Re: [PATCH v2] gdbstub: Fix segment fault for i386 target

["Alex Bennée" <alex.bennee@linaro.org>]

Changbin Du <changbin.du@gmail.com> writes:

> With GByteArray, we should pass the object itself but not to plus an offset.
>
> gdb log:
> Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
> __memmove_avx_unaligned_erms () at ../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:384
> 384	../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S: No such file or directory.
>
> Fixes: a010bdbe71 ("gdbstub: extend GByteArray to read register helpers")
> Signed-off-by: Changbin Du <changbin.du@gmail.com>
>
> ---
> v2: remove m68k fix since it's already queued.

I also have Peter Xu's fix for i386:

  https://patchew.org/QEMU/20200409211529.5269-1-alex.bennee@linaro.org/20200409211529.5269-10-alex.bennee@linaro.org/

But I'll happily add your Reported-by credit to that patch.

> ---
>  target/i386/gdbstub.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/target/i386/gdbstub.c b/target/i386/gdbstub.c
> index f3d23b614e..b98a99500a 100644
> --- a/target/i386/gdbstub.c
> +++ b/target/i386/gdbstub.c
> @@ -106,7 +106,7 @@ int x86_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
>      } else if (n >= IDX_FP_REGS && n < IDX_FP_REGS + 8) {
>          floatx80 *fp = (floatx80 *) &env->fpregs[n - IDX_FP_REGS];
>          int len = gdb_get_reg64(mem_buf, cpu_to_le64(fp->low));
> -        len += gdb_get_reg16(mem_buf + len, cpu_to_le16(fp->high));
> +        len += gdb_get_reg16(mem_buf, cpu_to_le16(fp->high));
>          return len;
>      } else if (n >= IDX_XMM_REGS && n < IDX_XMM_REGS + CPU_NB_REGS) {
>          n -= IDX_XMM_REGS;


-- 
Alex Bennée