This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
The buildbots show that attach-many-short-lived-thread.exp is racy.
But after staring at debug logs and playing with SystemTap scripts for
a (long) while, I figured out that neither GDB, nor the kernel nor the
test's program itself are at fault.
The problem is simply that the testsuite machinery is currently
subject to PID-reuse races. The attach-many-short-lived-threads.c
test program just happens to be much more susceptible to trigger this
race because threads and processes share the same number space on
Linux, and the test spawns many many short lived threads in
succession, thus enlarging the race window a lot.
Part of the problem is that several tests spawn processes with "exec&"
(in order to test the "attach" command) , and then at the end of the
test, to make sure things are cleaned up, issue a 'remote_spawn "kill
-p $testpid"'. Since with tcl's "exec&", tcl itself is responsible
for reaping the process's exit status, when we go kill the process,
testpid may have already exited _and_ its status may have (and often
has) been reaped already. Thus it can happen that another process
meanwhile reuses $testpid, and that "kill" command kills the wrong
process... Frequently, that happens to be
attach-many-short-lived-thread, but this explains other test's races
as well.
In the attach-many-short-lived-threads test, it sometimes manifests
like this:
(gdb) file /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.threads/attach-many-short-lived-threads
Reading symbols from /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.threads/attach-many-short-lived-threads...done.
(gdb) Loaded /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.threads/attach-many-short-lived-threads into /home/pedro/gdb/mygit/build/gdb/testsuite/../../gdb/gdb
attach 5940
Attaching to program: /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.threads/attach-many-short-lived-threads, process 5940
warning: process 5940 is a zombie - the process has already terminated
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ptrace: Operation not permitted.
(gdb) PASS: gdb.threads/attach-many-short-lived-threads.exp: iter 1: attach
info threads
No threads.
(gdb) PASS: gdb.threads/attach-many-short-lived-threads.exp: iter 1: no new threads
set breakpoint always-inserted on
(gdb) PASS: gdb.threads/attach-many-short-lived-threads.exp: iter 1: set breakpoint always-inserted on
Other times the process dies while the test is ongoing (the process is
ptrace-stopped):
(gdb) print again = 1
Cannot access memory at address 0x6020cc
(gdb) FAIL: gdb.threads/attach-many-short-lived-threads.exp: iter 2: reset timer in the inferior
(Recall that on Linux, SIGKILL is not interceptable)
And other times it dies just while we're detaching:
$4 = 319
(gdb) PASS: gdb.threads/attach-many-short-lived-threads.exp: iter 2: print seconds_left
detach
Can't detach Thread 0x7fb13b7de700 (LWP 1842): No such process
(gdb) FAIL: gdb.threads/attach-many-short-lived-threads.exp: iter 2: detach
GDB mishandles the latter (it should ignore ESRCH while detaching just
like when continuing), but that's another story.
The fix here is to change spawn_wait_for_attach to use Expect's
'spawn' command instead of Tcl's 'exec&' to spawn programs, because
with spawn we control when to wait for/reap the process. That allows
killing the process by PID without being subject to pid-reuse races,
because even if the process is already dead, the kernel won't reuse
the process's PID until the zombie is reaped.
The other part of the problem lies in DejaGnu itself, unfortunately.
I have occasionally seen tests (attach-many-short-lived-threads
included, but not only that one) die with a random inexplicable
SIGTERM too, and that too is caused by the same reason, except that in
that case, the rogue SIGTERM is sent from this bit in DejaGnu's remote.exp:
exec sh -c "exec > /dev/null 2>&1 && (kill -2 $pgid || kill -2 $pid) && sleep 5 && (kill $pgid || kill $pid) && sleep 5 && (kill -9 $pgid || kill -9 $pid) &"
...
catch "wait -i $shell_id"
Even if the program exits promptly, that whole cascade of kills
carries on in the background, thus potentially killing the poor
process that manages to reuse $pid...
I sent a fix for that to the DejaGnu list:
http://lists.gnu.org/archive/html/dejagnu/2015-07/msg00000.html
With both patches in place, I haven't seen
attach-many-short-lived-threads.exp fail again.
