From: Stanislav Meduna <stano@meduna.org>
To: "linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>
Cc: rostedt@goodmis.org, Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>
Subject: Re: timerfd read does not return - caused by MM fault
Date: Mon, 13 May 2013 10:05:02 +0200 [thread overview]
Message-ID: <51909EAE.8070901@meduna.org> (raw)
In-Reply-To: <519023C0.2030603@meduna.org>
On 13.05.2013 01:20, Stanislav Meduna wrote:
> So it looks like the problem happens inside the put_user,
> maybe a pagefault? The buf is an address on the stack:
Yep, this is a page fault. I added tracing of the
mm_fault_error
handle_mm_fault
handle_pte_fault
do_page_fault
functions
The result is
0....0 62811.755379: bprint: timerfd_read: timerfd_read after unlock, res=0
0d...0 62811.755382: function: do_page_fault
0....0 62811.755386: function: handle_mm_fault
0....0 62811.755389: function: handle_pte_fault
0d...0 62811.755394: function: do_page_fault
0....0 62811.755396: function: handle_mm_fault
0....0 62811.755398: function: handle_pte_fault
0d...0 62811.755402: function: do_page_fault
0....0 62811.755404: function: handle_mm_fault
0....0 62811.755406: function: handle_pte_fault
> Viewing the ps -o min_flt,maj_flt for the task shows 969701
> minor faults (that do not increment - I will check this when
> the hang happens again) and 0 major ones.
The number of minor faults of the thread jumped to 1433400 and
the process recovered after 2.77 seconds.
The trace file is at
http://www.meduna.org/tmp/trace.mmfaulthang.dat.gz
Thanks
--
Stano
next prev parent reply other threads:[~2013-05-13 8:05 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-15 11:02 hrtimer: interrupt took 6742 ns, then RT throttling and hung machine for nearly 2 seconds Stanislav Meduna
2013-04-15 11:54 ` Stanislav Meduna
2013-04-15 12:22 ` Thomas Gleixner
2013-04-15 12:56 ` Stanislav Meduna
2013-04-17 15:46 ` timerfd and softirqd [Was: Re: hrtimer: interrupt took 6742 ns, then RT throttling and hung machine for nearly 2 seconds] Stanislav Meduna
2013-04-18 9:11 ` timerfd read does not return [Was: Re: timerfd and softirqd] Stanislav Meduna
2013-04-19 19:53 ` Stanislav Meduna
2013-04-22 7:35 ` [PATCH] Re: timerfd read does not return Stanislav Meduna
2013-04-22 8:55 ` Stanislav Meduna
2013-04-27 8:34 ` timerfd read does not return - was probably fixed in 3.4.38 Stanislav Meduna
2013-04-28 11:53 ` Carsten Emde
2013-04-29 8:43 ` Stanislav Meduna
2013-05-02 20:02 ` Steven Rostedt
2013-05-10 12:42 ` timerfd read does not return - some traces Stanislav Meduna
2013-05-12 17:31 ` Stanislav Meduna
2013-05-12 23:20 ` timerfd read does not return - hangs inside put_user Stanislav Meduna
2013-05-13 8:05 ` Stanislav Meduna [this message]
2013-05-14 8:31 ` Livelock in handle_pte_fault [Was: Re: timerfd read does not return] Stanislav Meduna
2013-11-25 10:36 ` Vijay Katoch
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