[Skiboot] [PATCH] Limit number of "Poller recursion detected" errors to display

[Vasant Hegde]

On 11/16/2016 10:34 AM, Stewart Smith wrote:
> In some error conditions, we could spiral out of control on this
> and spend all of our time printing the exact same backtrace.
>
> Limit it to 16 times, because 16 is a nice number.
>
> Cc: stable
> Signed-off-by: Stewart Smith <stewart at linux.vnet.ibm.com>

Looks good.

Reviewed-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>


> ---
>   core/opal.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/core/opal.c b/core/opal.c
> index 61a2adb10602..269ab80df958 100644
> --- a/core/opal.c
> +++ b/core/opal.c
> @@ -313,9 +313,10 @@ void opal_run_pollers(void)
>   {
>   	struct opal_poll_entry *poll_ent;
>   	static int pollers_with_lock_warnings = 0;
> +	static int poller_recursion = 0;
>
>   	/* Don't re-enter on this CPU */
> -	if (this_cpu()->in_poller) {
> +	if (this_cpu()->in_poller && poller_recursion < 16) {
>   		/**
>   		 * @fwts-label OPALPollerRecursion
>   		 * @fwts-advice Recursion detected in opal_run_pollers(). This
> @@ -324,6 +325,9 @@ void opal_run_pollers(void)
>   		 */
>   		prlog(PR_ERR, "OPAL: Poller recursion detected.\n");
>   		backtrace();
> +		poller_recursion++;
> +		if (poller_recursion == 16)
> +			prlog(PR_ERR, "OPAL: Squashing future poller recursion warnings (>16).\n");
>   		return;
>   	}
>   	this_cpu()->in_poller = true;
>