Re: [patch] Fix linux-nat.c new_lp dropped status

[Pedro Alves <pedro@codesourcery.com>]

On Sunday 18 July 2010 23:08:53, Jan Kratochvil wrote:
> Hi,
> 
> while reading the code it seems to me it can drop non-SIGSTOP status in this
> case.  It can happen only during some racy case while creating a thread,
> I have not tried to exploit it.
> 
> Does the patch make sense?  I have no dependency on it, I just have seen it.

It does to me.  Okay, thanks.

> 
> No regressions on {x86_64,x86_64-m32,i686}-fedora12-linux-gnu.
> 
> 
> Thanks,
> Jan
> 
> 
> --- a/gdb/linux-nat.c
> +++ b/gdb/linux-nat.c
> @@ -2288,6 +2288,23 @@ linux_handle_extended_wait (struct lwp_info *lp, int status,
>  	      linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
>  				    0, signo);
>  	    }
> +	  else
> +	    {
> +	      if (status != 0)
> +		{
> +		  /* We created NEW_LP so it cannot yet contain STATUS.  */
> +		  gdb_assert (new_lp->status == 0);
> +
> +		  /* Save the wait status to report later.  */
> +		  if (debug_linux_nat)
> +		    fprintf_unfiltered (gdb_stdlog,
> +					"LHEW: waitpid of new LWP %ld, "
> +					"saving status %s\n",
> +					(long) GET_LWP (new_lp->ptid),
> +					status_to_str (status));
> +		  new_lp->status = status;
> +		}
> +	    }
>  
>  	  if (debug_linux_nat)
>  	    fprintf_unfiltered (gdb_stdlog,
> 


-- 
Pedro Alves