Re: [PATCH] md: protect read mddev->recovery in md_sync_action()

On Sat, Jun 27, 2026 at 18:29 +0800, Chen Cheng wrote:
> From: Chen Cheng <[email protected]>
>
> md_sync_action() read mddev->recovery in lockless path, use READ_ONCE()
> instead of u64 plain read.
>
unisgned long is not always u64...
I can not see what it fixes, is this just to silence KCSAN? If so,
please say so in the commit message.

> Fixes: e792a4c2156a3 ("md: add new helpers for sync_action")
>
> Signed-off-by: Chen Cheng <[email protected]>
> ---
>  drivers/md/md.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index c5c50640b684..f4415c1a79d9 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -5074,11 +5074,11 @@ static enum sync_action md_get_active_sync_action(struct mddev *mddev)
>  	return is_recover ? ACTION_RECOVER : ACTION_IDLE;
>  }
>  
>  enum sync_action md_sync_action(struct mddev *mddev)
>  {
> -	unsigned long recovery = mddev->recovery;
> +	unsigned long recovery = READ_ONCE(mddev->recovery);
>  	enum sync_action active_action;
>  
>  	/*
>  	 * frozen has the highest priority, means running sync_thread will be
>  	 * stopped immediately, and no new sync_thread can start.
> -- 
> 2.54.0
>

-- 
Best Regards,
Abd-Alrhman