Tested on x86_64 Fedora 20, native, gdbserver and extended-gdbserver.
gdb/testsuite/ChangeLog:
2015-07-31 Pedro Alves <palves@redhat.com>
* gdb.base/attach-pie-misread.exp: Rename $res to $test_spawn_id.
Use spawn_id_get_pid. Wait for spawn id after eof. Use
kill_wait_spawned_process instead of explicit "kill -9".
* gdb.base/attach-pie-noexec.exp: Adjust to spawn_wait_for_attach
returning a spawn id instead of a pid. Use spawn_id_get_pid and
kill_wait_spawned_process.
* gdb.base/attach-twice.exp: Likewise.
* gdb.base/attach.exp: Likewise.
(do_command_attach_tests): Use gdb_spawn_with_cmdline_opts and
gdb_test_multiple.
* gdb.base/solib-overlap.exp: Adjust to spawn_wait_for_attach
returning a spawn id instead of a pid. Use spawn_id_get_pid and
kill_wait_spawned_process.
* gdb.base/valgrind-infcall.exp: Likewise.
* gdb.multi/multi-attach.exp: Likewise.
* gdb.python/py-prompt.exp: Likewise.
* gdb.python/py-sync-interp.exp: Likewise.
* gdb.server/ext-attach.exp: Likewise.
* gdb.threads/attach-into-signal.exp (corefunc): Use
spawn_wait_for_attach, spawn_id_get_pid and
kill_wait_spawned_process.
* gdb.threads/attach-many-short-lived-threads.exp: Adjust to
spawn_wait_for_attach returning a spawn id instead of a pid. Use
spawn_id_get_pid and kill_wait_spawned_process.
* gdb.threads/attach-stopped.exp (corefunc): Use
spawn_wait_for_attach, spawn_id_get_pid and
kill_wait_spawned_process.
* gdb.base/break-interp.exp: Rename $res to $test_spawn_id.
Use spawn_id_get_pid. Wait for spawn id after eof. Use
kill_wait_spawned_process instead of explicit "kill -9".
* lib/gdb.exp (can_spawn_for_attach): Adjust comment.
(kill_wait_spawned_process, spawn_id_get_pid): New procedures.
(spawn_wait_for_attach): Use spawn instead of exec to spawn
processes. Don't map cygwin/windows pids here. Now returns a
spawn id list.
The previous change to py-prompt.exp made it return without restoring
GDBFLAGS, resulting in breaking the following tests:
$ make check RUNTESTFLAGS="--target_board=native-gdbserver --directory=gdb.python"
...
Running src/gdb/testsuite/gdb.python/py-prompt.exp ...
Running src/gdb/testsuite/gdb.python/py-section-script.exp ...
ERROR: (timeout) GDB never initialized after 10 seconds.
ERROR: no fileid for gdbuild
ERROR: Couldn't send python print ('test') to GDB.
ERROR: no fileid for gdbuild
ERROR: Couldn't send python print (sys.version_info[0]) to GDB.
ERROR: no fileid for gdbuild
ERROR: Couldn't send python print (sys.version_info[1]) to GDB.
ERROR: no fileid for gdbuild
ERROR: no fileid for gdbuild
...
gdb/testsuite/
2015-01-12 Pedro Alves <palves@redhat.com>
* gdb.python/py-prompt.exp: When the board can't spawn for attach,
restore GDBFLAGS before returning.
We already skip "attach" tests if the target board is remote, in
dejagnu's sense, as we use TCL's exec to spawn the program on the
build machine. We should also skip these tests if testing with
"target remote" or other stub-like targets where "attach" doesn't make
sense.
Add a helper procedure that centralizes the checks a test that needs
to spawn a program for testing "attach" and make all test files that
use spawn_wait_for_attach check it.
gdb/testsuite/
2015-01-09 Pedro Alves <palves@redhat.com>
* lib/gdb.exp (can_spawn_for_attach): New procedure.
