[Crash-utility] [PATCH v2 1/1] CFS runqueue loop detection

[Dave Anderson]

----- Original Message -----
> Here is a patch against crash v6.0.3rc24 that adds duplicate node
> detection per-CPU for the CFS runqueue display in dump_CFS_runqueues()
> for the runq command.
> 
> This resolves for that 6.0.3 rc the failure to bail-out of the unending
> looping display I get with the crash dump I have that has a corrupted
> CFS runqueue containing a loop.
> 
> Signed-off-by: David Mair <dmair at suse.com>
> ---
>  task.c |   11 ++++++++++-
>  1 files changed, 10 insertions(+), 1 deletions(-)
> 
> diff --git a/task.c b/task.c
> index c81cb74..7a3e8e1 100755
> --- a/task.c
> +++ b/task.c
> @@ -7060,7 +7060,14 @@ dump_tasks_in_cfs_rq(ulong cfs_rq)
>  				     OFFSET(sched_entity_run_node));
>  		if (!tc)
>  			continue;
> -		dump_task_runq_entry(tc);
> +		if (hq_enter((ulong)tc)) {
> +			dump_task_runq_entry(tc);
> +		} else {
> +			error(WARNING, "Duplicate CFS runqueue node, task %lx"
> +				", probable loop\n",
> +				tc->task);
> +			return total;
> +		}
>  		total++;
>  	}
> 
> @@ -7220,7 +7227,9 @@ dump_CFS_runqueues(void)
> 
>  		fprintf(fp, "  CFS RB_ROOT: %lx\n", (ulong)root);
> 
> +		hq_open();
>  		tot = dump_tasks_in_cfs_rq(cfs_rq);
> +		hq_close();
>  		if (!tot) {
>  			INDENT(5);
>  			fprintf(fp, "[no tasks queued]\n");
> 

Thanks Dave -- queued for crash-6.0.3.

Dave