Date: Wed, 03 Nov 2010 10:48:50 +0200 From: Andriy Gapon <avg@freebsd.org> To: Dan Allen <danallen46@airwired.net> Cc: Sergey Kandaurov <pluknet@gmail.com>, FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org> Subject: Re: Fatal trap 18 Message-ID: <4CD121F2.3010508@freebsd.org> In-Reply-To: <4CD11FE9.8050105@freebsd.org> References: <68E248E0-8619-4859-BFFE-1B5F5ABBC51F@airwired.net> <AANLkTik0=x6h3YK0F_yrRJ_MGHp9pf8dVubbEwpmAa1y@mail.gmail.com> <4CD11FE9.8050105@freebsd.org>
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on 03/11/2010 10:40 Andriy Gapon said the following:
> This problem seems to happen only on SMP systems that for some reason run as UP.
> E.g. because ACPI and/or APIC are disabled.
> Or some other BIOS configuration.
> But I am not sure what exactly is the case here.
> Verbose dmesg from a working kernel would be helpful.
I still would like to see verbose dmesg, just to be sure what's going on.
Here's a patch that I have in mind for this issue, if it is what I think it is.
If you have amd64 system, the patch is equally applicable to
sys/amd64/amd64/mp_machdep.c.
Index: sys/i386/i386/mp_machdep.c
===================================================================
--- sys/i386/i386/mp_machdep.c (revision 214619)
+++ sys/i386/i386/mp_machdep.c (working copy)
@@ -286,6 +286,9 @@
cpu_logical++;
}
+ KASSERT(cpu_cores >= 1 && cpu_logical >= 1,
+ ("topo_probe_0x4 couldn't find BSP"));
+
cpu_cores /= cpu_logical;
hyperthreading_cpus = cpu_logical;
}
@@ -357,7 +360,9 @@
return;
logical_cpus_mask = 0;
- if (cpu_vendor_id == CPU_VENDOR_AMD)
+ if (mp_ncpus <= 1)
+ cpu_cores = cpu_logical = 1;
+ else if (cpu_vendor_id == CPU_VENDOR_AMD)
topo_probe_amd();
else if (cpu_vendor_id == CPU_VENDOR_INTEL) {
/*
@@ -379,10 +384,8 @@
* Fallback: assume each logical CPU is in separate
* physical package. That is, no multi-core, no SMT.
*/
- if (cpu_cores == 0)
- cpu_cores = 1;
- if (cpu_logical == 0)
- cpu_logical = 1;
+ if (cpu_cores == 0 || cpu_logical == 0)
+ cpu_cores = cpu_logical = 1;
cpu_topo_probed = 1;
}
--
Andriy Gapon
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