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.
"single-process" and "multi-process" are used in the test message of
process-dies-while-detaching.exp, but they are misplaced due to
set mode [expr {$multi_process ? "single-process" : "multi-process"}]
This patch is to swap them.
gdb/testsuite:
2016-08-01 Yao Qi <yao.qi@linaro.org>
* gdb.threads/process-dies-while-detaching.exp (do_test): Set
variable mode to "multi-process" if $multi_process is 1, otherwise
set it to "single-process".
PR python/20190 arose from an exception I noticed when trying to use
the Python unwinder for Spider Monkey in Firefox.
The problem is that the unwinder wants to examine the value of a
thread-local variable. However, sympy_value rejects this because
symbol_read_needs_frame returns true for a TLS variable.
This problem arose once before, though in a different context:
https://sourceware.org/bugzilla/show_bug.cgi?id=11803
At the time Pedro and Daniel pointed out a simpler way to fix that bug
(see links in 20190 if you are interested); but for this new bug I
couldn't think of a similar fix and ended up implementing Daniel's
other suggestion:
https://sourceware.org/ml/gdb-patches/2010-07/msg00393.html
That is, this patch makes it possible to detect whether a symbol needs
a specific frame, or whether it just needs the inferior to have
registers.
Built and regtested on x86-64 Fedora 24.
2016-07-26 Tom Tromey <tom@tromey.com>
* symtab.c (register_symbol_computed_impl): Update.
PR python/20190:
* value.h (symbol_read_needs): Declare.
(symbol_read_needs_frame): Add comment.
* symtab.h (struct symbol_computed_ops) <read_variable>: Update
comment.
<get_symbol_read_needs>: Rename. Change return type.
* findvar.c (symbol_read_needs): New function.
(symbol_read_needs_frame): Rewrite.
(default_read_var_value): Use symbol_read_needs.
* dwarf2loc.c (struct symbol_needs_baton): Rename.
<needs>: Renamed from needs_frame. Changed type.
(needs_frame_read_addr_from_reg, symbol_needs_get_reg_value)
(symbol_needs_read_mem, symbol_needs_frame_base)
(symbol_needs_frame_cfa, symbol_needs_tls_address)
(symbol_needs_dwarf_call): Rename.
(needs_dwarf_reg_entry_value): Update.
(symbol_needs_ctx_funcs, dwarf2_loc_desc_get_symbol_read_needs):
Rename and update.
(locexpr_get_symbol_read_needs, loclist_symbol_needs): Likewise.
(dwarf2_locexpr_funcs, dwarf2_loclist_funcs): Update.
* defs.h (enum symbol_needs_kind): New.
2016-07-26 Tom Tromey <tom@tromey.com>
PR python/20190:
* gdb.threads/tls.exp (check_thread_local): Add python symbol
test.
This commit fixes detaching on Linux when some thread exits the whole
thread group (process) just while we're detaching.
On Linux, a ptracer must detach from each LWP individually, with
PTRACE_DETACH. Since PTRACE_DETACH sets the thread running free, if
one of the already-detached threads causes the whole thread group to
exit (e.g., simply calls exit), the kernel force-kills the other
threads in the group, making them zombie, just as we're still
detaching them. Since PTRACE_DETACH against a zombie thread fails
with ESRCH, and gdb/gdbserver are not expecting this, the detach fails
with an error like: "Can't detach process: No such process.".
This patch detects this detach failure as normal, and instead of
erroring out, reaps the now-dead thread.
New test included, that exercises several different scenarios that
cause GDB/GDBserver to error out when it should not.
Tested on x86-64 GNU/Linux with {unix, native-gdbserver,
native-extended-gdbserver}
Note: without the previous fix, the "single-process + continue"
variant of the new test would fail with:
(gdb) PASS: gdb.threads/process-dies-while-detaching.exp: single-process: continue: watchpoint: switch to parent
continue
Continuing.
Warning:
Could not insert hardware watchpoint 3.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
(gdb) FAIL: gdb.threads/process-dies-while-detaching.exp: single-process: continue: watchpoint: continue
gdb/gdbserver/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* linux-low.c: Change interface to take the target lwp_info
pointer directly and return void. Handle detaching from a zombie
thread.
(linux_detach_lwp_callback): New function.
(linux_detach): Detach from the leader thread after detaching from
the clone threads.
gdb/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* inf-ptrace.c (inf_ptrace_detach_success): New function, factored
out from ...
(inf_ptrace_detach): ... here.
* inf-ptrace.h (inf_ptrace_detach_success): New declaration.
* linux-nat.c (get_pending_status): Rename to ...
(get_detach_signal): ... this, and return a host signal instead of
filling in a wait status.
(detach_one_lwp): New function, factored out from detach_callback
and adjusted to handle detaching from a zombie thread.
(detach_callback): Skip the leader thread.
(linux_nat_detach): No longer defer to inf_ptrace_detach to detach
the leader thread, nor build a signal string to pass down.
Instead, use target_announce_detach, detach_one_lwp and
inf_ptrace_detach_success.
gdb/testsuite/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* gdb.threads/process-dies-while-detaching.c: New file.
* gdb.threads/process-dies-while-detaching.exp: New file.
If a target does not support making function calls from GDB then in a
number of test files, we currently report an XFAIL and skip some, or all
of the tests. This commit changes the XFAIL to an UNSUPPORTED as this
seems more appropriate in these cases.
Some of the tests used bug ID 2416 to be reported in the XFAIL. In the
current GDB bugzilla bug 2416 has nothing to do with calling target
functions from GDB.
gdb/testsuite/ChangeLog:
* gdb.base/call-ar-st.exp: Report unsupported rather than xfail
for unsupported target features.
* gdb.base/call-rt-st.exp: Likewise.
* gdb.base/call-sc.exp: Likewise.
* gdb.base/call-signal-resume.exp: Likewise.
* gdb.base/call-strs.exp: Likewise.
* gdb.base/callexit.exp: Likewise.
* gdb.base/callfuncs.exp: Likewise.
* gdb.base/nodebug.exp: Likewise.
* gdb.base/printcmds.exp: Likewise.
* gdb.base/ptype.exp: Likewise.
* gdb.base/structs.exp: Likewise.
* gdb.base/unwindonsignal.exp: Likewise.
* gdb.cp/gdb2495.exp: Likewise.
* gdb.cp/templates.exp: Likewise.
* gdb.cp/virtfunc.exp: Likewise.
* gdb.threads/hand-call-in-threads.exp: Likewise.
* gdb.threads/interrupted-hand-call.exp: Likewise.
* gdb.threads/thread-unwindonsignal.exp: Likewise.
If the testsuite is run with a DejaGnu version that predates the fix
from last year:
[PATCH] DejaGnu kills the wrong process due to PID-reuse races
http://lists.gnu.org/archive/html/dejagnu/2015-07/msg00005.html
... gdb.threads/attach-many-short-lived-threads.exp fails randomly,
often. Other tests randomly fail due to that issue too, but this one
is _much_ more exposed.
DejaGnu 1.6 was released meanwhile, which includes that DejaGnu fix,
and also some distros backported the fix too.
So skip the test when run with older/broken DejaGnus.
gdb/testsuite/ChangeLog:
2016-05-27 Pedro Alves <palves@redhat.com>
* gdb.threads/attach-many-short-lived-threads.exp (bad_dejagnu):
New procedure.
(top level): Call it, and bail out of DejaGnu is known to be bad.
When GDB attaches to a process, it looks at the /proc/PID/task/ dir
for all clone threads of that process, and attaches to each of them.
Usually, if there is more than one clone thread, it means the program
is multi threaded and linked with pthreads. Thus when GDB soon after
attaching finds and loads a libthread_db matching the process, it'll
add a thread to the thread list for each of the initially found
lower-level LWPs.
If, however, GDB fails to find/load a matching libthread_db, nothing
is adding the LWPs to the thread list. And because of that, "detach"
hits an internal error:
(gdb) PASS: gdb.threads/clone-attach-detach.exp: fg attach 1: attach
info threads
Id Target Id Frame
* 1 LWP 6891 "clone-attach-de" 0x00007f87e5fd0790 in __nanosleep_nocancel () at ../sysdeps/unix/syscall-template.S:84
(gdb) FAIL: gdb.threads/clone-attach-detach.exp: fg attach 1: info threads shows two LWPs
detach
.../src/gdb/thread.c:1010: internal-error: is_executing: Assertion `tp' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
FAIL: gdb.threads/clone-attach-detach.exp: fg attach 1: detach (GDB internal error)
From here:
...
#8 0x00000000007ba7cc in internal_error (file=0x98ea68 ".../src/gdb/thread.c", line=1010, fmt=0x98ea30 "%s: Assertion `%s' failed.")
at .../src/gdb/common/errors.c:55
#9 0x000000000064bb83 in is_executing (ptid=...) at .../src/gdb/thread.c:1010
#10 0x00000000004c23bb in get_pending_status (lp=0x12c5cc0, status=0x7fffffffdc0c) at .../src/gdb/linux-nat.c:1235
#11 0x00000000004c2738 in detach_callback (lp=0x12c5cc0, data=0x0) at .../src/gdb/linux-nat.c:1317
#12 0x00000000004c1a2a in iterate_over_lwps (filter=..., callback=0x4c2599 <detach_callback>, data=0x0) at .../src/gdb/linux-nat.c:899
#13 0x00000000004c295c in linux_nat_detach (ops=0xe7bd30, args=0x0, from_tty=1) at .../src/gdb/linux-nat.c:1358
#14 0x000000000068284d in delegate_detach (self=0xe7bd30, arg1=0x0, arg2=1) at .../src/gdb/target-delegates.c:34
#15 0x0000000000694141 in target_detach (args=0x0, from_tty=1) at .../src/gdb/target.c:2241
#16 0x0000000000630582 in detach_command (args=0x0, from_tty=1) at .../src/gdb/infcmd.c:2975
...
