Jun Koi wrote: > On Tue, Apr 27, 2010 at 5:10 PM, Jan Kiszka <jan.kis...@siemens.com> wrote: >> Jun Koi wrote: >>> Hi, >>> >>> I am trying to debug a VM using gdb. I connected gdb to Qemu (latest >>> code from git repo), and issued below command: >>> >>> ... >>> (gdb) watch *0x77f44cd8 >>> (gdb) c >>> >>> The idea is to catch the write access to address 0x77f44cd8. >>> >>> But after the "c" command, I saw that the window title of my VM >>> continuously flip between "QEMU [Stopped]" and "QEMU", non-stop. >>> This makes the VM unusable. >>> >>> Is it a bug? Anybody sees the same problem? >> I would bet your watchpoint was established by gdb as a software >> watchpoint. In that case gdb will step through the target, checking >> after each instruction if the memory changed. > > But that is certainly not the reason of the symptom I saw. >
So what does "i b" report about your watchpoint? Hard or soft? > >> Is that address valid at the time gdb wants to install it? I saw gdb >> choosing a software watchpoint before when it wasn't. > > Yes, that address is valid. You could also try "set debug remote 1" to see what gdb does when it stops and resumes the guest continuously. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
