SIGILL crashes JVM on PPC64 LE

[Volker Simonis]

Hi Gustavo,

thanks for the bug report. The hs_err file you provided indicates that
this crash happened with Ubuntu's openjdk 8 version. Can you still
reproduce this with the the newest jdk9 builds?

Also, I can see from the hs_err file that the crash happened in the C2
compiled method java.util.TimSort.countRunAndMakeAscending which
doesn't seem to be related to nio and unsafe.

Ideally, you could post an easy test case to reproduce the problem. If
that's not possible, it would be helpful if you could post the output
of a failing run with
"-XX:CompileCommand=print,java.util.TimSort::countRunAndMakeAscending
-XX:CompileCommand=option,java.util.TimSort::countRunAndMakeAscending,PrintOptoAssembly".
In order to get the disassembly output for compiled methods you have
to build the hsdis library from hotspot/src/share/tools/hsdis (it has
a README with build instructions).

Regards,
Volker


On Thu, May 12, 2016 at 12:32 AM, Gustavo Romero
<gromero at linux.vnet.ibm.com> wrote:
> Hi
>
> I'm getting a nasty SIGILL that crashes the JVM on PPC64 LE.
>
> hs_err log:
> http://hastebin.com/raw/fovagunaci
>
> The application employs methods from both java.nio.ByteBuffer and
> sun.misc.Unsafe classes in order to write and read from an allocated buffer.
>
> A interesting thing is that after debugging the instruction that caused the
> said SIGILL:
>
>    0x3fff902839a4:      cmpwi   cr6,r17,0
>    0x3fff902839a8:      beq     cr6,0x3fff90283ae4
>    0x3fff902839ac:      .long 0xea2f0013 <============ illegal instruction
>    0x3fff902839b0:      add     r15,r15,r17
>    0x3fff902839b4:      add     r14,r17,r14
>
> I found that when its endianness is changed it turns out to be a valid
> instruction: vsel v24,v0,v5,v31
>
> However, I'm still unable to determine if it's an application issue, something
> with JVM unsafe interface code, or something else.
>
> Any clue on how to narrow down this SIGILL?
>
> Thank you!
>
> Regards,
> Gustavo
>