Tested on x86-64 Fedora 23. Also confirmed the test passes against
gdbserver with "maint set target-non-stop".
gdb/ChangeLog:
2016-05-24 Pedro Alves <palves@redhat.com>
PR gdb/19828
* linux-nat.c (attach_proc_task_lwp_callback): Mark the lwp
resumed, and add the thread to GDB's thread list.
testsuite/ChangeLog:
2016-05-24 Pedro Alves <palves@redhat.com>
PR gdb/19828
* gdb.threads/clone-attach-detach.c: New file.
* gdb.threads/clone-attach-detach.exp: New file.
Following, commit
6e774b13c3 Make ftrace tests work with remote targets
the test gdb.threads/dlopen-libpthread.exp started to fail with:
ERROR: error copying "/home/emaisin/build/binutils-gdb/gdb/testsuite/gdb.threads/dlopen-libpthread.so": no such file or directory
This is because the library path is not computed using
standard_output_file, so we try to gdb_load_shlibs an unexisting file.
gdb/testsuite/ChangeLog:
* gdb.threads/dlopen-libpthread.exp: Set binfile_lib using
standard_output_file. Remove unused binfile variable.
This patch addresses "fork:Interrupted system call" (or wait:) failures
in gdb.threads/forking-threads-plus-breakpoint.exp.
The test program spawns ten threads, each of which do ten fork/waitpid
sequences. The cause of the problem was that when one of the fork
children exited before the corresponding fork parent could initiate its
waitpid for that child, a SIGCHLD and/or SIGSTOP was delivered and
interrupted a fork or waitpid in another thread.
The fix was to wrap the system calls in a loop to retry the call if
it was interrupted, like:
do
{
pid = fork ();
}
while (pid == -1 && errno == EINTR);
Since this is a Linux-only test I figure it is OK to use errno and EINTR.
I tried a number of alternative fixes using SIG_IGN, SA_RESTART,
pthread_sigblock, and bsd_signal, but none of these worked as well.
Tested on Nios II Linux target with x86 Linux host.
gdb/testsuite/ChangeLog:
2016-03-16 Don Breazeal <donb@codesourcery.com>
* gdb.threads/forking-threads-plus-breakpoint.c (thread_forks):
Retry fork and waitpid on interrupted system call errors.
* gdb.threads/forking-threads-plus-breakpoint.exp: (do_test):
Use with_timeout_factor to increase timeout to 90.
These tests should have been adjusted by f303dbd60d (Fix PR
threads/19422 - show which thread caused stop), but clearly I had
missed grepping for potential-fail cases.
gdb/testsuite/ChangeLog
2016-03-09 Pedro Alves <palves@redhat.com>
* gdb.threads/attach-into-signal.exp: Adjust to "Program received
signal" -> "Thread NN received signal" output change.
* gdb.threads/ia64-sigill.exp: Likewise.
* gdb.threads/linux-dp.exp: Likewise.
* gdb.threads/manythreads.exp: Likewise.
* gdb.threads/pending-step.exp: Likewise.
* gdb.threads/print-threads.exp: Likewise.
* gdb.threads/sigstep-threads.exp: Likewise.
* gdb.threads/staticthreads.exp: Likewise.
* gdb.threads/tls.exp: Likewise.
This testcase currently fails to compile on Fedora 23:
.../src/gdb/testsuite/gdb.threads/watchpoint-fork-mt.c: In function 'start':
.../src/gdb/testsuite/gdb.threads/watchpoint-fork-mt.c:70:11: warning: implicit declaration of function 'pthread_yield' [-Wimplicit-function-declaration]
i = pthread_yield ();
^
.../src/gdb/testsuite/gdb.threads/watchpoint-fork-child.c: In function 'forkoff':
.../src/gdb/testsuite/gdb.threads/watchpoint-fork-child.c:114:8: warning: implicit declaration of function 'pthread_yield' [-Wimplicit-function-declaratio
n]
i = pthread_yield ();
^
/tmp/ccUkNIsI.o: In function `start':
.../src/gdb/testsuite/gdb.threads/watchpoint-fork-mt.c:70: undefined reference to `pthread_yield'
(...)
collect2: error: ld returned 1 exit status
UNSUPPORTED: gdb.threads/watchpoint-fork.exp: child: multithreaded: Couldn't compile watchpoint-fork-child.c: unrecognized error
UNTESTED: gdb.threads/watchpoint-fork.exp: child: multithreaded: watchpoint-fork.exp
testcase .../src/gdb/testsuite/gdb.threads/watchpoint-fork.exp completed i
The glibc manual says, on _GNU_SOURCE:
"You should define these macros by using ‘#define’ preprocessor
directives at the top of your source code files. These directives must
come before any #include of a system header file."
I instead put it in the header all the .c files of the testcase must
include anyway.
gdb/testsuite/ChangeLog:
2016-03-01 Pedro Alves <palves@redhat.com>
* gdb.threads/watchpoint-fork-child.c: Include "watchpoint-fork.h"
before anything else.
* gdb.threads/watchpoint-fork-mt.c: Likewise. Don't define
_GNU_SOURCE here.
* gdb.threads/watchpoint-fork-st.c: Include "watchpoint-fork.h"
before anything else.
* gdb.threads/watchpoint-fork.h: Define _GNU_SOURCE.
Proc do_test in forking-threads-plus-breakpoint.exp has an argument
cond_bp_target, but the test doesn't use it to set
"breakpoint condition-evaluation", which is an oversight in the test.
This patch fixes it by setting "breakpoint condition-evaluation" per
$cond_bp_target.
gdb/testsuite:
2016-02-18 Yao Qi <yao.qi@linaro.org>
* gdb.threads/forking-threads-plus-breakpoint.exp (do_test):
Set "set breakpoint condition-evaluation" per $cond_bp_target.
This patch fixes an internal error that occurs in
gdb.threads/forking-threads-plus-breakpoint.exp:
/blah/binutils-gdb/gdb/target.c:2723: internal-error: Can't determine the
current address space of thread Thread 3170.3170
In default_thread_address_space, find_inferior_ptid couldn't find 3170.3170
because it had been overwritten in inferior_appeared, called as follows:
inferior_appeared
remote_add_inferior
remote_notice_new_inferior
remote_update_thread_list
The cause of the problem was the following sequence of events:
* GDB knows only about the main thread
* the first fork event is reported to GDB, saved as pending_event
* qXfer:threads:read gets the threads from the remote.
remove_new_fork_children id's the fork child from the pending event
and removes it from the list reported to GDB. All the rest of the
threads, including the fork parent, are added to the GDB thread list.
* GDB stops all the threads. All the stop events are pushed onto the
stop reply queue behind the pending fork event. The fork waitstatus
is saved in the fork parent thread's pending status field
thread_info.suspend.
* remote_wait_ns calls queued_stop_reply and process_stop_reply to
remove the fork event from the front of the stop reply queue and save
event information in the thread_info structure for the fork parent
thread. Unfortunately, none of the information saved in this way is
the fork-specific information.
* A subsequent qXfer:threads:read packet gets the thread list including
the fork parent and fork child. remove_new_fork_children checks the
thread list to see if there is a fork parent, doesn't find one, checks
the stop reply queue for a pending fork event, doesn't find one, and
allows the fork child thread to be reported to GDB before the fork
event has been handled. remote_update_thread_list calls
remote_notice_new_thread and overwrites the current (main) thread in
inferior_appeared.
So the fork event has been reported out of target_wait but it was left
pending on the infrun side (infrun.c:save_waitstatus). IOW, the fork
event hasn't been processed by handle_inferior_event yet, so it hasn't
made it to tp->pending_follow yet.
The fix is to check thread_info.suspend along with the
thread_info.pending_follow in remote.c:remove_new_fork_children, to
prevent premature reporting of the fork child thread creation.
gdb/ChangeLog:
PR remote/19496
* remote.c (remove_new_fork_children): Check for pending
fork status in thread_info.suspend.
gdb/testsuite/ChangeLog:
PR remote/19496
* gdb.threads/forking-threads-plus-breakpoint.exp (do_test):
Remove kfail for PR remote/19496.
When running tests in parallel, each test puts its generated files in a
different directory, under "outputs". I think it would be nice if it
was always the case, as it would isolate the test cases a bit more. An
artifact created by a test wouldn't get overwritten by another test.
Also, it makes it easier to clean up. A lot of executables are left all
over the place because their names do not appear in gdb.*/Makefile. If
everything is in "outputs", then we just have to delete that directory
(which we already do).
At the same time it makes the gdb.foo directories and their Makefiles
useless in the build directory, since they are pretty much only used for
cleaning.
What do you think?
gdb/testsuite/ChangeLog:
* Makefile.in (ALL_SUBDIRS): Remove.
(clean mostlyclean): Do not recurse in ALL_SUBDIRS.
(distclean maintainer-clean realclean): Likewise.
* configure.ac (AC_OUTPUT): Remove gdb.*/Makefile.
* configure: Regenerate.
* gdb.ada/Makefile.in: Delete.
* gdb.arch/Makefile.in: Likewise.
* gdb.asm/Makefile.in: Likewise.
* gdb.base/Makefile.in: Likewise.
* gdb.btrace/Makefile.in: Likewise.
* gdb.cell/Makefile.in: Likewise.
* gdb.compile/Makefile.in: Likewise.
* gdb.cp/Makefile.in: Likewise.
* gdb.disasm/Makefile.in: Likewise.
* gdb.dlang/Makefile.in: Likewise.
* gdb.dwarf2/Makefile.in: Likewise.
* gdb.fortran/Makefile.in: Likewise.
