Re: [PATCH] md/raid0: fix NULL pointer dereference in create_strip_zones() for dm-raid

[Paul Menzel]

Dear Kuai,


Thank you for your patch.

Am 16.11.25 um 03:18 schrieb Yu Kuai:
> Commit 2107457e31fa ("md/raid0: Move queue limit setup before r0conf
> initialization") dereference mddev->gendisk unconditionally, which is
> NULL for dm-raid.
>
> Fix this problem by reverting to old codes for dm-raid.
>
> Fixes: 2107457e31fa ("md/raid0: Move queue limit setup before r0conf initialization")
> Reported-and-tested-by: Changhui Zhong <czhong@xxxxxxxxxx>
> Closes: https://lore.kernel.org/all/CAGVVp+VqVnvGeneUoTbYvBv2cw6GwQRrR3B-iQ-_9rVfyumoKA@xxxxxxxxxxxxxx/
> Signed-off-by: Yu Kuai <yukuai@xxxxxxxxx>
> ---
>   drivers/md/raid0.c | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index 47aee1b1d4d1..985c377356eb 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -68,7 +68,10 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
>   	struct strip_zone *zone;
>   	int cnt;
>   	struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
> -	unsigned int blksize = queue_logical_block_size(mddev->gendisk->queue);
> +	unsigned int blksize = 512;
> +
> +	if (!mddev_is_dm(mddev))
> +		blksize = queue_logical_block_size(mddev->gendisk->queue);
>   
>   	*private_conf = ERR_PTR(-ENOMEM);
>   	if (!conf)
> @@ -84,6 +87,10 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
>   		sector_div(sectors, mddev->chunk_sectors);
>   		rdev1->sectors = sectors * mddev->chunk_sectors;
>   
> +		if (mddev_is_dm(mddev))
> +			blksize = max(blksize, queue_logical_block_size(
> +				      rdev1->bdev->bd_disk->queue));
> +
>   		rdev_for_each(rdev2, mddev) {
>   			pr_debug("md/raid0:%s:   comparing %pg(%llu)"
>   				 " with %pg(%llu)\n",

Reviewed-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>


Kind regards,

Paul