Messages in this thread | | | Date | Tue, 20 Jun 2006 14:10:24 -0700 | From | Andrew Morton <> | Subject | Re: [patch] increase spinlock-debug looping timeouts (write_lock and NMI) |
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On Tue, 20 Jun 2006 09:11:36 -0700 (PDT) Dave Olson <olson@unixfolk.com> wrote:
> On Mon, 19 Jun 2006, Andrew Morton wrote: > | > We'll see very long delays when 8 MPI processes exit "simultaneously", and sometimes > | > get NMI, sometimes system hangs, and sometimes just hung up for many seconds (and > | > often in that state, doing sysrq-P or sysrq-T will make things happy again). > | > > | > | OK. I assume these processes have done a mmap(MAP_SHARED) of a lot of > | memory? > > Yep. Some shared with kernel modules, some of device address space. > > | > A typical trace looks like this (on an fc4 2.6.16 kernel): > | > | fc4? You seem to have an RH-FCx which doesn't enable > | CONFIG_DEBUG_SPINLOCK. Or maybe we didn't have all that debug code in > | 2.6.16. Doesn't matter, really. > > Intended to be more or less stock fc4 but with CONFIG_PCI_MSI=y and > 2.6.17-based patch so the 8131 MSI quirk isn't enabled. > > >From the config file: > CONFIG_DEBUG_SPINLOCK=y > CONFIG_DEBUG_SPINLOCK_SLEEP=y
OK, I goofed again.
It would be super-interesting to know whether CONFIG_DEBUG_SPINLOCK=n improves things.
> | With a -stable backport. I suspect this is triggerable on demand. > > So far we've only got the one test case, but it's quite reliable. > We hit one of the 3 cases (long > 60 seconds) "hangs" at exit, > NMI, or dead system hang, every time we run the test case (well, > perhaps 1 out of 20 times everything is "just fine", probably > something perturbs it enough to let one or more processes get > through the critical section ahead of the whole gang).
Reproducability is a win.
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