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[Qemu-devel] [Bug 640213] [NEW] QEMU does not communicate properly with
From: |
Ted Harkington |
Subject: |
[Qemu-devel] [Bug 640213] [NEW] QEMU does not communicate properly with GDB with a 64 bit guest |
Date: |
Thu, 16 Sep 2010 06:49:02 -0000 |
Public bug reported:
I have been trying to figure out why I cannot debug a 64 bit kernel of
my own invention.
I launch qemu-system-x86_64 with the -s -S flags, we also specify -cpu
core2duo -vga std and a -hda with an ext2 FS holding our multiboot
kernel and GRUB2.
When I try to set breakpoints and "continue" in GDB (7.2) using the very
latest HEAD (b6601141cd2a170dfe773987b06f716a190ea7e0) or 0.12.0 or
0.12.5 or 13.0.rc0 or 13.0.rc1, I get failures of the same nature:
0x0000000000000000 in ?? ()
(gdb) break main
Breakpoint 1 at 0x101730: file src/kernel/init.c, line 18.
(gdb) c
Program received signal SIGTRAP, Trace/breakpoint trap.
0x0000000000000000 in ?? ()
(gdb)
Note that in this case, main lies in 64 bit mode. However, trying to
break on _start yields virtually the same effect and _start is 32 bit
code.
By doing a git bisect, I managed to narrow the commit that introduced this bug
to 5f30fa18ad043a841fe9f0c3917ac60f2519ebd1. Reverting this commit on HEAD
seemingly fixed the problem for both the 32 bit and 64 bit cases.
I might be doing something incorrectly on my end but this seemed to fix the
problem.
Perhaps the pertinent thing to do would be to revert
5f30fa18ad043a841fe9f0c3917ac60f2519ebd1 as it seems to do nothing but
break things unless, of course, this would only break something that I
am not aware of further.
** Affects: qemu
Importance: Undecided
Status: New
--
QEMU does not communicate properly with GDB with a 64 bit guest
https://bugs.launchpad.net/bugs/640213
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
Status in QEMU: New
Bug description:
I have been trying to figure out why I cannot debug a 64 bit kernel of my own
invention.
I launch qemu-system-x86_64 with the -s -S flags, we also specify -cpu core2duo
-vga std and a -hda with an ext2 FS holding our multiboot kernel and GRUB2.
When I try to set breakpoints and "continue" in GDB (7.2) using the very latest
HEAD (b6601141cd2a170dfe773987b06f716a190ea7e0) or 0.12.0 or 0.12.5 or 13.0.rc0
or 13.0.rc1, I get failures of the same nature:
0x0000000000000000 in ?? ()
(gdb) break main
Breakpoint 1 at 0x101730: file src/kernel/init.c, line 18.
(gdb) c
Program received signal SIGTRAP, Trace/breakpoint trap.
0x0000000000000000 in ?? ()
(gdb)
Note that in this case, main lies in 64 bit mode. However, trying to break on
_start yields virtually the same effect and _start is 32 bit code.
By doing a git bisect, I managed to narrow the commit that introduced this bug
to 5f30fa18ad043a841fe9f0c3917ac60f2519ebd1. Reverting this commit on HEAD
seemingly fixed the problem for both the 32 bit and 64 bit cases.
I might be doing something incorrectly on my end but this seemed to fix the
problem.
Perhaps the pertinent thing to do would be to revert
5f30fa18ad043a841fe9f0c3917ac60f2519ebd1 as it seems to do nothing but break
things unless, of course, this would only break something that I am not aware
of further.
- [Qemu-devel] [PATCH v2 00/19] Monitor: split HMP and QMP dispatch tables, Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 01/19] Monitor: Introduce search_dispatch_table(), Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 02/19] QMP: handle_qmp_command(): Move 'cmd' sanity check, Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 03/19] QMP: Don't use do_info(), Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 04/19] Monitor: Drop QMP bits from do_info(), Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 05/19] Monitor: Drop is_async_return(), Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 06/19] Monitor: Convert do_info() back to HMP, Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 07/19] Monitor: Introduce the qmp-commands.hx file, Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 09/19] QMP: Introduce command dispatch table, Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 08/19] QMP: Introduce qmp_find_cmd(), Luiz Capitulino, 2010/09/30
- [Qemu-devel] [PATCH 10/19] QMP: Introduce query commands dispatch table, Luiz Capitulino, 2010/09/30