On Sun, Feb 07, 2021 at 02:33:11PM -0700, Alan Somers wrote: > On Fri, Feb 5, 2021 at 10:21 AM Konstantin Belousov <kostik...@gmail.com> > wrote: > > > On Fri, Feb 05, 2021 at 09:01:26AM -0700, Alan Somers wrote: > > > On Fri, Feb 5, 2021 at 7:41 AM Konstantin Belousov <kostik...@gmail.com> > > > wrote: > > > > > > > On Thu, Feb 04, 2021 at 07:53:09PM -0700, Alan Somers wrote: > > > > > On Thu, Feb 4, 2021 at 7:40 PM Konstantin Belousov < > > kostik...@gmail.com> > > > > > wrote: > > > > > > > > > > > On Thu, Feb 04, 2021 at 07:01:30PM -0700, Alan Somers wrote: > > > > > > > On Thu, Feb 4, 2021 at 5:59 PM Konstantin Belousov < > > > > kostik...@gmail.com> > > > > > > > wrote: > > > > > > > > Do you have INVARIANTS enabled? If not, I am curious if > > enabling > > > > them > > > > > > > > would convert that rare page fault into rare "CPU %d has more > > MC > > > > banks" > > > > > > > > assert. > > > > > > > > > > > > > > > > Also might be the output of the > > > > > > > > # for x in $(jot $(sysctl -n hw.ncpu) 0) ; do cpucontrol -m > > 0x179 > > > > > > > > /dev/cpuctl$x; done > > > > > > > > command will show the issue (0x179 is the MCG_CAP MSR). > > > > > > > > You need to load cpuctl(4) if it is not loaded yet. > > > > > > > > > > > > > > > > > > > > > > I don't have INVARIANTS enabled, and I can't enable it on the > > > > production > > > > > > > servers. However, I can turn those three KASSERTs into VERIFYs > > and > > > > see > > > > > > > what happens. Here is what your command shows on the server that > > > > > > panicked: > > > > > > > $ for x in $(jot $(sysctl -n hw.ncpu) 0) ; do sudo cpucontrol -m > > > > 0x179 > > > > > > > /dev/cpuctl$x; done | uniq -c > > > > > > > 16 MSR 0x179: 0x00000000 0x0f000c14 > > > > > > > 16 MSR 0x179: 0x00000000 0x0f000814 > > > > > > > > > > > > It probably explains it, but it would be more telling if you left > > the > > > > > > output as is, so that we can see which CPUs have MCG_CMCI_P (10) > > bit > > > > set. > > > > > > > > > > > > > > > > I didn't sort them, so the first 16 have bit 10 set and the second 16 > > > > > don't. > > > > > > > > > > > > > > > > > > > > > > I suspect that your machine has two sockets, and processor in one > > > > socket > > > > > > has CPUs reporting MCG_CMCI_P, while other processor does not. > > Your SMP > > > > > > is not quite symmetric, perhaps processors were from different > > bins? > > > > > > > > > > I found 2 other servers that exhibit the same problem: the first 16 cores > > > have bit 10 set and the second 16 don't. All 3 have dual Xeon Gold 6142 > > > CPUs and SuperMicro X11DPU motherboards with BIOS revision 5.12. I have > > > other examples of X11DPU motherboards that don't exhibit the problem, but > > > they all have both different CPUs and different BIOS revisions. So I > > can't > > > be sure whether the bug follows the CPU model or the BIOS version. > > I looked at the full spec update errata list for the first gen Skylake > > Xeons, but did not noticed anything relevant. EDS doc does not provide > > much useful info on the MSR 0x179 bit 10 either, except rewording SDM > > definition. > > > > In fact I am not sure but this bit might be writeable by software. Try > > to flip the bit with cpucontrol(8). Might be it is a BIOS bug after all. > > > > If you have Intel representative contact, or Supermicro contact, try to > > engage them. I do not have any further ideas, since spec update does not > > mention the problem. > > > > > > > > > > > > > > > > > > > > > > > > Could be. Is there some MSR that reports a more specific version > > number? > > > > There are CPUID %eax=1 values returned in %eax, but then it requires > > > > some interpretation. > > > > # cpucontrol -i 1 /dev/cpuctl$x > > > > for $x iterating over the cpus. > > > > > > > > > > Apart from the Local APIC ID field, that returns the same value for all > > > processors. > > > > > > Your second patch doesn't cause any obvious problems on my dev system. > > I hope that you would confirm that the issue is solved by it, after some > > time. > > > > Upgrading the BIOS fixed the problem, by clearing the MCG_CMCI_P bit on all > processors. I don't have strong opinions about whether we should commit > kib's patch too. Kib, what do you think?
The patch causes some memory over-use. If this issue is not too widely experienced, I prefer to not commit the patch. _______________________________________________ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