* gdb.gdb/Makefile.in: Likewise.
* gdb.go/Makefile.in: Likewise.
* gdb.guile/Makefile.in: Likewise.
* gdb.java/Makefile.in: Likewise.
* gdb.linespec/Makefile.in: Likewise.
* gdb.mi/Makefile.in: Likewise.
* gdb.modula2/Makefile.in: Likewise.
* gdb.multi/Makefile.in: Likewise.
* gdb.objc/Makefile.in: Likewise.
* gdb.opencl/Makefile.in: Likewise.
* gdb.opt/Makefile.in: Likewise.
* gdb.pascal/Makefile.in: Likewise.
* gdb.perf/Makefile.in: Likewise.
* gdb.python/Makefile.in: Likewise.
* gdb.reverse/Makefile.in: Likewise.
* gdb.server/Makefile.in: Likewise.
* gdb.stabs/Makefile.in: Likewise.
* gdb.threads/Makefile.in: Likewise.
* gdb.trace/Makefile.in: Likewise.
* gdb.xml/Makefile.in: Likewise.
* lib/gdb.exp (make_gdb_parallel_path): Add check for
GDB_PARALLEL.
(standard_output_file): Remove check for GDB_PARALLEL, always
return path in outputs/$subdir/$testname.
This exposes the internal error Don mentioned in PR19496:
(1) internal error -- gdb/target.c:2713: internal-error: Can't determine the current address space of thread
More analysis here:
https://sourceware.org/ml/gdb-patches/2016-01/msg00685.html
The (now kfailed) internal error looks like:
continue &
Continuing.
(gdb) PASS: gdb.threads/forking-threads-plus-breakpoint.exp: cond_bp_target=1: detach_on_fork=on: displaced=off: continue &
[New Thread 2846.2847]
(...)
[New Thread 2867.2867]
/home/pedro/gdb/mygit/src/gdb/target.c:2723: internal-error: Can't determine the current address space of thread Thread 2846.2846
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) KFAIL: gdb.threads/forking-threads-plus-breakpoint.exp: cond_bp_target=1: detach_on_fork=on: displaced=off: inferior 1 exited (GDB internal error) (PRMS: remote/19496)
Resyncing due to internal error.
gdb/testsuite/ChangeLog:
2016-02-01 Pedro Alves <palves@redhat.com>
PR remote/19496
* gdb.threads/forking-threads-plus-breakpoint.exp
(displaced_stepping_supported): New global.
(probe_displaced_stepping_support): New procedure.
(do_test): Add 'displaced' parameter, and use it.
(top level): Check for displaced stepping support. Add displaced
stepping on/off testing axis.
This commit changes GDB like this:
- Program received signal SIGINT, Interrupt.
+ Thread 1 "main" received signal SIGINT, Interrupt.
- Breakpoint 1 at 0x40087a: file threads.c, line 87.
+ Thread 3 "bar" hit Breakpoint 1 at 0x40087a: file threads.c, line 87.
... once the program goes multi-threaded. Until GDB sees a second
thread spawn, the output is still the same as before, per the
discussion back in 2012:
https://www.sourceware.org/ml/gdb/2012-11/msg00010.html
This helps non-stop mode, where you can't easily tell which thread hit
a breakpoint or received a signal:
(gdb) info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 19362) "main" (running)
2 Thread 0x7ffff7fc0700 (LWP 19366) "foo" (running)
3 Thread 0x7ffff77bf700 (LWP 19367) "bar" (running)
(gdb)
Program received signal SIGUSR1, User defined signal 1.
0x0000003616a09237 in pthread_join (threadid=140737353877248, thread_return=0x7fffffffd5b8) at pthread_join.c:92
92 lll_wait_tid (pd->tid);
(gdb) b threads.c:87
Breakpoint 1 at 0x40087a: file threads.c, line 87.
(gdb)
Breakpoint 1, thread_function1 (arg=0x1) at threads.c:87
87 usleep (1); /* Loop increment. */
The best the user can do is run "info threads" and try to figure
things out.
It actually also affects all-stop mode, in case of "handle SIG print
nostop":
...
Program received signal SIGUSR1, User defined signal 1.
Program received signal SIGUSR1, User defined signal 1.
Program received signal SIGUSR1, User defined signal 1.
Program received signal SIGUSR1, User defined signal 1.
...
The above doesn't give any clue that these were different threads
getting the SIGUSR1 signal.
I initially thought of lowercasing "breakpoint" in
"Thread 3 hit Breakpoint 1"
but then after trying it I realized that leaving "Breakpoint"
uppercase helps the eye quickly find the relevant information. It's
also easier to implement not showing anything about threads until the
program goes multi-threaded this way.
Here's a larger example session in non-stop mode:
(gdb) c -a&
Continuing.
(gdb) interrupt -a
(gdb)
Thread 1 "main" stopped.
0x0000003616a09237 in pthread_join (threadid=140737353877248, thread_return=0x7fffffffd5b8) at pthread_join.c:92
92 lll_wait_tid (pd->tid);
Thread 2 "foo" stopped.
0x0000003615ebc6ed in nanosleep () at ../sysdeps/unix/syscall-template.S:81
81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
Thread 3 "bar" stopped.
0x0000003615ebc6ed in nanosleep () at ../sysdeps/unix/syscall-template.S:81
81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
b threads.c:87
Breakpoint 4 at 0x40087a: file threads.c, line 87.
(gdb) b threads.c:67
Breakpoint 5 at 0x400811: file threads.c, line 67.
(gdb) c -a&
Continuing.
(gdb)
Thread 3 "bar" hit Breakpoint 4, thread_function1 (arg=0x1) at threads.c:87
87 usleep (1); /* Loop increment. */
Thread 2 "foo" hit Breakpoint 5, thread_function0 (arg=0x0) at threads.c:68
68 (*myp) ++;
info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 31957) "main" (running)
2 Thread 0x7ffff7fc0700 (LWP 31961) "foo" thread_function0 (arg=0x0) at threads.c:68
3 Thread 0x7ffff77bf700 (LWP 31962) "bar" thread_function1 (arg=0x1) at threads.c:87
(gdb) shell kill -SIGINT 31957
(gdb)
Thread 1 "main" received signal SIGINT, Interrupt.
0x0000003616a09237 in pthread_join (threadid=140737353877248, thread_return=0x7fffffffd5b8) at pthread_join.c:92
92 lll_wait_tid (pd->tid);
info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 31957) "main" 0x0000003616a09237 in pthread_join (threadid=140737353877248, thread_return=0x7fffffffd5b8) at pthread_join.c:92
2 Thread 0x7ffff7fc0700 (LWP 31961) "foo" thread_function0 (arg=0x0) at threads.c:68
3 Thread 0x7ffff77bf700 (LWP 31962) "bar" thread_function1 (arg=0x1) at threads.c:87
(gdb) t 2
[Switching to thread 2, Thread 0x7ffff7fc0700 (LWP 31961)]
#0 thread_function0 (arg=0x0) at threads.c:68
68 (*myp) ++;
(gdb) catch syscall
Catchpoint 6 (any syscall)
(gdb) c&
Continuing.
(gdb)
Thread 2 "foo" hit Catchpoint 6 (call to syscall nanosleep), 0x0000003615ebc6ed in nanosleep () at ../sysdeps/unix/syscall-template.S:81
81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
I'll work on documentation next if this looks agreeable.
This patch applies on top of the star wildcards thread IDs series:
https://sourceware.org/ml/gdb-patches/2016-01/msg00291.html
For convenience, I've pushed this to the
users/palves/show-which-thread-caused-stop branch.
gdb/doc/ChangeLog:
2016-01-18 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Threads): Mention that GDB displays the ID and name
of the thread that hit a breakpoint or received a signal.
gdb/ChangeLog:
2016-01-18 Pedro Alves <palves@redhat.com>
* NEWS: Mention that GDB now displays the ID and name of the
thread that hit a breakpoint or received a signal.
* break-catch-sig.c (signal_catchpoint_print_it): Use
maybe_print_thread_hit_breakpoint.
* break-catch-syscall.c (print_it_catch_syscall): Likewise.
* break-catch-throw.c (print_it_exception_catchpoint): Likewise.
* breakpoint.c (maybe_print_thread_hit_breakpoint): New function.
(print_it_catch_fork, print_it_catch_vfork, print_it_catch_solib)
(print_it_catch_exec, print_it_ranged_breakpoint)
(print_it_watchpoint, print_it_masked_watchpoint, bkpt_print_it):
Use maybe_print_thread_hit_breakpoint.
* breakpoint.h (maybe_print_thread_hit_breakpoint): Declare.
* gdbthread.h (show_thread_that_caused_stop): Declare.
* infrun.c (print_signal_received_reason): Print which thread
received signal.
* thread.c (show_thread_that_caused_stop): New function.
gdb/testsuite/ChangeLog:
2016-01-18 Pedro Alves <palves@redhat.com>
* gdb.base/async-shell.exp: Adjust expected output.
* gdb.base/dprintf-non-stop.exp: Adjust expected output.
* gdb.base/siginfo-thread.exp: Adjust expected output.
* gdb.base/watchpoint-hw-hit-once.exp: Adjust expected output.
* gdb.java/jnpe.exp: Adjust expected output.
* gdb.threads/clone-new-thread-event.exp: Adjust expected output.
* gdb.threads/continue-pending-status.exp: Adjust expected output.
* gdb.threads/leader-exit.exp: Adjust expected output.
* gdb.threads/manythreads.exp: Adjust expected output.
* gdb.threads/pthreads.exp: Adjust expected output.
* gdb.threads/schedlock.exp: Adjust expected output.
* gdb.threads/siginfo-threads.exp: Adjust expected output.
