Month: June 2013

GDB two-breakpoints inter-communication between gdb and gdbstub of qemu

$tcpflow -c -i lo0 port 1234 tcpflow[5508]: 127.000.000.001.01234-127.000.000.001.58366: new flow 127.000.000.001.58366-127.000.000.001.01234: + 127.000.000.001.58366-127.000.000.001.01234: $qSupported:multiprocess+;xmlRegisters=i386;qRelocInsn+#b5 127.000.000.001.01234-127.000.000.001.58366: + 127.000.000.001.01234-127.000.000.001.58366: $PacketSize=1000#f1 127.000.000.001.58366-127.000.000.001.01234: + 127.000.000.001.58366-127.000.000.001.01234: $Hg0#df 127.000.000.001.01234-127.000.000.001.58366: + 127.000.000.001.01234-127.000.000.001.58366: $OK#9a 127.000.000.001.58366-127.000.000.001.01234: + 127.000.000.001.58366-127.000.000.001.01234: $?#3f 127.000.000.001.01234-127.000.000.001.58366: + 127.000.000.001.01234-127.000.000.001.58366: $T05thread:01;#07 127.000.000.001.58366-127.000.000.001.01234: + 127.000.000.001.58366-127.000.000.001.01234: $Hc-1#09 127.000.000.001.01234-127.000.000.001.58366: + 127.000.000.001.01234-127.000.000.001.58366: $OK#9a 127.000.000.001.58366-127.000.000.001.01234: + 127.000.000.001.58366-127.000.000.001.01234: $qC#b4 127.000.000.001.01234-127.000.000.001.58366: + 127.000.000.001.01234-127.000.000.001.58366: $QC1#c5 127.000.000.001.58366-127.000.000.001.01234: + 127.000.000.001.58366-127.000.000.001.01234: $qAttached#8f 127.000.000.001.01234-127.000.000.001.58366:…
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2013/06/16 0

gdb – qemu : two breakpoints flowchart

This is the flowchart for qemu-gdb after i insert two breakpoints at 0x7c00 and 0x7c01, you can see everytime gdb hit a breakpoints, it will remove all breakpoints. And if the current address is the address that hit the breakpoint, when you want to “cont”, gdb will send a “s” command first.


2013/06/12 0

gdb crash, for another debug server

if you are create your own debug server, ¬†gdb will crash, take a look: Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7fffebfff700 (LWP 32202)] 0x000055555577632b in gdb_set_stop_cpu (env=env@entry=0x5555564f6d20) at /root/workspace/qemu-1.5.0/gdbstub.c:2510 2510 gdbserver_state->c_cpu = env; Missing separate debuginfos, use: debuginfo-install SDL-1.2.15-3.fc18.x86_64 cyrus-sasl-lib-2.1.23-37.fc18.x86_64 glib2-2.34.2-2.fc18.x86_64 glibc-2.16-28.fc18.x86_64 libX11-1.5.0-3.fc18.x86_64 libXau-1.0.6-4.fc18.x86_64 libXcursor-1.1.13-2.fc18.x86_64 libXext-1.3.1-2.fc18.x86_64 libXfixes-5.0-3.fc18.x86_64 libXrandr-1.4.0-1.fc18.x86_64 libXrender-0.9.7-2.fc18.x86_64 libpng-1.5.13-1.fc18.x86_64 libxcb-1.9-1.fc18.x86_64 nss-softokn-freebl-3.14.3-1.fc18.x86_64…
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2013/06/12 0