Troubles with Shenandoah

[Aleksey Shipilev]

On 4/7/19 10:57 PM, Simone Bordet wrote:
> On Sun, Apr 7, 2019 at 7:52 PM Simone Bordet <simone.bordet at gmail.com> wrote:
>> Will try the fastdebug build and report back.
> 
> I got a crash with fastdebug, attached hs_err.
> 
> Let me know if it's helpful.
> I'm interested in the details of the failure, if the file has enough
> information.

I think it has.

Signal is raised trying to access 0x00007f006b8a54fc:
  siginfo: si_signo: 11 (SIGSEGV), si_code: 2 (SEGV_ACCERR), si_addr: 0x00007f006b8a54fc

...which looks to come from %rbx:
  RBX=0x00007f006b8a54fc: <offset 0x00000000000e04fc> in /lib/x86_64-linux-gnu/libnsl.so.1 at
0x00007f006b7c5000

...and Instructions section disassembly shows this:
 https://onlinedisassembler.com/odaweb/uV5P7D1q/0

 00000016 48 bb fc 54 8a 6b 00 7f 00 00    movabs rbx,0x7f006b8a54fc
 00000020 80 3c 0b 00                      cmp    BYTE PTR [rbx+rcx*1],0x0 <-- SEGV here

It looks like bad constant oop in the generated code. -XX:ScavengeRootsInCode=0 might be a plausible
workaround.

-Aleksey