MCA unrecoverable machine check exception on APU2

Shawn Webb shawn.webb at
Sun May 1 12:35:15 UTC 2016

Hey All,

I'm getting this panic. I'm not sure if it's a problem with the OS or
the hardware as this is a bit too low-level for me. Here's the dmesg
output along with the stack trace:

MCA: Bank 0, Status 0xb400000000000135
MCA: Global Cap 0x0000000000000106, Status 0x0000000000000004
MCA: Vendor "AuthenticAMD", ID 0x730f01, APIC ID 3
MCA: Address 0x44e9830
panic: Unrecoverable machine check exception
cpuid = 3
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe00f53cb390
vpanic() at vpanic+0x182/frame 0xfffffe00f53cb410
panic() at panic+0x43/frame 0xfffffe00f53cb470
mca_intr() at mca_intr+0x6b/frame 0xfffffe00f53cb490
trap() at trap+0xa8/frame 0xfffffe00f53cb6a0
calltrap() at calltrap+0x8/frame 0xfffffe00f53cb6a0
--- trap 0x1c, rip = 0xffffffff80b6ffe1, rsp = 0xfffffe00f53cb770, rbp = 0xfffffe00f53cb7f0 ---
callout_process() at callout_process+0x131/frame 0xfffffe00f53cb7f0
handleevents() at handleevents+0x16d/frame 0xfffffe00f53cb830
timercb() at timercb+0x227/frame 0xfffffe00f53cb880
lapic_handle_timer() at lapic_handle_timer+0x9f/frame 0xfffffe00f53cb8c0
Xtimerint() at Xtimerint+0x8c/frame 0xfffffe00f53cb8c0
--- interrupt, rip = 0xffffffff80b85a39, rsp = 0xfffffe00f53cb990, rbp = 0xfffffe00f53cba70 ---
sched_idletd() at sched_idletd+0x439/frame 0xfffffe00f53cba70
fork_exit() at fork_exit+0x84/frame 0xfffffe00f53cbab0
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe00f53cbab0
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
KDB: enter: panic
[ thread pid 11 tid 100006 ]
Stopped at      kdb_enter+0x3b: movq    $0,kdb_why

This is running HardenedBSD 11-CURRENT/amd64 on the PC-Engines APU2. Is
this worth filing a bug report upstream with FreeBSD or is this a
hardware bug?


Shawn Webb

GPG Key ID:          0x6A84658F52456EEE
GPG Key Fingerprint: 2ABA B6BD EF6A F486 BE89  3D9E 6A84 658F 5245 6EEE
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