Re: [Qemu-devel] target-s390x: assertion failure in op_risbg

[Richard Henderson <rth@twiddle.net>]

On 11/07/2017 12:41 PM, Peter Maydell wrote:
> This is from https://bugs.launchpad.net/qemu/+bug/1701798, but
> that's quite a large thing, so here's the s390 specific part.
> 
> On an ubuntu xenial install:
> 
> $ apt install g++-5-s390x-linux-gnu
> $ cat hello.c
> #include <stdio.h>
> int main(void) {
>     printf("hello world\n");
>     return 0;
> }
> $ s390x-linux-gnu-gcc-5 -O hello.c -o hello.s390x
> $ QEMU_LD_PREFIX=/usr/s390x-linux-gnu/ gdb --args
> ~/linaro/qemu-from-laptop/qemu/build/all-linux-static/s390x-linux-user/qemu-s390x
> ./hello.s390x
> [...]
> (gdb) r
> [...]
> Thread 1 "qemu-s390x" received signal SIGABRT, Aborted.
> 0x0000000060215018 in raise ()
> (gdb) bt
> #0  0x0000000060215018 in raise ()
> #1  0x000000006021573a in abort ()
> #2  0x0000000060079a96 in op_risbg (s=0x7fffffffda10, o=0x7fffffffd950)
>     at /home/petmay01/linaro/qemu-from-laptop/qemu/target/s390x/translate.c:3450
> #3  0x0000000060082c8b in translate_one (env=0x627f0350, s=0x7fffffffda10)
>     at /home/petmay01/linaro/qemu-from-laptop/qemu/target/s390x/translate.c:5824
> #4  0x0000000060082f3f in gen_intermediate_code (cs=0x627e80b0,
>     tb=0x60794d40 <static_code_gen_buffer+56064>)
>     at /home/petmay01/linaro/qemu-from-laptop/qemu/target/s390x/translate.c:5925
> #5  0x00000000600369aa in tb_gen_code (cpu=0x627e80b0, pc=274886359240,
>     cs_base=0, flags=3, cflags=0)
> 
> This is because in op_risbg() we abort() if s->fields->op2 is not
> one of 0x55, 0x5d, 0x51. In this case it is 0x59. I don't know enough
> s390 to know what this might be, but we shouldn't really abort()
> inside QEMU for unimplemented guest insns.

Patch sent.  Since you have a testcase created, can you smoke test it?
I decline to download the necessaries while riding on this bus.  ;-)


r~