Date: Wed, 29 Feb 2012 14:31:39 -0500 From: Arnaud Lacombe <lacombar@gmail.com> To: Attilio Rao <attilio@freebsd.org> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: Complete hang on 9.0-RELEASE Message-ID: <CACqU3MVBzkg%2BjzkBNjcXRqTfxZEX0rXs3HwjQN=hLSfSZWGn7g@mail.gmail.com> In-Reply-To: <CAJ-FndBW2=78cEWfvYFDjZ3z_VOs-Gj836eo7pgwmy0UmuaCeA@mail.gmail.com> References: <CACqU3MUefo4mG3GdZnj6kxxFx4H_M3-NLys8pCKptqNU4r_ywA@mail.gmail.com> <CACqU3MVs1mpiQpjE9xC8aFAKxhzbjUgC_6GKWdAkyr8OGJhycw@mail.gmail.com> <CAJ-FndDz6eRamnf7v6kZwwZQp-JaLYUKX6Gx7MYuZGEFNagmfQ@mail.gmail.com> <CACqU3MV-mDHzmnXY3Mzc%2BBnimJSnUTAPk66fh%2Bzzdfgz4OyPFg@mail.gmail.com> <CACqU3MVL14TxJ81rbM-Oq2P8GZCE0hPKzQpb5eJqZ32YdowSjQ@mail.gmail.com> <CACqU3MVko6jKjs98JeS1NqBp%2BFR0YtMqPq570J3dN7BPyFvdkA@mail.gmail.com> <CAJ-FndCtA6F=XzTbYsDD1y3-aXuOSMDobtSuOgdNVwaNU4kY_A@mail.gmail.com> <CACqU3MWdJAp2XqWESUTtvX7CeESm=WEcqcRa0T105Kx95jMXzA@mail.gmail.com> <CAJ-FndBW2=78cEWfvYFDjZ3z_VOs-Gj836eo7pgwmy0UmuaCeA@mail.gmail.com>
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Hi, On Wed, Feb 29, 2012 at 2:22 PM, Attilio Rao <attilio@freebsd.org> wrote: > 2012/2/29, Arnaud Lacombe <lacombar@gmail.com>: >> Hi, >> >> On Wed, Feb 29, 2012 at 1:44 PM, Attilio Rao <attilio@freebsd.org> wrote= : >>> 2012/2/29, Arnaud Lacombe <lacombar@gmail.com>: >>>> Hi, >>>> >>>> On Wed, Feb 29, 2012 at 12:59 PM, Arnaud Lacombe <lacombar@gmail.com> >>>> wrote: >>>>> Hi, >>>>> >>>>> On Mon, Feb 27, 2012 at 12:48 PM, Arnaud Lacombe <lacombar@gmail.com> >>>>> wrote: >>>>>> Hi, >>>>>> >>>>>> On Mon, Feb 27, 2012 at 10:36 AM, Attilio Rao <attilio@freebsd.org> >>>>>> wrote: >>>>>>> 2012/2/27, Arnaud Lacombe <lacombar@gmail.com>: >>>>>>>> Hi, >>>>>>>> >>>>>>>> On Tue, Feb 14, 2012 at 11:41 AM, Arnaud Lacombe <lacombar@gmail.c= om> >>>>>>>> wrote: >>>>>>>>> Hi folks, >>>>>>>>> >>>>>>>>> For the records, I was running some tests yesterday on top of a >>>>>>>>> 9.0-RELEASE, amd64, kernel when the box hanged. At the time of th= e >>>>>>>>> hang, the box was running a process with about 2800 threads with >>>>>>>>> heavy >>>>>>>>> IPC between 1400 writers and 1400 readers. The box was in single >>>>>>>>> user >>>>>>>>> mode (/bin/sh coming from FreeBSD 7.4-STABLE). Here is the beginn= ing >>>>>>>>> of the dmesg: >>>>>>>>> >>>>>>>> This happened a second time, now with FreeBSD 8.2-RELEASE. Complet= e >>>>>>>> machine hang. The machine was running about 4000 threads in a sing= le >>>>>>>> process, all the other condition are the same. >>>>>>> >>>>>>> Arnaud, >>>>>>> can you please break in your kernel via KDB, collect the following >>>>>>> informations from the DDB prompt: >>>>>>> - ps >>>>>>> - alltrace >>>>>>> - show allpcpu >>>>>>> - possibly get a coredump with 'call doadump' >>>>>>> >>>>>> Will do, but I'll need to rebuild a kernel to include DDB. >>>>>> >>>>>>> and in the end provide all those along with kernel binary and possi= bly >>>>>>> sources somewhere? >>>>>>> >>>>>> I'll be testing a bare `release/8.2.0' with the following patch: >>>>>> >>>>>> diff --git a/sys/amd64/conf/GENERIC b/sys/amd64/conf/GENERIC >>>>>> index c3e0095..7bd997f 100644 >>>>>> --- a/sys/amd64/conf/GENERIC >>>>>> +++ b/sys/amd64/conf/GENERIC >>>>>> @@ -79,6 +79,10 @@ options =A0 =A0 =A0INCLUDE_CONFIG_FILE =A0 =A0 # = Include this >>>>>> file in kernel >>>>>> >>>>>> =A0options =A0 =A0 =A0 =A0KDB =A0 =A0 =A0 =A0 =A0 # Kernel debugger = related code >>>>>> =A0options =A0 =A0 =A0 =A0KDB_TRACE =A0 =A0 # Print a stack trace fo= r a panic >>>>>> +options =A0 =A0 =A0 =A0DDB >>>>>> +options =A0 =A0 =A0 =A0BREAK_TO_DEBUGGER >>>>>> +options =A0 =A0 =A0 =A0ALT_BREAK_TO_DEBUGGER >>>>>> >>>>>> =A0# Make an SMP-capable kernel by default >>>>>> =A0options =A0 =A0 =A0 =A0SMP =A0 =A0 =A0 =A0 =A0 # Symmetric MultiP= rocessor Kernel >>>>>> >>>>> ok, it happened again after 2 days, the process was running about 320= 0 >>>>> threads. I'm trying to break into DDB and let you know, I'm not that >>>>> successful for now... >>>>> >>>> No luck. None of BREAK or ALT_BREAK are responding. I will not touch >>>> the system in the next few hours if you want me to test something on >>>> it. In the event of 8.2-RELEASE or 9.0-RELEASE are =A0not meant to wor= k >>>> reliably on top of a 7.4-RELEASE userland, I will re-setup the test to >>>> occurs on a clean 9.0-RELEASE system and re-try. >>> >>> We allow to break KBI when new releases happens, thus this may cause a >>> breakage for you, even if a deadlock is really not something you want. >>> >>> Can you try enabling SW_WATCHDOG, DEADLKRES and possibly arm your ichwd= ? >>> if the breakage involves clocks or interrupt sources there are still >>> chances they will be able to catch it though. >>> >>> However, it doesn't seem you are setup with a proper serial console? >> The serial console is working definitively fine. I can break into DDB >> at will when the test is running. I did not test with ALT_BREAK >> per-se, but BREAK does work. > > So if you try to break in DDB via serial break it doesn't work? > That is definitively very bad... > just to be sure, I rebooted the system and I could break into DDB at the first attempt with ALT_BREAK, BREAK was a bit more reluctant but worked too. So yes, this does not taste good :/ > Can you try with the options I mentioned earlier and see if something cha= nges? > will do, but I will first attempt to reproduce this on 9.0-RELEASE. - Arnaud > Attilio > > > -- > Peace can only be achieved by understanding - A. Einstein
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