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Re: [pushed] gdbserver: redo stepping over breakpoint that was on top of a permanent breakpoint

On 09/24/2015 09:21 AM, Yao Qi wrote:
Antoine Tremblay <> writes:

Indeed I have a fix for this see :

Ah, I did read your patch, but I forget it when I am fixing this problem.

Np, I think that patch is valid with the scenario you mention below, however since it won't work properly as reinsert_addr doesn't work at this stage I think it may be better to introduce it when I post the single stepping support ?

It can be triggered when GDBserver steps over its breakpoints, what I
did is to pass 1 to thread_db_init, so that GDBserver will insert
breakpoint on __nptl_create_event.  Once a new thread is created, and
hits this breakpoint, GDBserver will step over this breakpoint.

Haa I had missed that scenario!

--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -3010,7 +3010,8 @@ linux_wait_1 (ptid_t ptid,
      Advance the PC manually past the breakpoint, otherwise the
      program would keep trapping the permanent breakpoint forever.  */
   if (!ptid_equal (step_over_bkpt, null_ptid)
-      && event_child->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
+      && event_child->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
+      && gdb_breakpoint_here (event_child->stop_pc))
       int increment_pc = 0;
       CORE_ADDR stop_pc = event_child->stop_pc;

This won't work as that single step breakpoint is not a gdb breakpoint we need to check for a reinsert breakpoint like the patch I mentioned.

I tested the scenario with my patch and the issue is solved.

Note however I'm a bit concerted about the hack to remote_check_symbols. I need to dig into it to understand that one should we expect it to work without this hack ?

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