* gdb.threads/signal-command-multiple-signals-pending.exp: Adjust
expected output.
* gdb.threads/signal-delivered-right-thread.exp: Adjust expected
output.
* gdb.threads/sigthread.exp: Adjust expected output.
* gdb.threads/watchpoint-fork.exp: Adjust expected output.
This commit adds a new $_gthread convenience variable, that is like
$_thread, but holds the current thread's global thread id.
gdb/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
* NEWS: Mention $_gthread.
* gdbthread.h (struct thread_info) <global_num>: Mention
$_gthread.
* thread.c (thread_num_make_value_helper): New function.
(thread_id_make_value): Delete.
(thread_id_per_inf_num_make_value, global_thread_id_make_value):
New.
(thread_funcs): Adjust.
(gthread_funcs): New.
(_initialize_thread): Register $_gthread variable.
gdb/testsuite/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
* gdb.base/default.exp: Expect $_gthread as well.
* gdb.multi/tids.exp: Test $_gthread.
* gdb.threads/thread-specific.exp: Test $_gthread.
gdb/doc/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Threads): Document the $_gthread convenience
variable.
(Convenience Vars): Likewise.
This commit changes GDB to track thread numbers per-inferior. Then,
if you're debugging multiple inferiors, GDB displays
"inferior-num.thread-num" instead of just "thread-num" whenever it
needs to display a thread:
(gdb) info inferiors
Num Description Executable
1 process 6022 /home/pedro/gdb/tests/threads
* 2 process 6037 /home/pedro/gdb/tests/threads
(gdb) info threads
Id Target Id Frame
1.1 Thread 0x7ffff7fc2740 (LWP 6022) "threads" (running)
1.2 Thread 0x7ffff77c0700 (LWP 6028) "threads" (running)
1.3 Thread 0x7ffff7fc2740 (LWP 6032) "threads" (running)
2.1 Thread 0x7ffff7fc1700 (LWP 6037) "threads" (running)
2.2 Thread 0x7ffff77c0700 (LWP 6038) "threads" (running)
* 2.3 Thread 0x7ffff7fc2740 (LWP 6039) "threads" (running)
(gdb)
...
(gdb) thread 1.1
[Switching to thread 1.1 (Thread 0x7ffff7fc2740 (LWP 8155))]
(gdb)
...
etc.
You can still use "thread NUM", in which case GDB infers you're
referring to thread NUM of the current inferior.
The $_thread convenience var and Python's InferiorThread.num attribute
are remapped to the new per-inferior thread number. It's a backward
compatibility break, but since it only matters when debugging multiple
inferiors, I think it's worth doing.
Because MI thread IDs need to be a single integer, we keep giving
threads a global identifier, _in addition_ to the per-inferior number,
and make MI always refer to the global thread IDs. IOW, nothing
changes from a MI frontend's perspective.
Similarly, since Python's Breakpoint.thread and Guile's
breakpoint-thread/set-breakpoint-thread breakpoint methods need to
work with integers, those are adjusted to work with global thread IDs
too. Follow up patches will provide convenient means to access
threads' global IDs.
To avoid potencially confusing users (which also avoids updating much
of the testsuite), if there's only one inferior and its ID is "1",
IOW, the user hasn't done anything multi-process/inferior related,
then the "INF." part of thread IDs is not shown. E.g,.:
(gdb) info inferiors
Num Description Executable
* 1 process 15275 /home/pedro/gdb/tests/threads
(gdb) info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 15275) "threads" main () at threads.c:40
(gdb) add-inferior
Added inferior 2
(gdb) info threads
Id Target Id Frame
* 1.1 Thread 0x7ffff7fc1740 (LWP 15275) "threads" main () at threads.c:40
(gdb)
No regressions on x86_64 Fedora 20.
gdb/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
* NEWS: Mention that thread IDs are now per inferior and global
thread IDs.
* Makefile.in (SFILES): Add tid-parse.c.
(COMMON_OBS): Add tid-parse.o.
(HFILES_NO_SRCDIR): Add tid-parse.h.
* ada-tasks.c: Adjust to use ptid_to_global_thread_id.
* breakpoint.c (insert_breakpoint_locations)
(remove_threaded_breakpoints, bpstat_check_breakpoint_conditions)
(print_one_breakpoint_location, set_longjmp_breakpoint)
(check_longjmp_breakpoint_for_call_dummy)
(set_momentary_breakpoint): Adjust to use global IDs.
(find_condition_and_thread, watch_command_1): Use parse_thread_id.
(until_break_command, longjmp_bkpt_dtor)
(breakpoint_re_set_thread, insert_single_step_breakpoint): Adjust
to use global IDs.
* dummy-frame.c (pop_dummy_frame_bpt): Adjust to use
ptid_to_global_thread_id.
* elfread.c (elf_gnu_ifunc_resolver_stop): Likewise.
* gdbthread.h (struct thread_info): Rename field 'num' to
'global_num. Add new fields 'per_inf_num' and 'inf'.
(thread_id_to_pid): Rename thread_id_to_pid to
global_thread_id_to_ptid.
(pid_to_thread_id): Rename to ...
(ptid_to_global_thread_id): ... this.
(valid_thread_id): Rename to ...
(valid_global_thread_id): ... this.
(find_thread_id): Rename to ...
(find_thread_global_id): ... this.
(ALL_THREADS, ALL_THREADS_BY_INFERIOR): Declare.
(print_thread_info): Add comment.
* tid-parse.h: New file.
* tid-parse.c: New file.
* infcmd.c (step_command_fsm_prepare)
(step_command_fsm_should_stop): Adjust to use the global thread
ID.
(until_next_command, until_next_command)
(finish_command_fsm_should_stop): Adjust to use the global thread
ID.
(attach_post_wait): Adjust to check the inferior number too.
* inferior.h (struct inferior) <highest_thread_num>: New field.
* infrun.c (handle_signal_stop)
(insert_exception_resume_breakpoint)
(insert_exception_resume_from_probe): Adjust to use the global
thread ID.
* record-btrace.c (record_btrace_open): Use global thread IDs.
* remote.c (process_initial_stop_replies): Also consider the
inferior number.
* target.c (target_pre_inferior): Clear the inferior's highest
thread num.
* thread.c (clear_thread_inferior_resources): Adjust to use the
global thread ID.
(new_thread): New inferior parameter. Adjust to use it. Set both
the thread's global ID and the thread's per-inferior ID.
(add_thread_silent): Adjust.
(find_thread_global_id): New.
(find_thread_id): Make static. Adjust to rename.
(valid_thread_id): Rename to ...
(valid_global_thread_id): ... this.
(pid_to_thread_id): Rename to ...
(ptid_to_global_thread_id): ... this.
(thread_id_to_pid): Rename to ...
(global_thread_id_to_ptid): ... this. Adjust.
(first_thread_of_process): Adjust.
(do_captured_list_thread_ids): Adjust to use global thread IDs.
(should_print_thread): New function.
(print_thread_info): Rename to ...
(print_thread_info_1): ... this, and add new show_global_ids
parameter. Handle it. Iterate over inferiors.
(print_thread_info): Reimplement as wrapper around
print_thread_info_1.
(show_inferior_qualified_tids): New function.
(print_thread_id): Use it.
(tp_array_compar): Compare inferior numbers too.
(thread_apply_command): Use tid_range_parser.
(do_captured_thread_select): Use parse_thread_id.
(thread_id_make_value): Adjust.
(_initialize_thread): Adjust "info threads" help string.
* varobj.c (struct varobj_root): Update comment.
(varobj_create): Adjust to use global thread IDs.
(value_of_root_1): Adjust to use global_thread_id_to_ptid.
* windows-tdep.c (display_tib): No longer accept an argument.
* cli/cli-utils.c (get_number_trailer): Make extern.
* cli/cli-utils.h (get_number_trailer): Declare.
(get_number_const): Adjust documentation.
* mi/mi-cmd-var.c (mi_cmd_var_update_iter): Adjust to use global
thread IDs.
* mi/mi-interp.c (mi_new_thread, mi_thread_exit)
(mi_on_normal_stop, mi_output_running_pid, mi_on_resume):
* mi/mi-main.c (mi_execute_command, mi_cmd_execute): Likewise.
* guile/scm-breakpoint.c (gdbscm_set_breakpoint_thread_x):
Likewise.
* python/py-breakpoint.c (bppy_set_thread): Likewise.
* python/py-finishbreakpoint.c (bpfinishpy_init): Likewise.
* python/py-infthread.c (thpy_get_num): Add comment and return the
per-inferior thread ID.
(thread_object_getset): Update comment of "num".
gdb/testsuite/ChangeLog:
2016-01-07 Pedro Alves <palves@redhat.com>
* gdb.base/break.exp: Adjust to output changes.
* gdb.base/hbreak2.exp: Likewise.
* gdb.base/sepdebug.exp: Likewise.
* gdb.base/watch_thread_num.exp: Likewise.
* gdb.linespec/keywords.exp: Likewise.
* gdb.multi/info-threads.exp: Likewise.
* gdb.threads/thread-find.exp: Likewise.
* gdb.multi/tids.c: New file.
* gdb.multi/tids.exp: New file.
gdb/doc/ChangeLog:
2016-01-07 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Threads): Document per-inferior thread IDs,
qualified thread IDs, global thread IDs and thread ID lists.
(Set Watchpoints, Thread-Specific Breakpoints): Adjust to refer to
thread IDs.
(Convenience Vars): Document the $_thread convenience variable.
(Ada Tasks): Adjust to refer to thread IDs.
(GDB/MI Async Records, GDB/MI Thread Commands, GDB/MI Ada Tasking
Commands, GDB/MI Variable Objects): Update to mention global
thread IDs.
