Date: Fri, 02 Nov 2007 12:50:44 -0800 From: Nate Lawson <nate@root.org> To: Glen <glen.leeder@nokia.com> Cc: ACPI mailing list <freebsd-acpi@freebsd.org> Subject: Re: SMP system shutdown hang (acpi_cpu_shutdown - smp_rendezvous) Message-ID: <472B8DA4.1000308@root.org> In-Reply-To: <472A53B2.6030901@nokia.com> References: <472A53B2.6030901@nokia.com>
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Glen wrote: > Hi, > > I have been seeing intermittent hangs in the acpi shutdown code on a > Intel 2.4GHz 8 CPU system. I am running a with a Freebsd6.1 code base > but cannot see a reason why this can't happen in other Freebsd versions. > The hang is very irregular, I am recreating it using an expect script > that repeatedly reboots the system. Sometimes, I can do up to 200 > reboots before observing the hang, sometimes, it happens after 5-20 > reboots. > > It has been difficult to pin down the hang as the system is not > responding to NMI events but using breakpoints I believe the hang is in > acpi_cpu.c:acpi_cpu_shutdown with the call to smp_rendezvous. > > My theory is that one of the CPUs does not respond to ipi_all_but_self > and that all the other CPUs are waiting for it in smp_rendezvous_action. > The smp_rv_waiters[0] < mp_ncpus condition never gets met and the system > hangs. This maybe happen due to other activity (or a deadlock?) on that > CPU. Fix committed, I'll do my best to get it into 7.0 and 6.3. -- Nate
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