On Linux, we need to explicitly ptrace attach to all lwps of a
process. Because GDB might not be connected yet when an attach is
requested, and thus it may not be possible to activate thread_db, as
that requires access to symbols (IOW, gdbserver --attach), a while ago
we make linux_attach loop over the lwps as listed by /proc/PID/task to
find the lwps to attach to.
linux_attach_lwp_1 has:
...
if (initial)
/* If lwp is the tgid, we handle adding existing threads later.
Otherwise we just add lwp without bothering about any other
threads. */
ptid = ptid_build (lwpid, lwpid, 0);
else
{
/* Note that extracting the pid from the current inferior is
safe, since we're always called in the context of the same
process as this new thread. */
int pid = pid_of (current_inferior);
ptid = ptid_build (pid, lwpid, 0);
}
That "safe" comment referred to linux_attach_lwp being called by
thread-db.c. But this was clearly missed when a new call to
linux_attach_lwp_1 was added to linux_attach. As a result,
current_inferior will be set to some random process, and non-initial
lwps of the second inferior get assigned the pid of the wrong
inferior. E.g., in the case of attaching to two inferiors, for the
second inferior (and so on), non-initial lwps of the second inferior
get assigned the pid of the first inferior. This doesn't trigger on
the first inferior, when current_inferior is NULL, add_thread switches
the current inferior to the newly added thread.
Rather than making linux_attach switch current_inferior temporarily
(thus avoiding further reliance on global state), or making
linux_attach_lwp_1 get the tgid from /proc, which add extra syscalls,
and will be wrong in case of the user having originally attached
directly to a non-tgid lwp, and then that lwp spawning new clones (the
ptid.pid field of further new clones should be the same as the
original lwp's pid, which is not the tgid), we note that callers of
linux_attach_lwp/linux_attach_lwp_1 always have the right pid handy
already, so they can pass it down along with the lwpid.
The only other reason for the "initial" parameter is to error out
instead of warn in case of attach failure, when we're first attaching
to a process. There are only three callers of
linux_attach_lwp/linux_attach_lwp_1, and each wants to print a
different warn/error string, so we can just move the error/warn out of
linux_attach_lwp_1 to the callers, thus getting rid of the "initial"
parameter.
There really nothing gdbserver-specific about attaching to two
threaded processes, so this adds a new test under gdb.multi/. The
test passes cleanly against the native GNU/Linux target, but
fails/triggers the bug against GDBserver (before the patch), with the
native-extended-remote board (as plain remote doesn't support
multi-process).
Tested on x86_64 Fedora 17, with the native-extended-gdbserver board.
gdb/gdbserver/
2014-04-25 Pedro Alves <palves@redhat.com>
PR server/16255
* linux-low.c (linux_attach_fail_reason_string): New function.
(linux_attach_lwp): Delete.
(linux_attach_lwp_1): Rename to ...
(linux_attach_lwp): ... this. Take a ptid instead of a pid as
argument. Remove "initial" parameter. Return int instead of
void. Don't error or warn here.
(linux_attach): Adjust to call linux_attach_lwp. Call error on
failure to attach to the tgid. Call warning when failing to
attach to an lwp.
* linux-low.h (linux_attach_lwp): Take a ptid instead of a pid as
argument. Remove "initial" parameter. Return int instead of
void. Don't error or warn here.
(linux_attach_fail_reason_string): New declaration.
* thread-db.c (attach_thread): Adjust to linux_attach_lwp's
interface change. Use linux_attach_fail_reason_string.
gdb/
2014-04-25 Pedro Alves <palves@redhat.com>
PR server/16255
* common/linux-ptrace.c (linux_ptrace_attach_warnings): Rename to ...
(linux_ptrace_attach_fail_reason): ... this. Remove "warning: "
and newline from built string.
* common/linux-ptrace.h (linux_ptrace_attach_warnings): Rename to ...
(linux_ptrace_attach_fail_reason): ... this.
* linux-nat.c (linux_nat_attach): Adjust to use
linux_ptrace_attach_fail_reason.
gdb/testsuite/
2014-04-25 Simon Marchi <simon.marchi@ericsson.com>
Pedro Alves <palves@redhat.com>
PR server/16255
* gdb.multi/multi-attach.c: New file.
* gdb.multi/multi-attach.exp: New file.
I noticed today that multi-arch-exec.exp was failing in parallel mode.
The bug is that multi-arch-exec.c assumes the non-parallel directory
layout.
This patch fixes the problem using the same "BASEDIR" approach used in
other tests.
Tested both ways on x86-64 Fedora 18.
I'm checking this in.
2013-11-13 Tom Tromey <tromey@redhat.com>
* gdb.multi/multi-arch-exec.exp: Define BASEDIR when compiling.
* gdb.multi/multi-arch-exec.c (main): Use BASEDIR.
A few tests run an inferior that execs some other program. The name
of this exec'd program is compiled in. These tests assume the current
test suite directory layout, but fail in parallel mode.
This patch fixes these tests by letting the .exp files pass in the
directory names at compile time.
2013-11-04 Tom Tromey <tromey@redhat.com>
* gdb.base/foll-exec.c (main): Use BASEDIR.
* gdb.base/foll-exec.exp: Define BASEDIR during compilation.
* gdb.base/foll-vfork.c (main): Use BASEDIR.
* gdb.base/foll-vfork.exp: Define BASEDIR during compilation.