(spawn_wait_for_attach): Error out if can_spawn_for_attach returns
false.
* gdb.base/attach.exp: Use can_spawn_for_attach instead of
checking whether the target board is remote.
* gdb.multi/multi-attach.exp: Likewise.
* gdb.python/py-sync-interp.exp: Likewise.
* gdb.server/ext-attach.exp: Likewise.
* gdb.python/py-prompt.exp: Use can_spawn_for_attach before the
tests that need to attach, instead of checking whether the target
board is remote at the top of the file.
Several places in the testsuite have a copy of a snippet of code that
spawns a test program, waits a bit, and then does some PID munging for
Cygwin. This is in order to have GDB attach to the spawned program.
This refactors all that to a common procedure.
(multi-attach.exp wants to spawn multiple processes, so this makes the
new procedure's interface work with lists.)
Tested on x86_64 Fedora 20.
gdb/testsuite/ChangeLog:
2014-09-11 Pedro Alves <palves@redhat.com>
* lib/gdb.exp (spawn_wait_for_attach): New procedure.
* gdb.base/attach.exp (do_attach_tests, do_call_attach_tests)
(do_command_attach_tests): Use spawn_wait_for_attach.
* gdb.base/solib-overlap.exp: Likewise.
* gdb.multi/multi-attach.exp: Likewise.
* gdb.python/py-prompt.exp: Likewise.
* gdb.python/py-sync-interp.exp: Likewise.
* gdb.server/ext-attach.exp: Likewise.
This finally makes background execution commands possible by default.
However, in order to do that, there's one last thing we need to do --
we need to separate the MI and target notions of "async". Unlike the
CLI, where the user explicitly requests foreground vs background
execution in the execution command itself (c vs c&), MI chose to treat
"set target-async" specially -- setting it changes the default
behavior of execution commands.
So, we can't simply "set target-async" default to on, as that would
affect MI frontends. Instead we have to make the setting MI-specific,
and teach MI about sync commands on top of an async target.
Because the "target" word in "set target-async" ends up as a potential
source of confusion, the patch adds a "set mi-async" option, and makes
"set target-async" a deprecated alias.
Rather than make the targets always async, this patch introduces a new
"maint set target-async" option so that the GDB developer can control
whether the target is async. This makes it simpler to debug issues
arising only in the synchronous mode; important because sync mode
seems unlikely to go away.
Unlike in previous revisions, "set target-async" does not affect this
new maint parameter. The rationale for this is that then one can
easily run the test suite in the "maint set target-async off" mode and
have tests that enable mi-async fail just like they fail on
non-async-capable targets. This emulation is exactly the point of the
maint option.
I had asked Tom in a previous iteration to split the actual change of
the target async default to a separate patch, but it turns out that
that is quite awkward in this version of the patch, because with MI
async and target async decoupled (unlike in previous versions), if we
don't flip the default at the same time, then just "set target-async
on" alone never actually manages to do anything. It's best to not
have that transitory state in the tree.
Given "set target-async on" now only has effect for MI, the patch goes
through the testsuite removing it from non-MI tests. MI tests are
adjusted to use the new and less confusing "mi-async" spelling.
2014-05-29 Pedro Alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
* NEWS: Mention "maint set target-async", "set mi-async", and that
background execution commands are now always available.
* target.h (target_async_permitted): Update comment.
* target.c (target_async_permitted, target_async_permitted_1):
Default to 1.
(set_target_async_command): Rename to ...
(maint_set_target_async_command): ... this.
(show_target_async_command): Rename to ...
(maint_show_target_async_command): ... this.
(_initialize_target): Adjust.
* infcmd.c (prepare_execution_command): Make extern.
* inferior.h (prepare_execution_command): Declare.
* infrun.c (set_observer_mode): Leave target async alone.
* mi/mi-interp.c (mi_interpreter_init): Install
mi_on_sync_execution_done as sync_execution_done observer.
(mi_on_sync_execution_done): New function.
(mi_execute_command_input_handler): Don't print the prompt if we
just started a synchronous command with an async target.
