gdb behaviour?

gdb behaviour?

[Jun Koi]

Hi,

I am using gdb to debug Linux guest VM. Steps are like below:
- Start gdbserver in qemu's monitor
- From another console, run gdb and connect it to "localhost:1234"
- Set breakpoints in guest VM

When a breakpoint is hit inside guest, gdb is notified. The problem is
that I cannot send "c" command to gdbserver from gdb to resume the
guest. I always have to run "c" from qemu's monitor, then run another
"c" in gdb. This means I always need 2 "c" commands, in that order.

Is this expected behaviour, or a bug?

I suspect that while guest is stopped for debugging, gdbserver also
stop getting command, hence what I observered. But I looked in the
code, and cannot confirm this. Any hint?


Thanks,
Jun

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Re: gdb behaviour?

[Avi Kivity]

Jun Koi wrote:
> Hi,
>
> I am using gdb to debug Linux guest VM. Steps are like below:
> - Start gdbserver in qemu's monitor
> - From another console, run gdb and connect it to "localhost:1234"
> - Set breakpoints in guest VM
>
> When a breakpoint is hit inside guest, gdb is notified. The problem is
> that I cannot send "c" command to gdbserver from gdb to resume the
> guest. I always have to run "c" from qemu's monitor, then run another
> "c" in gdb. This means I always need 2 "c" commands, in that order.
>
> Is this expected behaviour, or a bug?
>
>   

It's a bug.  When I used gdbserver, it didn't have that behavior, but 
that was close to a year ago so maybe I misremember.

> I suspect that while guest is stopped for debugging, gdbserver also
> stop getting command, hence what I observered. But I looked in the
> code, and cannot confirm this. Any hint?
>   

Maybe... long time since I looked at that code.

How does -no-kvm work?

-- 
error compiling committee.c: too many arguments to function


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