* guile.texi (Breakpoints In Guile)
<breakpoint-thread/set-breakpoint-thread breakpoint>: Mention
global thread IDs instead of thread IDs.
* python.texi (Threads In Python): Adjust documentation of
InferiorThread.num.
(Breakpoint.thread): Mention global thread IDs instead of thread
IDs.
[This reapplies a change that was accidentally reverted with c0ecb95f3d.]
Before:
(gdb) info threads
Id Target Id Frame
3 Thread 0x7ffff77c3700 (LWP 29035) callme () at foo.c:30
2 Thread 0x7ffff7fc4700 (LWP 29034) 0x000000000040087b in child_function_2 (arg=0x0) at foo.c:60
* 1 Thread 0x7ffff7fc5740 (LWP 29030) 0x0000003b37209237 in pthread_join (threadid=140737353893632, thread_return=0x0) at pthread_join.c:92
After:
(gdb) info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc5740 (LWP 29030) 0x0000003b37209237 in pthread_join (threadid=140737353893632, thread_return=0x0) at pthread_join.c:92
2 Thread 0x7ffff7fc4700 (LWP 29034) 0x000000000040087b in child_function_2 (arg=0x0) at foo.c:60
3 Thread 0x7ffff77c3700 (LWP 29035) callme () at foo.c:30
gdb/doc/ChangeLog:
2015-11-24 Pedro Alves <palves@redhat.com>
PR 17539
* gdb.texinfo (Inferiors and Programs): Adjust "maint info
program-spaces" example to ascending order listing.
(Threads): Adjust "info threads" example to ascending order
listing.
(Forks): Adjust "info inferiors" example to ascending order
listing.
gdb/ChangeLog:
2015-11-24 Pedro Alves <palves@redhat.com>
PR 17539
* inferior.c (add_inferior_silent): Append the new inferior to the
end of the list.
* progspace.c (add_program_space): Append the new pspace to the
end of the list.
* thread.c (new_thread): Append the new thread to the end of the
list.
gdb/testsuite/ChangeLog:
2015-11-24 Pedro Alves <palves@redhat.com>
PR 17539
* gdb.base/foll-exec-mode.exp: Adjust to GDB listing inferiors and
threads in ascending order.
* gdb.base/foll-fork.exp: Likewise.
* gdb.base/foll-vfork.exp: Likewise.
* gdb.base/multi-forks.exp: Likewise.
* gdb.mi/mi-nonstop.exp: Likewise.
* gdb.mi/mi-nsintrall.exp: Likewise.
* gdb.multi/base.exp: Likewise.
* gdb.multi/multi-arch.exp: Likewise.
* gdb.python/py-inferior.exp: Likewise.
* gdb.threads/break-while-running.exp: Likewise.
* gdb.threads/execl.exp: Likewise.
* gdb.threads/gcore-thread.exp: Likewise.
* gdb.threads/info-threads-cur-sal.exp: Likewise.
* gdb.threads/kill.exp: Likewise.
* gdb.threads/linux-dp.exp: Likewise.
* gdb.threads/multiple-step-overs.exp: Likewise.
* gdb.threads/next-bp-other-thread.exp: Likewise.
* gdb.threads/step-bg-decr-pc-switch-thread.exp: Likewise.
* gdb.threads/step-over-lands-on-breakpoint.exp: Likewise.
* gdb.threads/step-over-trips-on-watchpoint.exp: Likewise.
* gdb.threads/thread-find.exp: Likewise.
* gdb.threads/tls.exp: Likewise.
* lib/mi-support.exp (mi_reverse_list): Delete.
(mi_check_thread_states): No longer reverse list.
I was getting
gu (print arg0)^M
= 0x7fffffffdafb
"/unsafebuild-x86_64-redhat-linux-gnu/gdb/testsuite.unix.-m64/outputs/gdb.guile/scm-value/scm-"...^M
(gdb) FAIL: gdb.guile/scm-value.exp: verify dereferenced value
python print (arg0)^M
0x7fffffffdafd
"/unsafebuild-x86_64-redhat-linux-gnu/gdb/testsuite.unix.-m64/outputs/gdb.python/py-value/py-v"...^M
(gdb) FAIL: gdb.python/py-value.exp: verify dereferenced value
and also:
(gdb) p argv[0]^M
$2 = 0x7fffffffd832 "/home/jkratoch/redhat/gdb-test-", 'x' <repeats 169
times>...^M
(gdb) FAIL: gdb.guile/scm-value.exp: argv[0] should be available on this
target
gdb/testsuite/ChangeLog
2016-01-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.guile/scm-value.exp (test_value_in_inferior): Set print elements
and repeats to unlimited.
* gdb.python/py-value.exp: Likewise.
* lib/gdb.exp (gdb_has_argv0): Save and temporarily set print elements
and repeats to unlimited.
This patch removes all special cases for HP-UX, for which support has
been removed earlier, that I found in the testsuite. Note that the hppa
architecture != HP-UX, since other OSes can run on hppa, so I tried to
leave everything that is not HP-UX specific.
Two complete tests were completely HP-UX specific, so I removed them.
I ran the testsuite on Linux x86-64, native and native-gdbserver, and
noticed no regressions.
gdb/testsuite/ChangeLog:
* gdb.asm/asm-source.exp: Remove HP-UX references.
* gdb.base/annota1.exp: Likewise.
* gdb.base/annota3.exp: Likewise.
* gdb.base/attach.exp: Likewise.
* gdb.base/bigcore.exp: Likewise.
* gdb.base/break.exp: Likewise.
* gdb.base/call-ar-st.exp: Likewise.
* gdb.base/callfuncs.exp: Likewise.
* gdb.base/catch-fork-static.exp: Likewise.
* gdb.base/display.exp: Likewise.
* gdb.base/foll-exec-mode.exp: Likewise.
* gdb.base/foll-exec.exp: Likewise.
* gdb.base/foll-fork.exp: Likewise.
* gdb.base/foll-vfork.exp: Likewise.
* gdb.base/funcargs.exp: Likewise.
* gdb.base/hbreak2.exp: Likewise.
* gdb.base/inferior-died.exp: Likewise.
* gdb.base/interrupt.exp: Likewise.
* gdb.base/multi-forks.exp: Likewise.
* gdb.base/nodebug.exp: Likewise.
* gdb.base/sepdebug.exp: Likewise.
* gdb.base/solib1.c: Likewise.
* gdb.base/step-test.exp: Likewise.
* gdb.mi/non-stop.c: Likewise.
* gdb.mi/pthreads.c: Likewise.
* gdb.multi/bkpt-multi-exec.ex: Likewise.
* gdb.threads/pthreads.c: Likewise.
* gdb.threads/staticthreads.exp: Likewise.
* lib/future.exp: Likewise.
* lib/gdb.exp: Likewise.
* gdb.base/so-indr-cl.c: Remove.
* gdb.base/so-indr-cl.exp: Likewise.
* gdb.base/solib.c: Likewise.
* gdb.base/solib.exp: Likewise.
* gdb.base/solib2.c: Likewise.
This patch updates tests for fork and exec events in target remote mode.
In the majority of cases this was a simple matter of removing some code
that disabled the test for target remote. In a few cases the test needed
to be disabled; in those cases the gdb_protocol was checked instead of
using the [is_remote target] etc.
In a couple of cases we needed to use clean_restart, since target remote
doesn't support the run command, and in one case we had to modify an expect
expression to allow for a "multiprocess-style" ptid.
Tested with the patch that implemented target remote mode fork and exec
event support.
gdb/testsuite/ChangeLog:
* gdb.base/execl-update-breakpoints.exp (main): Enable for target
remote.
* gdb.base/foll-exec-mode.exp (main): Disable for target remote.
* gdb.base/foll-exec.exp (main): Enable for target remote.
* gdb.base/foll-fork.exp (main): Likewise.
* gdb.base/foll-vfork.exp (main): Likewise.
* gdb.base/multi-forks.exp (main): Likewise, and use clean_restart.
(proc continue_to_exit_bp_loc): Use clean_restart.
* gdb.base/pie-execl.exp (main): Disable for target remote.
* gdb.base/watch-vfork.exp (main): Enable for target remote.
* gdb.mi/mi-nsthrexec.exp (main): Likewise.
* gdb.threads/execl.exp (main): Likewise.
* gdb.threads/fork-child-threads.exp (main): Likewise.
* gdb.threads/fork-plus-threads.exp (main): Disable for target
remote.
* gdb.threads/fork-thread-pending.exp (main): Enable for target
remote.
* gdb.threads/linux-dp.exp (check_philosopher_stack): Allow
pid.tid style ptids, instead of just tid.
* gdb.threads/thread-execl.exp (main): Enable for target remote.
* gdb.threads/watchpoint-fork.exp (main): Likewise.
* gdb.trace/report.exp (use_collected_data): Allow pid.tid style
ptids, instead of just tid.
Testing with "maint set target-non-stop on" causes regressions in
tests that rely on TARGET_WAITKIND_NO_RESUMED, which isn't modelled on
the RSP. In real all-stop, gdbserver detects the situation and
reporst error to GDB, and so the tests (e.g.,
gdb.threads/no-unwaited-for-left.exp) at fail quickly. But with
"maint set target-non-stop on", GDB instead hangs forever waiting for
a stop reply that never comes, and so the tests take longer to time
out.
This adds a new "N" stop reply packet that maps 1-1 to
TARGET_WAITKIND_NO_RESUMED.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* NEWS (New remote packets): Mention the N stop reply.
* remote.c (remote_protocol_features): Add "no-resumed" entry.
(remote_query_supported): Report no-resumed+ support.
(remote_parse_stop_reply): Handle 'N'.
(process_stop_reply): Handle TARGET_WAITKIND_NO_RESUMED.