(mi_on_resume): Check sync_execution before printing prompt.
* mi/mi-main.h (mi_async_p): Declare.
* mi/mi-main.c: Include gdbcmd.h.
(mi_async_p): New function.
(mi_async, mi_async_1): New globals.
(set_mi_async_command, show_mi_async_command, mi_async): New
functions.
(exec_continue): Call prepare_execution_command.
(run_one_inferior, mi_cmd_exec_run, mi_cmd_list_target_features)
(mi_execute_async_cli_command): Use mi_async_p.
(_initialize_mi_main): Install "set mi-async". Make
"target-async" a deprecated alias.
2014-05-29 Pedro Alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
* gdb.texinfo (Non-Stop Mode): Remove "set target-async 1"
from example.
(Asynchronous and non-stop modes): Document '-gdb-set mi-async'.
Mention that target-async is now deprecated.
(Maintenance Commands): Document maint set/show target-async.
2014-05-29 Pedro Alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
* gdb.base/async-shell.exp: Don't enable target-async.
* gdb.base/async.exp
* gdb.base/corefile.exp (corefile_test_attach): Remove 'async'
parameter. Adjust.
(top level): Don't test with "target-async".
* gdb.base/dprintf-non-stop.exp: Don't enable target-async.
* gdb.base/gdb-sigterm.exp: Don't test with "target-async".
* gdb.base/inferior-died.exp: Don't enable target-async.
* gdb.base/interrupt-noterm.exp: Likewise.
* gdb.mi/mi-async.exp: Use "mi-async" instead of "target-async".
* gdb.mi/mi-nonstop-exit.exp: Likewise.
* gdb.mi/mi-nonstop.exp: Likewise.
* gdb.mi/mi-ns-stale-regcache.exp: Likewise.
* gdb.mi/mi-nsintrall.exp: Likewise.
* gdb.mi/mi-nsmoribund.exp: Likewise.
* gdb.mi/mi-nsthrexec.exp: Likewise.
* gdb.mi/mi-watch-nonstop.exp: Likewise.
* gdb.multi/watchpoint-multi.exp: Adjust comment.
* gdb.python/py-evsignal.exp: Don't enable target-async.
* gdb.python/py-evthreads.exp: Likewise.
* gdb.python/py-prompt.exp: Likewise.
* gdb.reverse/break-precsave.exp: Don't test with "target-async".
* gdb.server/solib-list.exp: Don't enable target-async.
* gdb.threads/thread-specific-bp.exp: Likewise.
* lib/mi-support.exp: Adjust to use mi-async.
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.
* gdb.base/charset.exp: Change print syntax for Python 3
compatibility.
* gdb.python/py-block.exp: Ditto.
* gdb.python/py-breakpoint.exp: Ditto.
* gdb.python/py-cmd.exp: Ditto.
* gdb.python/py-events.py: Ditto.
* gdb.python/py-finish-breakpoint.py: Ditto.
* gdb.python/py-finish-breakpoint2.exp: Ditto.
* gdb.python/py-finish-breakpoint2.py: Ditto.
* gdb.python/py-frame-inline.exp: Ditto.
* gdb.python/py-frame.exp: Ditto.
* gdb.python/py-infthread.exp: Ditto.
* gdb.python/py-objfile.exp: Ditto.
* gdb.python/py-parameter.exp: Ditto.
* gdb.python/py-progspace.exp: Ditto.
* gdb.python/py-prompt.exp: Ditto.
* gdb.python/py-symbol.exp: Ditto.
* gdb.python/py-symtab.exp: Ditto.
* gdb.python/py-template.exp: Ditto.
* gdb.python/py-value-cc.exp: Ditto.
* gdb.python/python.exp: Ditto.
* gdb.python/source2.py: Ditto.
* gdb.python/lib-types.exp: Change print syntax for Python 3
compatibility.
Use sorted() function rather than sort() method.
Accept either int or long values for enum values.
* gdb.python/py-events.exp: Use exec(open(...).read()) instead of
execfile for Python 3 compatibility.
