Re: [PATCH 2/2] gdbstub: i386: Fix gdb_get_reg16() parameter to unbreak gdb

[Philippe Mathieu-Daudé]

On 4/9/20 6:49 PM, Peter Xu wrote:

We should only pass in gdb_get_reg16() with the GByteArray* object
itself, no need to shift.  Without this patch, gdb remote attach will
crash QEMU.

You are correct.

Fixes: a010bdbe719 ("extend GByteArray to read register helpers")

Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>

Same problem in m68k_fpu_gdb_get_reg().

TODO for 5.1, rename mem_buf -> array.

Cc: Alex Bennée <alex.ben...@linaro.org>
Cc: Philippe Mathieu-Daudé <phi...@redhat.com>
Signed-off-by: Peter Xu <pet...@redhat.com>
---
  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;