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Pedro Alves 3b27ef472d linux-nat.c: fix a few lin_lwp_attach_lwp issues
This function has a few latent bugs that are triggered by a non-stop
mode test that will be added in a subsequent patch.

First, as described in the function's intro comment, the function is
supposed to return 1 if we're already auto attached to the thread, but
haven't processed the PTRACE_EVENT_CLONE event of its parent thread
yet.

Then, we may find that we're trying to attach to a clone child that
hasn't yet stopped for its initial stop, and therefore 'waitpid(...,
WNOHANG)' returns 0.  In that case, we're currently adding the LWP to
the stopped_pids list, which results in linux_handle_extended_wait
skipping the waitpid call on the child, and thus confusing things
later on when the child eventually reports the stop.

Then, the tail end of lin_lwp_attach_lwp always sets the
last_resume_kind of the LWP to resume_stop, which is wrong given that
the user may be doing "info threads" while some threads are running.

And then, the else branch of lin_lwp_attach_lwp always sets the
stopped flag of the LWP.  This branch is reached if the LWP is the
main LWP, which may well be running at this point (to it's wrong to
set its 'stopped' flag).

AFAICS, there's no reason anymore for special-casing the main/leader
LWP here:

- For the "attach" case, linux_nat_attach already adds the main LWP to
the lwp list, and sets its 'stopped' flag.

- For the "run" case, after linux_nat_create_inferior, end up in
linux_nat_wait_1 here:

  /* The first time we get here after starting a new inferior, we may
     not have added it to the LWP list yet - this is the earliest
     moment at which we know its PID.  */
  if (ptid_is_pid (inferior_ptid))
    {
      /* Upgrade the main thread's ptid.  */
      thread_change_ptid (inferior_ptid,
			  ptid_build (ptid_get_pid (inferior_ptid),
				      ptid_get_pid (inferior_ptid), 0));

      lp = add_initial_lwp (inferior_ptid);
      lp->resumed = 1;
    }

... which adds the LWP to the LWP list already, before
lin_lwp_attach_lwp can ever be reached.

gdb/ChangeLog:
2015-02-20  Pedro Alves  <palves@redhat.com>

	* linux-nat.c (lin_lwp_attach_lwp): No longer special case the
	main LWP.  Handle the case of waitpid returning 0 if we're already
	attached to the LWP.  Don't set the LWP's last_resume_kind to
	resume_stop if we already knew about the LWP.
	(linux_nat_filter_event): Add debug logs.
2015-02-20 20:21:59 +00:00
bfd S390: Support new vector register sections 2015-02-20 10:39:53 +01:00
binutils S390: Support new vector register sections 2015-02-20 10:39:53 +01:00
config
cpu
elfcpp [gold] Recognize DWARF5/GCC5 DW_LANG_Fortran03 and DW_LANG_Fortran08. 2015-02-17 08:08:24 +01:00
etc
gas gas doc warning fixes 2015-02-19 14:14:51 +10:30
gdb linux-nat.c: fix a few lin_lwp_attach_lwp issues 2015-02-20 20:21:59 +00:00
gold Fix gold error: hidden symbol '...' is not defined locally 2015-02-18 22:51:14 +10:30
gprof
include S390: Support new vector register sections 2015-02-20 10:39:53 +01:00
intl
ld Use nm/readelf with "failif" 2015-02-19 04:45:27 -08:00
libdecnumber
libiberty
opcodes Wrap a few opcodes headers in extern "C" for C++ 2015-02-19 22:45:47 +00:00
readline
sim sim: drop unused headers 2015-02-20 00:16:14 -05:00
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.