| Message ID | 20210930095111.23205-1-pavel@labath.sk |
|---|---|
| State | New |
| Headers | show |
| Series | gdbstub: Switch to the thread receiving a signal | expand |
Ping. (This is my first qemu patch, so please let me know if I am doing something wrong.) regards, pavel On 30/09/2021 11:51, Pavel Labath wrote: > Respond with Txxthread:yyyy; instead of a plain Sxx to indicate which > thread received the signal. Otherwise, the debugger will associate it > with the main one. Also automatically select this thread, as that is > what gdb expects. > > Signed-off-by: Pavel Labath <pavel@labath.sk> > --- > gdbstub.c | 9 ++- > tests/tcg/multiarch/Makefile.target | 7 +++ > .../gdbstub/test-thread-breakpoint.py | 60 +++++++++++++++++++ > 3 files changed, 74 insertions(+), 2 deletions(-) > create mode 100644 tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py > > diff --git a/gdbstub.c b/gdbstub.c > index 36b85aa..7bd4479 100644 > --- a/gdbstub.c > +++ b/gdbstub.c > @@ -3138,8 +3138,13 @@ gdb_handlesig(CPUState *cpu, int sig) > tb_flush(cpu); > > if (sig != 0) { > - snprintf(buf, sizeof(buf), "S%02x", target_signal_to_gdb(sig)); > - put_packet(buf); > + gdbserver_state.c_cpu = cpu; > + gdbserver_state.g_cpu = cpu; > + g_string_printf(gdbserver_state.str_buf, > + "T%02xthread:", target_signal_to_gdb(sig)); > + gdb_append_thread_id(cpu, gdbserver_state.str_buf); > + g_string_append_c(gdbserver_state.str_buf, ';'); > + put_strbuf(); > } > /* put_packet() might have detected that the peer terminated the > connection. */ > diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target > index 85a6fb7..c7b7e8b 100644 > --- a/tests/tcg/multiarch/Makefile.target > +++ b/tests/tcg/multiarch/Makefile.target > @@ -73,6 +73,13 @@ run-gdbstub-qxfer-auxv-read: sha1 > --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \ > "basic gdbstub qXfer:auxv:read support") > > +run-gdbstub-thread-breakpoint: testthread > + $(call run-test, $@, $(GDB_SCRIPT) \ > + --gdb $(HAVE_GDB_BIN) \ > + --qemu $(QEMU) --qargs "$(QEMU_OPTS)" \ > + --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-thread-breakpoint.py, \ > + "hitting a breakpoint on non-main thread") > + > else > run-gdbstub-%: > $(call skip-test, "gdbstub test $*", "need working gdb") > diff --git a/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py > new file mode 100644 > index 0000000..798d508 > --- /dev/null > +++ b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py > @@ -0,0 +1,60 @@ > +from __future__ import print_function > +# > +# Test auxiliary vector is loaded via gdbstub > +# > +# This is launched via tests/guest-debug/run-test.py > +# > + > +import gdb > +import sys > + > +failcount = 0 > + > +def report(cond, msg): > + "Report success/fail of test" > + if cond: > + print ("PASS: %s" % (msg)) > + else: > + print ("FAIL: %s" % (msg)) > + global failcount > + failcount += 1 > + > +def run_test(): > + "Run through the tests one by one" > + > + sym, ok = gdb.lookup_symbol("thread1_func") > + gdb.execute("b thread1_func") > + gdb.execute("c") > + > + frame = gdb.selected_frame() > + report(str(frame.function()) == "thread1_func", "break @ %s"%frame) > + > +# > +# This runs as the script it sourced (via -x, via run-test.py) > +# > +try: > + inferior = gdb.selected_inferior() > + arch = inferior.architecture() > + print("ATTACHED: %s" % arch.name()) > +except (gdb.error, AttributeError): > + print("SKIPPING (not connected)", file=sys.stderr) > + exit(0) > + > +if gdb.parse_and_eval('$pc') == 0: > + print("SKIP: PC not set") > + exit(0) > + > +try: > + # These are not very useful in scripts > + gdb.execute("set pagination off") > + gdb.execute("set confirm off") > + > + # Run the actual tests > + run_test() > +except (gdb.error): > + print ("GDB Exception: %s" % (sys.exc_info()[0])) > + failcount += 1 > + pass > + > +print("All tests complete: %d failures" % failcount) > +exit(failcount) >
