queues != nr_online_nodes)
-- 
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