Hi, thanks for you reply.
On Wed, Jul 17, 2013 at 12:44 AM, Luis Machado <lgust...@codesourcery.com> wrote: > Hi, > > > On 07/16/2013 01:28 PM, Yue Lu wrote: >> >> Hi. >> >> I am writing a debugger demo under GNU/Hurd when I study the gdb source >> code. And I have met a big problem that when I set a breakpoint in the >> inferior, my code can't resume inferior from it. >> >> I can get the exception message from the mach kernel when the inferior >> hit the breakpoint. As soon as I got the exception message, I removed >> the int3, and set the EIP to the previous values, then post a signal >> zero to the inferior by msg_sig_post_untraced_request(). at last I >> called thread_resume() to resume it. But thing goes wrong, the inferior >> is always stops at the breakpoint. and seems never to continue. > > > Some general thoughts... > > Can you make sure the breakpoint has been lifted from the instruction it > replaced? If the breakpoint has been lifted and it is still being hit, then > it sounds like there is some kind of instruction cache problem going on, > where we first need to flush the icache before resuming execution. > > If the icache is the problem, then it sounds like something the kernel > itself needs to address. > > Luis I don't know how to flush the icache off-hand, so I used anther way to bypass this issue. I set the eip to the next instruction's address to bypass the breakpoint ins. But problem seems doesn't go away. -- Yue Lu (陆岳)