* gdb.multi/bkpt-multi-exec.c (main): Use BASEDIR.
* gdb.multi/bkpt-multi-exec.exp: Define BASEDIR during compilation.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
2012-11-09 Pedro Alves <palves@redhat.com>
* gdbarch.sh (target_gdbarch) <gdbarch.h>: Reimplement as macro.
(get_target_gdbarch) <gdbarch.h>: New function.
(startup_gdbarch) <gdbarch.h>: Declare.
<gdbarch.c> (target_gdbarch): Delete.
<gdbarch.c> (deprecated_target_gdbarch_select_hack): Set the
current inferior's gdbarch.
<gdbarch.c> (get_target_gdbarch): New function.
* inferior.c: Include target-descriptions.h.
(free_inferior): Free target description info.
(add_inferior_with_spaces): Set the inferior's initial
architecture.
(clone_inferior_command): Copy the original inferior's target
description if it was user specified.
(initialize_inferiors): Add comment.
* inferior.h (struct target_desc_info): Forward declare.
(struct inferior) <gdbarch>: New field.
* linux-nat.c: Include target-descriptions.h.
(linux_child_follow_fork): Copy the parent's architecture and
target description to the child.
* target-descriptions.c: Include inferior.h.
(struct target_desc_info): New structure, holding the equivalents
of ...
(target_desc_fetched, current_target_desc)
(target_description_filename): ... these removed globals.
(get_tdesc_info, target_desc_info_from_user_p)
(copy_inferior_target_desc_info, target_desc_info_free): New.
(target_desc_fetched, current_target_desc)
(target_description_filename): Reimplemented as convenience
macros.
(tdesc_filename_cmd_string): New global.
(set_tdesc_filename_cmd): Copy the string manipulated by the "set
tdescs filename ..." commands to the per-inferior equivalent.
(show_tdesc_filename_cmd): Get the value to show from the
per-inferior description filename.
(_initilize_target_descriptions): Change the "set/show tdesc
filename" commands' variable.
* target-descriptions.h (struct target_desc, struct target_desc_info)
(struct inferior): Forward declare.
(target_find_description, target_clear_description)
(target_current_description): Adjust comments.
(copy_inferior_target_desc_info, target_desc_info_free)
(target_desc_info_from_user_p). Declare.
gdb/testsuite/
2012-11-09 Pedro Alves <palves@redhat.com>
* gdb.multi/multi-arch.exp: New.
* gdb.multi/bkpt-multi-exec.exp: Use standard_output_file. Use
build_executable, not prepare_for_testing.
* gdb.multi/base.exp: Use standard_output_file. Use
build_executable, not prepare_for_testing.
Fix watchpoints to be specific for each inferior.
* breakpoint.c (watchpoint_in_thread_scope): Verify also
current_program_space.
* i386-nat.c (i386_inferior_data_cleanup): New.
(i386_inferior_data_get): Replace variable inf_data_local by an
inferior_data call.
(i386_use_watchpoints): Initialize i386_inferior_data.
* linux-nat.c (linux_nat_iterate_watchpoint_lwps): Use INFERIOR_PTID
specific iterate_over_lwps.
gdb/testsuite/
Fix watchpoints to be specific for each inferior.
* gdb.multi/watchpoint-multi.c: New file.
* gdb.multi/watchpoint-multi.exp: New file.
* inferior.c (detach_inferior_command): Use get_number_or_range.
(kill_inferior_command): Ditto.
(remove_inferior_command): Ditto.
(initialize_inferiors): Make command names plural.
Update help strings.
2011-02-25 Michael Snyder <msnyder@vmware.com>
* gdb.texinfo (Inferiors and Programs): Update commands to show
that they can accept multiple arguments.
2011-02-25 Michael Snyder <msnyder@vmware.com>
* gdb.multi/base.exp: Add test for remove-inferiors.
* inferior.c (print_inferior): Accept a string instead of an int
for requested_inferiors, and use get_number_or_range to parse it.
(info_inferiors_command): Pass args string to print_inferior.
(initialize_inferiors): Change help string for info inferiors.
* inferior.h (print_inferior): Export prototype change.
2011-02-25 Michael Snyder <msnyder@vmware.com>
* gdb.multi/base.exp: Add tests for info inferiors with args.
the branch only.
gdb/testsuite/
* gdb.base/foll-vfork.exp: Adjust to spell out "follow-fork".
* gdb.base/foll-exec.exp: Adjust to expect a process id before
"Executing new program".
* gdb.base/foll-fork.exp: Adjust to spell out "follow-fork".
* gdb.base/multi-forks.exp: Ditto. Adjust to the inferior being
left listed after having been killed.
* gdb.base/attach.exp: Adjust to spell out "symbol-file".
* gdb.base/maint.exp: Adjust test.
* Makefile.in (ALL_SUBDIRS): Add gdb.multi.
* gdb.multi/Makefile.in: New.
* gdb.multi/base.exp: New.
* gdb.multi/goodbye.c: New.
* gdb.multi/hangout.c: New.
* gdb.multi/hello.c: New.
* gdb.multi/bkpt-multi-exec.c: New.
* gdb.multi/bkpt-multi-exec.exp: New.
* gdb.multi/crashme.c: New.
Pedro Alves
Joel Brobecker
Tom Tromey
Joel Brobecker
Doug Evans
Yao Qi
Jan Kratochvil
Michael Snyder