* gdb.python/py-evsignal.exp: Ditto.
* gdb.python/py-evthreads.exp: Ditto.
* gdb.python/py-mi.exp: Ditto.
* gdb.python/py-pp-maint.exp: Ditto.
* gdb.python/py-prettyprint.exp: Ditto.
* gdb.python/py-finish-breakpoint.exp: Change print syntax for
Python 3 compatibility.
Skip tests for Python 2.4.
* gdb.python/py-inferior.exp: Change print syntax for
Python 3 compatibility.
Use byte string rather than character string in memory write test
if Python 3.
* gdb.python/py-pp-maint.py: Change class declarations to "new
class" syntax.
* gdb.python/py-prettyprint.py: Change iterator class to generator
function for Python 3 compatibility.
Make all classes "new style".
Fix indentation issue and stray semicolon.
* gdb.python/py-shared.expChange print syntax for Python 3
compatibility.
Define "long" if Python 3.
* gdb.python/py-type.exp: Change print syntax for Python 3
compatibility.
Accept either int or long values for enum values.
* gdb.python/py-value.exp: Change print syntax for Python 3
compatibility.
Skip "long" and "unicode" tests if Python 3.
Accept either "type" or "class" in type checks.
* lib/gdb.exp (gdb_py_is_py3k): New flag set if Python 3.
(gdb_py_is_py24): New flag set if Python 2.4 or 2.5.
prepare_for_testing.
* gdb.python/py-block.exp: Use standard_testfile.
* gdb.python/py-breakpoint.exp: Use standard_testfile.
* gdb.python/py-events.exp: Use standard_testfile,
standard_output_file.
* gdb.python/py-evsignal.exp: Use standard_testfile.
* gdb.python/py-evethreads.exp: Use standard_testfile.
* gdb.python/py-explore-cc.exp: Use standard_testfile.
* gdb.python/py-explore.exp: Use standard_testfile.
* gdb.python/py-finish-breakpoint.exp: Use standard_testfile,
standard_output_file.
* gdb.python/py-finish-breakpoint2.exp: Use standard_testfile,
prepare_for_testing.
* gdb.python/py-frame-inline.exp: Use standard_testfile.
* gdb.python/py-frame.exp: Use standard_testfile.
* gdb.python/py-inferior.exp: Use standard_testfile.
* gdb.python/py-infthread.exp: Use standard_testfile.
* gdb.python/py-mi.exp: Use standard_testfile.
* gdb.python/py-objfile-script.exp: Use standard_testfile,
build_executable.
* gdb.python/py-objfile.exp: Use standard_testfile.
* gdb.python/py-pp-maint.exp: Use standard_testfile,
prepare_for_testing.
* gdb.python/py-prettyprint.exp: Use standard_testfile.
* gdb.python/py-progspace.exp: Use standard_testfile,
build_executable.
* gdb.python/py-prompt.exp: Use standard_testfile,
build_executable.
* gdb.python/py-section-script.exp: Use standard_testfile,
build_executable.
* gdb.python/py-shared.exp: Use standard_testfile,
standard_output_file, clean_restart.
* gdb.python/py-symbol.exp: Use standard_output_file,
prepare_for_testing.
* gdb.python/py-symtab.exp: Use standard_output_file,
prepare_for_testing
* gdb.python/py-template.exp: Use standard_testfile.
* gdb.python/py-type.exp: Use standard_testfile.
* gdb.python/py-value-cc.exp: Use standard_testfile.
* gdb.python/py-value.exp: Use standard_testfile.
* gdb.python/python.exp: Use standard_testfile, build_executable.
* event-top.c (cli_command_loop): Replace readline setup with
direct call to display_gdb_prompt.
(display_gdb_prompt): Do not call observer mechanism during
synchronous execution.
testsuite:
* lib/prompt.exp: New file for testing the first prompt.
* gdb.python/py-prompt.exp: Ditto.
* gdb.python/py-prompt.c: Ditto (copy of ext-attach.c).
Joel Brobecker