Re: [PATCH] scsi: target: tcmu: Fix divide-by-zero in data_pages_per_blk store

[Bodo Strößer]

On 26/10/2026 12:52, shao.mingyin@xxxxxxxxxx wrote:

> From: Shao Mingyin <shao.mingyin@xxxxxxxxxx>
>
> tcmu_set_data_pages_per_blk() only validates the upper bound of the value
> parsed from data_pages_per_blk=. Zero passes that check and is then used
> as the divisor when computing udev->max_blocks:
>
>    divide error: 0000 [#1] SMP
>    ...
>    tcmu_set_data_pages_per_blk
>    tcmu_configure_device
>
> Reject non-positive values, as the neighbouring max_data_area_mb and
> cmd_ring_size setters already do.
>
> Fixes: 08976cb548d6 ("scsi: target: tcmu: Make data_pages_per_blk changeable via configfs")
> Signed-off-by: Shao Mingyin <shao.mingyin@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
> index 425ad1246a75..07b514678176 100644
> --- a/drivers/target/target_core_user.c
> +++ b/drivers/target/target_core_user.c
> @@ -2524,6 +2524,11 @@ static int tcmu_set_data_pages_per_blk(struct tcmu_dev *udev, substring_t *arg)
>   		return ret;
>   	}
>
> +	if (val <= 0) {
> +		pr_err("Invalid data_pages_per_blk %d.\n", val);
> +		return -EINVAL;
> +	}
> +
>   	if (val > TCMU_MBS_TO_PAGES(udev->data_area_mb)) {
>   		pr_err("Invalid data_pages_per_blk %d: greater than max_data_area_mb %d -> %zd pages).\n",
>   		       val, udev->data_area_mb,

Reviewed-by: Bodo Stroesser <bostroesser@xxxxxxxxx>

Thank you.

Regards,
Bodo Stroesser