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Date: Wed, 13 Mar 2024 11:06:46 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	Adrian Hunter <adrian.hunter@intel.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Ian Rogers <irogers@google.com>, Ingo Molnar <mingo@redhat.com>,
	Jiri Olsa <jolsa@kernel.org>, Marco Elver <elver@google.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2 0/4] perf: Make SIGTRAP and __perf_pending_irq() work
 on RT.
Message-ID: <ZfGy9ggOIvtr_-cd@x1>
References: <20240312180814.3373778-1-bigeasy@linutronix.de>
 <ZfDMTlTH2SdwlB9M@x1>
 <20240313081303.DClwQrvb@linutronix.de>
 <ZfGqCWzyVzyGQrAQ@x1>
 <20240313134645.bO-XyxAM@linutronix.de>
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In-Reply-To: <20240313134645.bO-XyxAM@linutronix.de>

On Wed, Mar 13, 2024 at 02:46:45PM +0100, Sebastian Andrzej Siewior wrote:
> On 2024-03-13 10:28:41 [-0300], Arnaldo Carvalho de Melo wrote:
> > > One part I don't get: did you let it run or did you kill it?
> > 
> > If I let them run they will finish and exit, no exec_child remains.
> > 
> > If I instead try to stop the loop that goes on forking the 100 of them,
> > then the exec_child remain spinning.
> 
> Okay. So that problem only exists if you intervene. And you can
> reproduce this odd behaviour with my patches but not without them,
> right?

See the next message, I managed to reproduce that behaviour in a non-RT
kernel as well.
 
- Arnaldo