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From: Robert Stupp <snazy@gmx.de>
To: Michal Hocko <mhocko@kernel.org>, snazy@snazy.de
Cc: Randy Dunlap <rdunlap@infradead.org>,
	linux-kernel@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Potyra, Stefan" <Stefan.Potyra@elektrobit.com>
Subject: Re: mlockall(MCL_CURRENT) blocking infinitely
Date: Fri, 25 Oct 2019 13:59:59 +0200	[thread overview]
Message-ID: <eab6798a6081fba94353be71681fcd8c7dcf8011.camel@gmx.de> (raw)
In-Reply-To: <20191025115038.GF17610@dhcp22.suse.cz>

On Fri, 2019-10-25 at 13:50 +0200, Michal Hocko wrote:
> On Fri 25-10-19 13:46:33, Michal Hocko wrote:
> > On Fri 25-10-19 13:02:23, Robert Stupp wrote:
> > > On Fri, 2019-10-25 at 11:21 +0200, Michal Hocko wrote:
> > > > On Thu 24-10-19 16:34:46, Randy Dunlap wrote:
> > > > > [adding linux-mm + people]
> > > > >
> > > > > On 10/24/19 12:36 AM, Robert Stupp wrote:
> > > > > > Hi guys,
> > > > > >
> > > > > > I've got an issue with `mlockall(MCL_CURRENT)` after
> > > > > > upgrading
> > > > > > Ubuntu 19.04 to 19.10 - i.e. kernel version change from
> > > > > > 5.0.x to
> > > > > > 5.3.x.
> > > > > >
> > > > > > The following simple program hangs forever with one CPU
> > > > > > running
> > > > > > at 100% (kernel):
> > > >
> > > > Can you capture everal snapshots of proc/$(pidof
> > > > $YOURTASK)/stack
> > > > while
> > > > this is happening?
>
> Btw. I have tested
> $ cat test_mlockall.c
> #include <stdio.h>
> #include <sys/mman.h>
> int main(char** argv) {
> 	printf("Before mlockall(MCL_CURRENT|MCL_FUTURE)\n");
> 	// works in 5.0
> 	// hangs forever w/ 5.1 and newer
> 	int e = mlockall(MCL_CURRENT|MCL_FUTURE);
> 	printf("After mlockall(MCL_CURRENT|MCL_FUTURE) %d\n", e);
> }
>
> $./test_mlockall
> Before mlockall(MCL_CURRENT|MCL_FUTURE)
> After mlockall(MCL_CURRENT|MCL_FUTURE) 0

I suspect, that it's something that's "special" on my machine. But I've
got no clue what that might be. Do you think it makes sense to try with
all the spectre/meltdown mitigations disabled? Or SMT disabled?


  reply	other threads:[~2019-10-25 12:00 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-24  7:36 mlockall(MCL_CURRENT) blocking infinitely Robert Stupp
2019-10-24 23:34 ` Randy Dunlap
2019-10-25  9:21   ` Michal Hocko
2019-10-25 11:02     ` Robert Stupp
2019-10-25 11:46       ` Michal Hocko
2019-10-25 11:50         ` Michal Hocko
2019-10-25 11:59           ` Robert Stupp [this message]
2019-10-25 13:19             ` Robert Stupp
2019-10-25 11:55         ` Robert Stupp
2019-10-25 12:05           ` Michal Hocko
2019-10-25 12:11             ` Michal Hocko
2019-10-25 13:10               ` Robert Stupp
2019-10-25 13:27                 ` Michal Hocko
2019-10-25 13:45                   ` Robert Stupp
2019-10-25 13:57                     ` Michal Hocko
2019-10-25 14:00                       ` Michal Hocko
2019-10-25 15:58                         ` Robert Stupp
2019-11-05 13:23                           ` Robert Stupp
2019-11-05 15:28                             ` Vlastimil Babka
2019-11-05 18:22                               ` Johannes Weiner
2019-11-05 20:05                                 ` Robert Stupp
2019-11-06 10:25                                   ` Robert Stupp
2019-11-06 11:26                                     ` Robert Stupp
2019-11-06 12:04                                       ` Jan Kara
2019-11-06 12:24                                       ` Robert Stupp
2019-11-06 12:03                                 ` Jan Kara
2019-11-06 13:45                                   ` Robert Stupp
2019-11-06 14:35                                     ` Jan Kara
2019-11-06 15:32                                       ` Robert Stupp
2019-11-06 14:38                                     ` Jan Kara
2019-11-06 14:56                                     ` Josef Bacik
2019-11-06 15:05                                       ` Jan Kara
2019-11-06 15:14                                         ` Josef Bacik
2019-11-06 15:25                                           ` Jan Kara
2019-11-06 16:39                                           ` Robert Stupp
2019-11-06 17:03                                             ` Robert Stupp
2019-11-06 17:25                                               ` Jan Kara
2019-11-07  8:08                                                 ` Robert Stupp
2019-11-20 12:42                                                   ` Robert Stupp
2019-10-25 13:55                   ` Robert Stupp

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