(remote_wait_as): Handle 'N' / TARGET_WAITKIND_NO_RESUMED.
(_initialize_remote): Register "set/show remote
no-resumed-stop-reply" commands.
gdb/doc/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* gdb.texinfo (Stop Reply Packets): Document the N stop reply.
(Remote Configuration): Add the "set/show remote
no-resumed-stop-reply" to the available settings table.
(General Query Packets): Document the "no-resumed" qSupported
feature.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* linux-low.c (linux_wait_1): If the last resumed thread is gone,
report TARGET_WAITKIND_NO_RESUMED.
* remote-utils.c (prepare_resume_reply): Handle
TARGET_WAITKIND_NO_RESUMED.
* server.c (report_no_resumed): New global.
(handle_query) <qSupported>: Handle "no-resumed+". Report
"no-resumed+" support.
(resume): When the target reports TARGET_WAITKIND_NO_RESUMED, only
return error if the client doesn't support no-resumed events.
(push_stop_notification): New function.
(handle_target_event): Use it. Report TARGET_WAITKIND_NO_RESUMED
events if the client supports them.
gdb/testsuite/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* gdb.threads/no-unwaited-for-left.exp: Remove setup_kfail calls.
I couldn't find a test that verified the thread name functionality, so I
created a new one.
A target board can define gdb,no_thread_names if it doesn't support thread
names and wants to skip the tests that uses them.
This test has been made with Linux in mind. Not all platforms use
pthread_setname_np to set the thread name, but some #ifdefs can be added
later in order to support other platforms.
Tested on x86-64 Ubuntu 14.04, native and remote.
gdb/testsuite/ChangeLog:
* gdb.threads/names.exp: New file.
* gdb.threads/names.c: New file.
* README: Mention gdb,no_thread_names.
Before:
(gdb) info threads
Id Target Id Frame
3 Thread 0x7ffff77c3700 (LWP 29035) callme () at foo.c:30
2 Thread 0x7ffff7fc4700 (LWP 29034) 0x000000000040087b in child_function_2 (arg=0x0) at foo.c:60
* 1 Thread 0x7ffff7fc5740 (LWP 29030) 0x0000003b37209237 in pthread_join (threadid=140737353893632, thread_return=0x0) at pthread_join.c:92
After:
(gdb) info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc5740 (LWP 29030) 0x0000003b37209237 in pthread_join (threadid=140737353893632, thread_return=0x0) at pthread_join.c:92
2 Thread 0x7ffff7fc4700 (LWP 29034) 0x000000000040087b in child_function_2 (arg=0x0) at foo.c:60
3 Thread 0x7ffff77c3700 (LWP 29035) callme () at foo.c:30
gdb/doc/ChangeLog:
2015-11-24 Pedro Alves <palves@redhat.com>
PR 17539
* gdb.texinfo (Inferiors and Programs): Adjust "maint info
program-spaces" example to ascending order listing.
(Threads): Adjust "info threads" example to ascending order
listing.
(Forks): Adjust "info inferiors" example to ascending order
listing.
gdb/ChangeLog:
2015-11-24 Pedro Alves <palves@redhat.com>
PR 17539
* inferior.c (add_inferior_silent): Append the new inferior to the
end of the list.
* progspace.c (add_program_space): Append the new pspace to the
end of the list.
* thread.c (new_thread): Append the new thread to the end of the
list.
gdb/testsuite/ChangeLog:
2015-11-24 Pedro Alves <palves@redhat.com>
PR 17539
* gdb.base/foll-exec-mode.exp: Adjust to GDB listing inferiors and
threads in ascending order.
* gdb.base/foll-fork.exp: Likewise.
* gdb.base/foll-vfork.exp: Likewise.
* gdb.base/multi-forks.exp: Likewise.
* gdb.mi/mi-nonstop.exp: Likewise.
* gdb.mi/mi-nsintrall.exp: Likewise.
* gdb.multi/base.exp: Likewise.
* gdb.multi/multi-arch.exp: Likewise.
* gdb.python/py-inferior.exp: Likewise.
* gdb.threads/break-while-running.exp: Likewise.
* gdb.threads/execl.exp: Likewise.
* gdb.threads/gcore-thread.exp: Likewise.
* gdb.threads/info-threads-cur-sal.exp: Likewise.
* gdb.threads/kill.exp: Likewise.
* gdb.threads/linux-dp.exp: Likewise.
* gdb.threads/multiple-step-overs.exp: Likewise.
* gdb.threads/next-bp-other-thread.exp: Likewise.
* gdb.threads/step-bg-decr-pc-switch-thread.exp: Likewise.
* gdb.threads/step-over-lands-on-breakpoint.exp: Likewise.
* gdb.threads/step-over-trips-on-watchpoint.exp: Likewise.
* gdb.threads/thread-find.exp: Likewise.
* gdb.threads/tls.exp: Likewise.
* lib/mi-support.exp (mi_reverse_list): Delete.
(mi_check_thread_states): No longer reverse list.
Nowadays, test gdb.threads/wp-replication.exp uses a while loop to
repeatedly insert HW watchpoint, resume and check no error message
coming out, in order to count HW watchpoints There are some
drawbacks in this way,
- the loop could be endless. I think this is use to making trouble
to S/390, since we had such comment
# Some targets (like S/390) behave as though supporting
# unlimited hardware watchpoints. In this case we just take a
# safe exit out of the loop.
I hit this today too because a GDB internal error is triggered
on "continue" in the loop, and $done is 0 invariantly, so the loop
can't end.
- the code counting hardware watchpoint is too complicated. We can
use "set breakpoint always-inserted on" to get the result of inserting
HW watchpoint without resuming the inferior. In this way,
watch_count_done and empty_cycle in c file is no longer needed.
In this patch, I change to use "set breakpoint always-inserted on" trick,
and only iterate $NR_THREADS times, to count the HW watchpoint. In this
way, the loop can't be endless, and GDB doesn't need to resume the inferior.
gdb/testsuite:
2015-10-30 Yao Qi <yao.qi@linaro.org>
* gdb.threads/wp-replication.c (watch_count_done): Remove.
(empty_cycle): Remove.
(main): Don't call empty_cycle. Don't use watch_count_done.
* gdb.threads/wp-replication.exp: Don't set breakpoint on
empty_cycle. Rewrite the code counting HW watchpoints.
On software single-step targets that don't support displaced stepping,
threads keep hitting each other's single-step breakpoints, and then
GDB needs to pause all threads to step past those. The end result is
that progress in the main thread will be slower and it may take a bit
longer for the signal to be queued. This patch bumps the timeout on
such targets.
gdb/testsuite/ChangeLog:
2015-09-16 Pedro Alves <palves@redhat.com>
Sandra Loosemore <sandra@codesourcery.com>
* gdb.threads/non-stop-fair-events.c (timeout): New global.
(SECONDS): Redefine.
(main): Call pthread_kill and alarm early.
* gdb.threads/non-stop-fair-events.exp: Probe displaced stepping
support.
(test): If the target can't hardware step and doesn't support
displaced stepping, increase the timeout.
If we enable infrun debug running this test, it quickly fails with a
full expect buffer. That can be simply handled with a couple
exp_continues. As it's annoying to hack this every time we need to
debug the test, this patch adds bits to enable debugging support
easily, with a one-line change.
And then, if any iteration of the test fails, we end up with a long
cascade of time outs. Just bail out when we see the first fail.
gdb/testsuite/
2015-09-16 Pedro Alves <palves@redhat.com>
* gdb.threads/non-stop-fair-events.exp (gdb_test_no_anchor)
(enable_debug): New procedures.
(test): Use them. Bail out if waiting for threads fails.
(top level): Bail out if a test fails.
gdb.threads/non-ldr-exc-3.exp is sometimes failing like this:
[Switching to Thread 6831.6832]
Breakpoint 2, thread_execler (arg=0x0) at /home/pedro/gdb/mygit/build/../src/gdb/testsuite/gdb.threads/non-ldr-exc-3.c:41
41 if (execl (image, image, argv1, NULL) == -1) /* break-here */
PASS: gdb.threads/non-ldr-exc-3.exp: lock-sched=on,non-stop=off: continue to breakpoint
(gdb) set scheduler-locking on
(gdb) FAIL: gdb.threads/non-ldr-exc-3.exp: lock-sched=on,non-stop=off: set scheduler-locking on
The problem is that the gdb_test_multiple is missing the prompt
anchor. The problem was introduced by 2fd33e9448. This reverts the
hunk that introduced the problem, reverting back to
gdb_continue_to_breakpoint.
gdb/testsuite/ChangeLog:
2015-09-15 Pedro Alves <palves@redhat.com>
* gdb.threads/non-ldr-exc-3.exp (do_test): Use
gdb_continue_to_breakpoint instead of gdb_test_multiple.
This patch updates several exec-related tests and some of the library
functions in order to get them running with extended-remote. There were
three changes that were required, as follows:
In gdb.base/foll-exec.exp, use 'clean_start' in place of proc 'zap_session'
to reset the state of the debugger between tests. This sets 'remote
exec-file' to execute the correct binary file in each subsequent test.
In gdb.base/pie-execl.exp, there is an expect statement with an expression
that is used to match output from both gdb and the program under debug.
For the remote target, this had to be split into two expressions, using
$inferior_spawn_id to match the output from the program.
Because I had encountered problems with extended-remote exec events in
non-stop mode in my manual testing, I added non-stop testing to the
non-ldr-exc-[1234].exp tests. In order to set non-stop mode for remote
targets, it is necessary to 'set non-stop on' after gdb has started, but
before it connects to gdbserver. This is done using 'save_vars' to set
non-stop mode in GDBFLAGS, so GDB sets non-stop mode on startup.
gdb/testsuite/ChangeLog:
* gdb.base/foll-exec.c: Add copyright header. Fix
formatting issues.
