Date: Mon, 5 Mar 2012 18:50:27 +0000 From: Attilio Rao <attilio@freebsd.org> To: Arnaud Lacombe <lacombar@gmail.com> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: Complete hang on 9.0-RELEASE Message-ID: <CAJ-FndBYx3PtLF9nfy-HFywss5R-OcsNqCb9wZfcjUqEfD0W=g@mail.gmail.com> In-Reply-To: <CACqU3MXCf4U9OHShR1BwvPOsiP9=5=A4oTZR02qC8weKhU6p6g@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> <CACqU3MVBzkg%2BjzkBNjcXRqTfxZEX0rXs3HwjQN=hLSfSZWGn7g@mail.gmail.com> <CACqU3MXCf4U9OHShR1BwvPOsiP9=5=A4oTZR02qC8weKhU6p6g@mail.gmail.com>
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2012/3/5, Arnaud Lacombe <lacombar@gmail.com>: > Hi, > > On Wed, Feb 29, 2012 at 2:31 PM, Arnaud Lacombe <lacombar@gmail.com> wrote: >> 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.com> >>>>>>>>>> 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 >>>>>>>>>>> the >>>>>>>>>>> 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 >>>>>>>>>>> beginning >>>>>>>>>>> of the dmesg: >>>>>>>>>>> >>>>>>>>>> This happened a second time, now with FreeBSD 8.2-RELEASE. >>>>>>>>>> Complete >>>>>>>>>> machine hang. The machine was running about 4000 threads in a >>>>>>>>>> single >>>>>>>>>> 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 >>>>>>>>> possibly >>>>>>>>> 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 INCLUDE_CONFIG_FILE # Include >>>>>>>> this >>>>>>>> file in kernel >>>>>>>> >>>>>>>> options KDB # Kernel debugger related code >>>>>>>> options KDB_TRACE # Print a stack trace for a panic >>>>>>>> +options DDB >>>>>>>> +options BREAK_TO_DEBUGGER >>>>>>>> +options ALT_BREAK_TO_DEBUGGER >>>>>>>> >>>>>>>> # Make an SMP-capable kernel by default >>>>>>>> options SMP # Symmetric MultiProcessor Kernel >>>>>>>> >>>>>>> ok, it happened again after 2 days, the process was running about >>>>>>> 3200 >>>>>>> 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 not meant to work >>>>>> 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 >>> changes? >>> >> will do, but I will first attempt to reproduce this on 9.0-RELEASE. >> > 9.0-RELEASE (kernel + userland) hanged today while running 2000 > threads. Next step is to reproduce it with a watchdog+textdump enabled > kernel. And you were still unable to break in DDB, right? Attilio -- Peace can only be achieved by understanding - A. Einstein
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