Re: [PATCH v2 1/5] md/md-bitmap: call md_bitmap_create,destroy in location_store

在 2026/4/7 18:26, Su Yue 写道:
> If bitmap/location is present, mdadm will call update_array_info()
> while growing bitmap from none to internal via location_store().
> md_bitmap_create() is needed to set mddev->bitmap_ops otherwise
> mddev->bitmap_ops->get_stats() in update_array_info() will trigger
> kernel NULL pointer dereference.
> 
> Fixes: fb8cc3b0d9db ("md/md-bitmap: delay registration of bitmap_ops until creating bitmap")
> Signed-off-by: Su Yue <[email protected]>
> ---
>   drivers/md/md-bitmap.c | 11 ++++++++---
>   drivers/md/md.c        |  4 ++--
>   drivers/md/md.h        |  2 ++
>   3 files changed, 12 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
> index 83378c033c72..2f24aae05552 100644
> --- a/drivers/md/md-bitmap.c
> +++ b/drivers/md/md-bitmap.c
> @@ -2618,7 +2618,7 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
>   			goto out;
>   		}
>   
> -		bitmap_destroy(mddev);
> +		md_bitmap_destroy(mddev);
>   		mddev->bitmap_info.offset = 0;
>   		if (mddev->bitmap_info.file) {
>   			struct file *f = mddev->bitmap_info.file;
> @@ -2653,15 +2653,20 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
>   				goto out;
>   			}
>   
> +			/*
> +			 * lockless bitmap shoudle have set bitmap_id
> +			 * using bitmap_type, so always ID_BITMAP.
> +			 */
> +			mddev->bitmap_id = ID_BITMAP;
>   			mddev->bitmap_info.offset = offset;
> -			rv = bitmap_create(mddev);
> +			rv = md_bitmap_create(mddev);
>   			if (rv)
>   				goto out;
>   
>   			rv = bitmap_load(mddev);

mddev->bitmap_ops->load() should also be used here.

-- 
Thanks,
Nan