* gdb.base/foll-exec.exp (zap_session): Delete proc.
(do_exec_tests): Use clean_restart in place of zap_session,
and for test initialization. Fix formatting issues. Use
fail in place of perror.
* gdb.base/pie-execl.exp (main): Use 'inferior_spawn_id' in
an expect statement to match an expression with output from
the program under debug.
* gdb.threads/non-ldr-exc-1.exp (do_test, main): Add
non-stop tests and pass stop mode argument to clean_restart.
Use save_vars to enable non-stop in GDBFLAGS.
* gdb.threads/non-ldr-exc-2.exp: Likewise.
* gdb.threads/non-ldr-exc-3.exp: Likewise.
* gdb.threads/non-ldr-exc-4.exp: Likewise.
2015-09-08 Sandra Loosemore <sandra@codesourcery.com>
gdb/testsuite/
* gdb.threads/hand-call-in-threads.exp: Make sure the thread
command actually switches threads. Give up on remaining
tests if target fails to stop at breakpoint.
On a target that is both always in non-stop mode and can do displaced
stepping (such as native x86_64 GNU/Linux, with "maint set
target-non-stop on"), the step-over-trips-on-watchpoint.exp test
sometimes fails like this:
(gdb) PASS: gdb.threads/step-over-trips-on-watchpoint.exp: no thread-specific bp: step: thread 1
set scheduler-locking off
(gdb) PASS: gdb.threads/step-over-trips-on-watchpoint.exp: no thread-specific bp: step: set scheduler-locking off
step
-[Switching to Thread 0x7ffff7fc0700 (LWP 11782)]
-Hardware watchpoint 4: watch_me
-
-Old value = 0
-New value = 1
-child_function (arg=0x0) at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.threads/step-over-trips-on-watchpoint.c:39
-39 other = 1; /* set thread-specific breakpoint here */
-(gdb) PASS: gdb.threads/step-over-trips-on-watchpoint.exp: no thread-specific bp: step: step
+wait_threads () at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.threads/step-over-trips-on-watchpoint.c:49
+49 return 1; /* in wait_threads */
+(gdb) FAIL: gdb.threads/step-over-trips-on-watchpoint.exp: no thread-specific bp: step: step
Note "scheduler-locking" was set off. The problem is that on such
targets, the step-over of thread 2 and the "step" of thread 1 can be
set to run simultaneously (since with displaced stepping the
breakpoint isn't ever removed from the target), and sometimes, the
"step" of thread 1 finishes first, so it'd take another resume to see
the watchpoint trigger. Fix this by replacing the wait_threads
function with a one-line infinite loop that doesn't call any function,
so that the "step" of thread 1 never finishes.
gdb/testsuite/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* gdb.threads/step-over-lands-on-breakpoint.c (wait_threads):
Delete function.
(main): Add alarm. Run an infinite loop instead of calling
wait_threads.
* gdb.threads/step-over-lands-on-breakpoint.exp (do_test): Change
comment.
* gdb.threads/step-over-trips-on-watchpoint.c (wait_threads):
Delete function.
(main): Add alarm. Run an infinite loop instead of calling
wait_threads.
* gdb.threads/step-over-trips-on-watchpoint.exp (do_test): Change
comment.
With "maint set target-non-stop on" we get:
-PASS: gdb.threads/signal-while-stepping-over-bp-other-thread.exp: step
+FAIL: gdb.threads/signal-while-stepping-over-bp-other-thread.exp: step
The issue is simply that switch_back_to_stepped_thread is not used in
non-stop mode, thus infrun doesn't output the expected "switching back
to stepped thread" log.
gdb/testsuite/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* signal-while-stepping-over-bp-other-thread.exp: Expect "restart
threads" as alternative to "switching back to stepped thread".
This adds a kfailed test that has the whole process exit just while
several threads continuously step over a breakpoint. Usually, the
process exits just while GDB or GDBserver is handling the breakpoint
hit. In other words, the process disappears while the event thread is
(ptrace-) stopped. This exposes several issues in GDB and GDBserver.
Errors, crashes, etc.
I fixed some of these issues recently, but there's a lot more to do.
It's a bit like playing whack-a-mole at the moment. You fix an issue,
which then exposes several others.
E.g., with the native target, you get (among other errors):
(...)
[New Thread 0x7ffff47b9700 (LWP 18077)]
[New Thread 0x7ffff3fb8700 (LWP 18078)]
[New Thread 0x7ffff37b7700 (LWP 18079)]
Cannot find user-level thread for LWP 18076: generic error
(gdb) KFAIL: gdb.threads/process-dies-while-handling-bp.exp: non_stop=on: cond_bp_target=1: inferior 1 exited (prompt) (PRMS: gdb/18749)
gdb/testsuite/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
PR gdb/18749
* gdb.threads/process-dies-while-handling-bp.c: New file.
* gdb.threads/process-dies-while-handling-bp.exp: New file.
Ref: https://sourceware.org/ml/gdb-patches/2015-07/msg00868.html
This adds a test that has a multithreaded program have several threads
continuously fork, while another thread continuously steps over a
breakpoint.
This exposes several intertwined issues, which this patch addresses:
- When we're stopping and suspending threads, some thread may fork,
and we missed setting its suspend count to 1, like we do when a new
clone/thread is detected. When we next unsuspend threads, the fork
child's suspend count goes below 0, which is bogus and fails an
assertion.
- If a step-over is cancelled because a signal arrives, but then gdb
is not interested in the signal, we pass the signal straight back
to the inferior. However, we miss that we need to re-increment the
suspend counts of all other threads that had been paused for the
step-over. As a result, other threads indefinitely end up stuck
stopped.
- If a detach request comes in just while gdbserver is handling a
step-over (in the test at hand, this is GDB detaching the fork
child), gdbserver internal errors in stabilize_thread's helpers,
which assert that all thread's suspend counts are 0 (otherwise we
wouldn't be able to move threads out of the jump pads). The
suspend counts aren't 0 while a step-over is in progress, because
all threads but the one stepping past the breakpoint must remain
paused until the step-over finishes and the breakpoint can be
reinserted.
- Occasionally, we see "BAD - reinserting but not stepping." being
output (from within linux_resume_one_lwp_throw). That was because
GDB pokes memory while gdbserver is busy with a step-over, and that
suspends threads, and then re-resumes them with proceed_one_lwp,
which missed another reason to tell linux_resume_one_lwp that the
thread should be set back to stepping.
- In a couple places, we were resuming threads that are meant to be
suspended. E.g., when a vCont;c/s request for thread B comes in
just while gdbserver is stepping thread A past a breakpoint. The
resume for thread B must be deferred until the step-over finishes.
- The test runs with both "set detach-on-fork" on and off. When off,
it exercises the case of GDB detaching the fork child explicitly.
When on, it exercises the case of gdb resuming the child
explicitly. In the "off" case, gdb seems to exponentially become
slower as new inferiors are created. This is _very_ noticeable as
with only 100 inferiors gdb is crawling already, which makes the
test take quite a bit to run. For that reason, I've disabled the
"off" variant for now.
gdb/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* target/waitstatus.h (enum target_stop_reason)
<TARGET_STOPPED_BY_SINGLE_STEP>: New value.
gdb/gdbserver/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Set the fork child's suspend
count if stopping and suspending threads.
(check_stopped_by_breakpoint): If stopped by trace, set the LWP's
stop reason to TARGET_STOPPED_BY_SINGLE_STEP.
(linux_detach): Complete an ongoing step-over.
(lwp_suspended_inc, lwp_suspended_decr): New functions. Use
throughout.
(resume_stopped_resumed_lwps): Don't resume a suspended thread.
(linux_wait_1): If passing a signal to the inferior after
finishing a step-over, unsuspend and re-resume all lwps. If we
see a single-step event but the thread should be continuing, don't
pass the trap to gdb.
(stuck_in_jump_pad_callback, move_out_of_jump_pad_callback): Use
internal_error instead of gdb_assert.
(enqueue_pending_signal): New function.
(check_ptrace_stopped_lwp_gone): Add debug output.
(start_step_over): Use internal_error instead of gdb_assert.
(complete_ongoing_step_over): New function.
(linux_resume_one_thread): Don't resume a suspended thread.
(proceed_one_lwp): If the LWP is stepping over a breakpoint, reset
it stepping.
gdb/testsuite/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* gdb.threads/forking-threads-plus-breakpoint.exp: New file.
* gdb.threads/forking-threads-plus-breakpoint.c: New file.
At https://sourceware.org/ml/gdb-patches/2015-08/msg00097.html, Joel
observed that trying to next/step a program on GNU/Linux sometimes
results in the following failed assertion:
% gdb -q .obj/gprof/main
(gdb) start
(gdb) n
(gdb) step
[...]/infrun.c:2391: internal-error:
resume: Assertion `sig != GDB_SIGNAL_0' failed.
What happened is that, during the "next" operation, GDB hit a
longjmp/exception/step-resume breakpoint but failed to see that this
breakpoint was set for a different thread than the one being stepped.
Joel's detailed analysis follows:
More precisely, at the end of the "start" command, we are stopped at
the start of function Main in main.adb; there are 4 threads in total,
and we are in the main thread (which is thread 1):
(gdb) info thread
Id Target Id Frame
4 Thread 0xb7a56ba0 (LWP 28379) 0xffffe410 in __kernel_vsyscall ()
3 Thread 0xb7c5aba0 (LWP 28378) 0xffffe410 in __kernel_vsyscall ()
2 Thread 0xb7e5eba0 (LWP 28377) 0xffffe410 in __kernel_vsyscall ()
* 1 Thread 0xb7ea18c0 (LWP 28370) main () at /[...]/main.adb:57
All the logs below reference Thread ID/LWP, but it'll be easier to
talk about the threads by GDB thread number. For instance, thread 1
is LWP 28370 while thread 3 is LWP 28378. So, the explanations below
translate the LWPs into thread numbers.
