Very bizarre behavior ARM64 (Pi3)

[Karl Denninger]

I managed to get around the Crochet blow-up I reported the other day
with another svn update, and now can Crochet myself a running image for
the Pi3 which boots and (at least at first blush) works.

But I have code that has been running on the Pi3 (and also on the Pi2,
along with other architectures) for quite some time that no longer runs
when compiled on that newly-built OS.  It compiles without warnings or
errors but blows up immediately when executed.

I just tried to roll that build forward to the newly-built (FreeBSD
12.0-CURRENT #0 r325681M: Fri Nov 10 19:31:28 CST 2017)  -HEAD and am
getting really bizarre core dumps, including (if compiled using OpenSSL
libraries) a crash on initialization claiming unknown opcodes in the
compiled binary.

root at rpi3:/data/HD-MCP # lldb hd-mcp
(lldb) target create "hd-mcp"
Current executable set to 'hd-mcp' (aarch64).
(lldb) run -n
Process 1101 launching
Process 1101 launched: '/data/HD-MCP/hd-mcp' (aarch64)
Process 1101 stopped
* thread #1, name = 'hd-mcp', stop reason = signal SIGILL: illegal trap
    frame #0: 0x00000000403342e8
->  0x403342e8: .long  0x0ee0e000                ; unknown opcode
    0x403342ec: ret
    0x403342f0: stp    x28, x19, [sp, #-0x20]!
    0x403342f4: stp    x29, x30, [sp, #0x10]
(lldb) bt
* thread #1, name = 'hd-mcp', stop reason = signal SIGILL: illegal trap
  * frame #0: 0x00000000403342e8
    frame #1: 0x0000000040082ad8
    frame #2: 0x0000000040081ab4
(lldb)

If I compile and link with OpenSSL omitted (which is an option in the
software in question) then I get blowups shortly after the software
starts implying the stack is getting smashed in bizarre ways that don't
make any sense.

The same source has been running for months uninterrupted on 11.x hosted
on a Pi2 and used to run just fine on a Pi3 from a build I last updated
back in February.

To top it off lldb blows up if I set a breakpoint (or get a SEGV and
trap back to it) and try to print anything out of the current frame
(e.g. the variables in the function that blew) so it's basically
impossible to figure out what's getting hammered in the stack if I leave
the OpenSSL libraries out.

Are there known issues with the arm64 architecture in -HEAD at present?

-- 
Karl Denninger
karl at denninger.net <mailto:karl at denninger.net>
/The Market Ticker/
/[S/MIME encrypted email preferred]/
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