linux-kernel - Re: [PATCH,RFC] perf: panic due to inclied cpu context task

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 26 Mar 2011 18:09:22 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	Jiri Olsa <jolsa@...hat.com>, Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH,RFC] perf: panic due to inclied cpu context task_ctx
	value

On 03/26, Peter Zijlstra wrote:
>
> diff --git a/kernel/perf_event.c b/kernel/perf_event.c
> index c75925c..e9e4e35 100644
> --- a/kernel/perf_event.c
> +++ b/kernel/perf_event.c
> @@ -1073,6 +1073,8 @@ event_sched_out(struct perf_event *event,
>  	if (!is_software_event(event))
>  		cpuctx->active_oncpu--;
>  	ctx->nr_active--;
> +	if (!ctx->nr_active && cpuctx->task_ctx == ctx)
> +		cpuctx->task_ctx = NULL;

If we clear cpuctx->task_ctx, we should also clear ctx->is_active.

Otherwise I can't see any problem, but I do not understand this code
enough.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/