architecture: 0.748
mistranslation: 0.703
risc-v: 0.654
device: 0.565
semantic: 0.515
x86: 0.371
socket: 0.288
arm: 0.281
files: 0.261
register: 0.250
ppc: 0.249
performance: 0.237
debug: 0.236
network: 0.230
assembly: 0.222
vnc: 0.206
user-level: 0.202
hypervisor: 0.195
graphic: 0.178
PID: 0.173
virtual: 0.167
permissions: 0.165
peripherals: 0.122
kernel: 0.121
TCG: 0.111
VMM: 0.097
boot: 0.090
i386: 0.076
KVM: 0.048

RISC-V Disassembler/translator instruction decoding disagreement


When running QEMU V3.1.0 for platform  RISC-V, 64bit, Spike V1.10 with "-d in_asm -singlestep -D qemu_log.txt", my (faulty) test code brought up this message in the logs:

  0x000000008002cade:  051300009517e2bf  illegal         
  Disassembler disagrees with translator over instruction decoding
  Please report this to <email address hidden>


You may want to resolve the disagreement.

Axel

Hi Axel,

can you link us to your test code, such that we can try to reproduce it.

Cheers,
Bastian

Sorry, I don't have the test code, since this was created by a memory corruption. However, the way I understand the message is, that there is some internal disagreement how to decode the op-code "051300009517e2bf" - which mige be an invalid opcode anyway. So a simple test application would just consist of this opcode.

I've encountered this message before for invalid instructions, and it often doesn't really mean there was an error. In particular for variable instruction length ISAs you'll see the error if the translator reads part of the insn and determines that it's invalid without needing to read the rest of it -- https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg06845.html talks about a case of that for x86.


The QEMU project is currently considering to move its bug tracking to another system. For this we need to know which bugs are still valid and which could be closed already. Thus we are setting older bugs to "Incomplete" now.
If you still think this bug report here is valid, then please switch the state back to "New" within the next 60 days, otherwise this report will be marked as "Expired". Or mark it as "Fix Released" if the problem has been solved with a newer version of QEMU already. Thank you and sorry for the inconvenience.


This is an automated cleanup. This bug report has been moved
to QEMU's new bug tracker on gitlab.com and thus gets marked
as 'expired' now. Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/53