Re: panic: pmap_tlb_pendcount > 0 failed

[Thomas Klausner <wiz%NetBSD.org@localhost>]

On Thu, Mar 28, 2013 at 12:29:40AM +0100, Thomas Klausner wrote:
> Hi!
> 
> I've just run a GENERIC-6.99.18/amd64 kernel from today on a newly
> acquired machine, and see:
> 
> ...
> acpicpu11 at cpu11: ACPI CPU
> panic: kernel diagnostic assertion "pmap_tlb_pendcount > 0" failed: file 
> "../../../../arch/x86/x86/pmap_tlb.c", line 451
> fatal breakpoint trap in supervisor mode
> trap type 1 code 0 rip ffffffff802546ed cs 8 rflags 46 cr2 0 ilevel 0 rsp 
> fffffe813a6369e0
> curlwp 0xfffffe887556bb20 pid 0.71 lowest kstrack 0xfffffe813a633000
> Stopped in pid 0.71 (system) at netbsd:breakpoint+0x5: leave
> db{10}> bt
> breakpoint() at netbsd:breakpoint+0x5
> vpanic() at netbsd:vpanic+0x136
> kern_assert() at netbsd:kern_assert+0x48
> pmap_tlb_intr() at netbsd:pmap_tlb_intr+0xf4
> DDB lost frame for netbsd:Xinter_lapic_tlb+0x98, trying 0xfffffe813636aa0
> Xintr_lapic_tlb() at netbsd:Xinter_lapic_tlb+0x98
> --- interrupt ---
> 246:
> db{10}>
> 
> dmesg is too long to copy by hand, but available on the db prompt.
> It's a Supermicro X9SRi with a Xeon E5-1650@3.20GHz.

PR 47437 by Taylor R Campbell might be related, he writes:

   Sometimes when I boot a many-core machine, during autoconf I
   get a panic after the ACPI CPU devices are configured.  I've
   seen the panic several times; last night I caught it on the
   serial console for the first time with ddb and grabbed a stack
   trace.  I believe it always happens after all the acpicpuN
   devices are attached, but I'm not sure.

so it's the same place in the boot process; but his panic is

panic: kernel diagnostic assertion "pmap_tlb_pendcount < ncpu" failed: file 
"/home/riastradh/netbsd/current/src/sys/arch/x86/x86/pmap_tlb.c", line 434

Is there some mutex protection missing for pmap_tlb_pendcount?
 Thomas