Re: sched: serial port lockdep warning when offlining CPUs

[Peter Zijlstra]

On Thu, Sep 28, 2017 at 07:30:32PM +0900, Sergey Senozhatsky wrote:
> ---
> 
>  lib/ratelimit.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/ratelimit.c b/lib/ratelimit.c
> index 08f8043cac61..bddc55834c2e 100644
> --- a/lib/ratelimit.c
> +++ b/lib/ratelimit.c
> @@ -48,7 +48,8 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
>  	if (time_is_before_jiffies(rs->begin + rs->interval)) {
>  		if (rs->missed) {
>  			if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE)) {
> -				pr_warn("%s: %d callbacks suppressed\n", func, rs->missed);
> +				printk_deferred(KERN_WARN "%s: %d callbacks suppressed\n",
> +						func, rs->missed);
>  				rs->missed = 0;
>  			}
>  		}

Oh cute; I figured it was the syslog daemon suppressing multiple
identical lines, but yes the above looks very plausible.