Re: [PATCH] md/raid0: use kvzalloc/kvfree for strip_zone and devlist allocations

[Li Nan]

在 2026/3/9 7:42, Gregory Price 写道:
> syzbot reported a WARNING at mm/page_alloc.c:__alloc_frozen_pages_noprof()
> triggered by create_strip_zones() in the RAID0 driver.
>
> When raid_disks is large, the allocation size exceeds MAX_PAGE_ORDER (4MB
> on x86), causing WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER).
>
> Convert the strip_zone and devlist allocations from kzalloc/kzalloc_objs to
> kvzalloc/kvzalloc_objs, which first attempts a contiguous allocation with
> __GFP_NOWARN and then falls back to vmalloc for large sizes. Convert the
> corresponding kfree calls to kvfree.
>
> Both arrays are pure metadata lookup tables (arrays of pointers and zone
> descriptors) accessed only via indexing, so they do not require physically
> contiguous memory.
>
> Reported-by: syzbot+924649752adf0d3ac9dd@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Gregory Price <gourry@xxxxxxxxxx>
> ---
>   drivers/md/raid0.c | 18 +++++++++---------
>   1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index ef0045db409f..5e38a51e349a 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -143,13 +143,13 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
>   	}
>   
>   	err = -ENOMEM;
> -	conf->strip_zone = kzalloc_objs(struct strip_zone, conf->nr_strip_zones);
> +	conf->strip_zone = kvzalloc_objs(struct strip_zone, conf->nr_strip_zones);
>   	if (!conf->strip_zone)
>   		goto abort;
> -	conf->devlist = kzalloc(array3_size(sizeof(struct md_rdev *),
> -					    conf->nr_strip_zones,
> -					    mddev->raid_disks),
> -				GFP_KERNEL);
> +	conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
> +					     conf->nr_strip_zones,
> +					     mddev->raid_disks),
> +				 GFP_KERNEL);
>   	if (!conf->devlist)
>   		goto abort;
>   
> @@ -291,8 +291,8 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
>   
>   	return 0;
>   abort:
> -	kfree(conf->strip_zone);
> -	kfree(conf->devlist);
> +	kvfree(conf->strip_zone);
> +	kvfree(conf->devlist);
>   	kfree(conf);
>   	*private_conf = ERR_PTR(err);
>   	return err;
> @@ -373,8 +373,8 @@ static void raid0_free(struct mddev *mddev, void *priv)
>   {
>   	struct r0conf *conf = priv;
>   
> -	kfree(conf->strip_zone);
> -	kfree(conf->devlist);
> +	kvfree(conf->strip_zone);
> +	kvfree(conf->devlist);
>   	kfree(conf);
>   }
>   


LGTM

Reviewed-by: Li Nan <linan122@xxxxxxxxxx>

--
Thanks,
Nan