Back to what happens while we are trying to "next' our program:
(gdb) n
infrun: clear_proceed_status_thread (Thread 0xb7a56ba0 (LWP 28379))
infrun: clear_proceed_status_thread (Thread 0xb7c5aba0 (LWP 28378))
infrun: clear_proceed_status_thread (Thread 0xb7e5eba0 (LWP 28377))
infrun: clear_proceed_status_thread (Thread 0xb7ea18c0 (LWP 28370))
infrun: proceed (addr=0xffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0xb7ea18c0 (LWP 28370)] at 0x805451e
infrun: target_wait (-1.0.0, status) =
infrun: 28370.28370.0 [Thread 0xb7ea18c0 (LWP 28370)],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x8054523
We've resumed thread 1 (LWP 28370), and received in return a signal
that the same thread stopped slightly further. It's still in the
range of instructions for the line of source we started the "next"
from, as evidenced by the following trace...
infrun: stepping inside range [0x805451e-0x8054531]
... and thus, we decide to continue stepping the same thread:
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0xb7ea18c0 (LWP 28370)] at 0x8054523
infrun: prepare_to_wait
That's when we get an event from a different thread (thread 3)...
infrun: target_wait (-1.0.0, status) =
infrun: 28370.28378.0 [Thread 0xb7c5aba0 (LWP 28378)],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x80782d0
infrun: context switch
infrun: Switching context from Thread 0xb7ea18c0 (LWP 28370) to Thread 0xb7c5aba0 (LWP 28378)
... which we find to be at the address where we set a breakpoint on
"the unwinder debug hook" (namely "_Unwind_DebugHook"). But GDB fails
to notice that the breakpoint was inserted for thread 1 only, and so
decides to handle it as...
infrun: BPSTAT_WHAT_SET_LONGJMP_RESUME
... and inserts a breakpoint at the corresponding resume address, as
evidenced by this the next log:
infrun: exception resume at 80542a2
That breakpoint seems innocent right now, but will play a role fairly
quickly. But for now, GDB has inserted the exception-resume
breakpoint, and needs to single-step thread 3 past the breakpoint it
just hit. Thus, it temporarily disables the exception breakpoint, and
requests a step of that thread:
infrun: skipping breakpoint: stepping past insn at: 0x80782d0
infrun: skipping breakpoint: stepping past insn at: 0x80782d0
infrun: skipping breakpoint: stepping past insn at: 0x80782d0
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 0xb7c5aba0 (LWP 28378)] at 0x80782d0
infrun: prepare_to_wait
We then get a notification, still from thread 3, that it's now past
that breakpoint...
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 28370.28378.0 [Thread 0xb7c5aba0 (LWP 28378)],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x8078424
... so we can resume what we were doing before, which is single-stepping
thread 1 until we get to a new line of code:
infrun: switching back to stepped thread
infrun: Switching context from Thread 0xb7c5aba0 (LWP 28378) to Thread 0xb7ea18c0 (LWP 28370)
infrun: expected thread still hasn't advanced
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0xb7ea18c0 (LWP 28370)] at 0x8054523
The "resume" log above shows that we're resuming thread 1 from where
we left off (0x8054523). We get one more stop at 0x8054529, which is
still inside our stepping range so we go again. That's when we get
the following event, from thread 3:
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 28370.28378.0 [Thread 0xb7c5aba0 (LWP 28378)],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x80542a2
Now the stop_pc address is interesting, because it's the address of
"exception resume" breakpoint...
infrun: context switch
infrun: Switching context from Thread 0xb7ea18c0 (LWP 28370) to Thread 0xb7c5aba0 (LWP 28378)
infrun: BPSTAT_WHAT_CLEAR_LONGJMP_RESUME
... and since that location is at a different line of code, this is
where it decides the "next" operation should stop:
infrun: stop_waiting
[Switching to Thread 0xb7c5aba0 (LWP 28378)]
0x080542a2 in inte_tache_rt.ttache_rt (
<_task>=0x80968ec <inte_tache_rt_inst.tache2>)
at /[...]/inte_tache_rt.adb:54
54 end loop;
However, what GDB should have noticed earlier that the exception
breakpoint we hit was for a different thread, thus should have
single-stepped that thread out of the breakpoint _without_ inserting
the exception-return breakpoint, and then resumed the single-stepping
of the initial thread (thread 1) until that thread stepped out of its
stepping range.
This is what this patch does, and after applying it, GDB now correctly
stops on the next line of code.
The patch adds a C++ test that exercises this, both for setjmp/longjmp
and exception breakpoints. With an unpatched GDB it shows:
(gdb) next
[Switching to Thread 22445.22455]
thread_try_catch (arg=0x0) at /home/pedro/gdb/mygit/build/../src/gdb/testsuite/gdb.threads/next-other-thr-longjmp.c:59
59 catch (...)
(gdb) FAIL: gdb.threads/next-other-thr-longjmp.exp: next to line 1
next
/home/pedro/gdb/mygit/build/../src/gdb/infrun.c:4865: internal-error: process_event_stop_test: Assertion `ecs->event_thread->control.exception_resume_breakpoint != NULL' fa
iled.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.threads/next-other-thr-longjmp.exp: next to line 2 (GDB internal error)
Resyncing due to internal error.
n
Tested on x86_64-linux, no regressions.
gdb/ChangeLog:
2015-08-05 Pedro Alves <palves@redhat.com>
Joel Brobecker <brobecker@adacore.com>
* breakpoint.c (bpstat_what) <bp_longjmp, bp_longjmp_call_dummy>
<bp_exception, bp_longjmp_resume, bp_exception_resume>: Handle the
case where BS->STOP is not set.
gdb/testsuite/ChangeLog:
2015-08-05 Pedro Alves <palves@redhat.com>
* gdb.threads/next-while-other-thread-longjmps.c: New file.
* gdb.threads/next-while-other-thread-longjmps.exp: New file.
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.
Running gdb.threads/fork-plus-threads.exp against gdbserver in
extended-remote mode, even though the test passes, we still see broken
behavior:
(gdb) PASS: gdb.threads/fork-plus-threads.exp: set detach-on-fork off
continue &
Continuing.
(gdb) PASS: gdb.threads/fork-plus-threads.exp: continue &
[New Thread 28092.28092]
[Thread 28092.28092] #2 stopped.
[New Thread 28094.28094]
[Inferior 2 (process 28092) exited normally]
[New Thread 28094.28105]
[New Thread 28094.28109]
...
[Thread 28174.28174] #18 stopped.
[New Thread 28185.28185]
[Inferior 10 (process 28174) exited normally]
[New Thread 28185.28196]
[Thread 28185.28185] #20 stopped.
Cannot remove breakpoints because program is no longer writable.
Further execution is probably impossible.
[Inferior 11 (process 28185) exited normally]
[Inferior 1 (process 28091) exited normally]
PASS: gdb.threads/fork-plus-threads.exp: reached breakpoint
info threads
No threads.
(gdb) PASS: gdb.threads/fork-plus-threads.exp: no threads left
info inferiors
Num Description Executable
* 1 <null> /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.threads/fork-plus-threads
(gdb) PASS: gdb.threads/fork-plus-threads.exp: only inferior 1 left
All the "[Thread FOO] #NN stopped." above are bogus, as well as the
"Cannot remove breakpoints because program is no longer writable.",
which is a consequence.
The problem is that when we intercept a fork event, we should report
the event for the parent, only, and leave the child stopped, but not
report its stop event. GDB later decides whether to follow the parent
or the child. But because handle_extended_wait does not set the
child's last_status.kind to TARGET_WAITKIND_STOPPED, a
stop_all_threads/unstop_all_lwps sequence (e.g., from trying to access
memory) by mistake ends up queueing a SIGSTOP on the child, resuming
it, and then when that SIGSTOP is intercepted, because the LWP has
last_resume_kind set to resume_stop, gdbserver reports the stop to
GDB, as GDB_SIGNAL_0:
...
>>>> entering unstop_all_lwps
unstopping all lwps
proceed_one_lwp: lwp 1600
client wants LWP to remain 1600 stopped
proceed_one_lwp: lwp 1828
Client wants LWP 1828 to stop. Making sure it has a SIGSTOP pending
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Sending sigstop to lwp 1828
pc is 0x3615ebc7cc
Resuming lwp 1828 (continue, signal 0, stop expected)
continue from pc 0x3615ebc7cc
unstop_all_lwps done
sigchld_handler
<<<< exiting unstop_all_lwps
handling possible target event
>>>> entering linux_wait_1
linux_wait_1: [<all threads>]
my_waitpid (-1, 0x40000001)
my_waitpid (-1, 0x1): status(137f), 1828
LWFE: waitpid(-1, ...) returned 1828, ERRNO-OK
LLW: waitpid 1828 received Stopped (signal) (stopped)
pc is 0x3615ebc7cc
Expected stop.
LLW: resume_stop SIGSTOP caught for LWP 1828.1828.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
linux_wait_1 ret = LWP 1828.1828, 1, 0
<<<< exiting linux_wait_1
Writing resume reply for LWP 1828.1828:1
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Tested on x86_64 Fedora 20, extended-remote.
gdb/gdbserver/ChangeLog:
2015-07-30 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Set the child's last
reported status to TARGET_WAITKIND_STOPPED.
Joel Brobecker
Luis Machado
Yao Qi
Tom Tromey
Pedro Alves
Andrew Burgess
Simon Marchi
Don Breazeal
Jan Kratochvil
Simon Marchi
Sandra Loosemore
Philippe Waroquiers