[Qemu-devel] BUG: QEMU aborts when setting breakpoint in gdb (bisected)

[Luiz Capitulino]

1. Run qemu with gdb server support

   # qemu [...] -s -S

2. Connect gdb and try to set a breakpoint

   $ gdb /path/to/vmlinux
   (gdb) target remote:1234
   (gdb) b secondary_startup_64

3. On qemu terminal

qemu-qmp: 
/home/lcapitulino/work/src/upstream/qmp-unstable/include/qemu/int128.h:22: 
int128_get64: Assertion `!a.hi' failed.
Aborted (core dumped)
   
According to bisect the culprit is:

commit a53ae8e934cd54686875b5bcfc2f434244ee55d6
Author: Marcel Apfelbaum <address@hidden>
Date:   Mon Sep 16 11:21:16 2013 +0300

    hw/pci: partially handle pci master abort

Backtrace:

#0  0x00007fd7882c2a19 in raise () from /lib64/libc.so.6
#1  0x00007fd7882c4128 in abort () from /lib64/libc.so.6
#2  0x00007fd7882bb986 in __assert_fail_base () from /lib64/libc.so.6
#3  0x00007fd7882bba32 in __assert_fail () from /lib64/libc.so.6
#4  0x00007fd78b7402ff in int128_get64 (a=...)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/include/qemu/int128.h:22
#5  address_space_translate_internal (d=<optimized out>, 
addr=18446744067283878160, 
    xlat=0x7fff7c13f498, plen=0x7fff7c13f530, resolve_subpage=<optimized out>)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/exec.c:263
#6  0x00007fd78b740d6c in address_space_translate (as=<optimized out>, 
    address@hidden <address_space_memory>, address@hidden, 
    address@hidden, address@hidden, address@hidden)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/exec.c:277
#7  0x00007fd78b742dc7 in address_space_rw (address@hidden 
<address_space_memory>, 
    addr=18446744071578845456, address@hidden "", address@hidden, 
    address@hidden) at 
/home/lcapitulino/work/src/upstream/qmp-unstable/exec.c:1883
#8  0x00007fd78b744ac1 in cpu_physical_memory_rw (is_write=0, len=18, 
buf=0x7fff7c140620 "", 
    addr=<optimized out>) at 
/home/lcapitulino/work/src/upstream/qmp-unstable/exec.c:1978
#9  cpu_memory_rw_debug (cpu=0x7fd78d63e320, addr=18446744071578845456, 
buf=0x7fff7c140620 "", 
    len=<optimized out>, is_write=0) at 
/home/lcapitulino/work/src/upstream/qmp-unstable/exec.c:2573
#10 0x00007fd78b75594a in target_memory_rw_debug (is_write=false, len=18, 
buf=0x7fff7c140620 "", 
    addr=18446744071578845456, cpu=0x7fd78d63e320)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/gdbstub.c:52
#11 gdb_handle_packet (address@hidden, 
    address@hidden "mffffffff81000110,12")
    at /home/lcapitulino/work/src/upstream/qmp-unstable/gdbstub.c:928
#12 0x00007fd78b7563f8 in gdb_read_byte (ch=55, s=0x7fd78d6a6350)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/gdbstub.c:1402
#13 gdb_chr_receive (opaque=<optimized out>, buf=<optimized out>, 
size=<optimized out>)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/gdbstub.c:1618
#14 0x00007fd78b6ef489 in qemu_chr_be_write (len=<optimized out>, 
    buf=0x7fff7c141740 
"$mffffffff81000110,12#b7s+;xmlRegisters=i386;qRelocInsn+#b5|\377\177", 
    s=0x7fd78d9202c0) at 
/home/lcapitulino/work/src/upstream/qmp-unstable/qemu-char.c:165
#15 tcp_chr_read (chan=<optimized out>, cond=<optimized out>, 
opaque=0x7fd78d9202c0)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/qemu-char.c:2487
#16 0x00007fd78ac02e06 in g_main_context_dispatch () from 
/lib64/libglib-2.0.so.0
#17 0x00007fd78b6c01e8 in glib_pollfds_poll ()
    at /home/lcapitulino/work/src/upstream/qmp-unstable/main-loop.c:189
#18 os_host_main_loop_wait (timeout=<optimized out>)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/main-loop.c:234
#19 main_loop_wait (nonblocking=<optimized out>)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/main-loop.c:483
#20 0x00007fd78b597418 in main_loop () at 
/home/lcapitulino/work/src/upstream/qmp-unstable/vl.c:2014
#21 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>)
    at /home/lcapitulino/work/src/upstream/qmp-unstable/vl.c:4362