Pavel Labath <pavel@labath.sk> writes: > Ping. > > (This is my first qemu patch, so please let me know if I am doing > something wrong.) Apologies it slipped though the cracks. I shall have a look on Monday. > > regards, > pavel > > On 30/09/2021 11:51, Pavel Labath wrote: >> Respond with Txxthread:yyyy; instead of a plain Sxx to indicate which >> thread received the signal. Otherwise, the debugger will associate it >> with the main one. Also automatically select this thread, as that is >> what gdb expects. >> Signed-off-by: Pavel Labath <pavel@labath.sk> >> --- >> gdbstub.c | 9 ++- >> tests/tcg/multiarch/Makefile.target | 7 +++ >> .../gdbstub/test-thread-breakpoint.py | 60 +++++++++++++++++++ >> 3 files changed, 74 insertions(+), 2 deletions(-) >> create mode 100644 tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py >> diff --git a/gdbstub.c b/gdbstub.c >> index 36b85aa..7bd4479 100644 >> --- a/gdbstub.c >> +++ b/gdbstub.c >> @@ -3138,8 +3138,13 @@ gdb_handlesig(CPUState *cpu, int sig) >> tb_flush(cpu); >> if (sig != 0) { >> - snprintf(buf, sizeof(buf), "S%02x", target_signal_to_gdb(sig)); >> - put_packet(buf); >> + gdbserver_state.c_cpu = cpu; >> + gdbserver_state.g_cpu = cpu; >> + g_string_printf(gdbserver_state.str_buf, >> + "T%02xthread:", target_signal_to_gdb(sig)); >> + gdb_append_thread_id(cpu, gdbserver_state.str_buf); >> + g_string_append_c(gdbserver_state.str_buf, ';'); >> + put_strbuf(); >> } >> /* put_packet() might have detected that the peer terminated the >> connection. */ >> diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target >> index 85a6fb7..c7b7e8b 100644 >> --- a/tests/tcg/multiarch/Makefile.target >> +++ b/tests/tcg/multiarch/Makefile.target >> @@ -73,6 +73,13 @@ run-gdbstub-qxfer-auxv-read: sha1 >> --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \ >> "basic gdbstub qXfer:auxv:read support") >> +run-gdbstub-thread-breakpoint: testthread >> + $(call run-test, $@, $(GDB_SCRIPT) \ >> + --gdb $(HAVE_GDB_BIN) \ >> + --qemu $(QEMU) --qargs "$(QEMU_OPTS)" \ >> + --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-thread-breakpoint.py, \ >> + "hitting a breakpoint on non-main thread") >> + >> else >> run-gdbstub-%: >> $(call skip-test, "gdbstub test $*", "need working gdb") >> diff --git a/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py >> new file mode 100644 >> index 0000000..798d508 >> --- /dev/null >> +++ b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py >> @@ -0,0 +1,60 @@ >> +from __future__ import print_function >> +# >> +# Test auxiliary vector is loaded via gdbstub >> +# >> +# This is launched via tests/guest-debug/run-test.py >> +# >> + >> +import gdb >> +import sys >> + >> +failcount = 0 >> + >> +def report(cond, msg): >> + "Report success/fail of test" >> + if cond: >> + print ("PASS: %s" % (msg)) >> + else: >> + print ("FAIL: %s" % (msg)) >> + global failcount >> + failcount += 1 >> + >> +def run_test(): >> + "Run through the tests one by one" >> + >> + sym, ok = gdb.lookup_symbol("thread1_func") >> + gdb.execute("b thread1_func") >> + gdb.execute("c") >> + >> + frame = gdb.selected_frame() >> + report(str(frame.function()) == "thread1_func", "break @ %s"%frame) >> + >> +# >> +# This runs as the script it sourced (via -x, via run-test.py) >> +# >> +try: >> + inferior = gdb.selected_inferior() >> + arch = inferior.architecture() >> + print("ATTACHED: %s" % arch.name()) >> +except (gdb.error, AttributeError): >> + print("SKIPPING (not connected)", file=sys.stderr) >> + exit(0) >> + >> +if gdb.parse_and_eval('$pc') == 0: >> + print("SKIP: PC not set") >> + exit(0) >> + >> +try: >> + # These are not very useful in scripts >> + gdb.execute("set pagination off") >> + gdb.execute("set confirm off") >> + >> + # Run the actual tests >> + run_test() >> +except (gdb.error): >> + print ("GDB Exception: %s" % (sys.exc_info()[0])) >> + failcount += 1 >> + pass >> + >> +print("All tests complete: %d failures" % failcount) >> +exit(failcount) >>
On 15/10/2021 17:59, Alex Bennée wrote: > > Pavel Labath <pavel@labath.sk> writes: > >> Ping. >> >> (This is my first qemu patch, so please let me know if I am doing >> something wrong.) > > Apologies it slipped though the cracks. I shall have a look on Monday. > I don't want to impose, but did this get buried over the weekend by any chance? regards, pl
Pavel Labath <pavel@labath.sk> writes: > Respond with Txxthread:yyyy; instead of a plain Sxx to indicate which > thread received the signal. Otherwise, the debugger will associate it > with the main one. Also automatically select this thread, as that is > what gdb expects. > > Signed-off-by: Pavel Labath <pavel@labath.sk> > --- > gdbstub.c | 9 ++- > tests/tcg/multiarch/Makefile.target | 7 +++ > .../gdbstub/test-thread-breakpoint.py | 60 +++++++++++++++++++ > 3 files changed, 74 insertions(+), 2 deletions(-) > create mode 100644 tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py > > diff --git a/gdbstub.c b/gdbstub.c > index 36b85aa..7bd4479 100644 > --- a/gdbstub.c > +++ b/gdbstub.c > @@ -3138,8 +3138,13 @@ gdb_handlesig(CPUState *cpu, int sig) > tb_flush(cpu); > > if (sig != 0) { > - snprintf(buf, sizeof(buf), "S%02x", target_signal_to_gdb(sig)); > - put_packet(buf); > + gdbserver_state.c_cpu = cpu; > + gdbserver_state.g_cpu = cpu; > + g_string_printf(gdbserver_state.str_buf, > + "T%02xthread:", target_signal_to_gdb(sig)); > + gdb_append_thread_id(cpu, gdbserver_state.str_buf); > + g_string_append_c(gdbserver_state.str_buf, ';'); > + put_strbuf(); > } > /* put_packet() might have detected that the peer terminated the > connection. */ > diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target > index 85a6fb7..c7b7e8b 100644 > --- a/tests/tcg/multiarch/Makefile.target > +++ b/tests/tcg/multiarch/Makefile.target > @@ -73,6 +73,13 @@ run-gdbstub-qxfer-auxv-read: sha1 > --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \ > "basic gdbstub qXfer:auxv:read support") > > +run-gdbstub-thread-breakpoint: testthread > + $(call run-test, $@, $(GDB_SCRIPT) \ > + --gdb $(HAVE_GDB_BIN) \ > + --qemu $(QEMU) --qargs "$(QEMU_OPTS)" \ > + --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-thread-breakpoint.py, \ > + "hitting a breakpoint on non-main thread") > + You also need to add the test to EXTRA_RUNS here (or just bellow in fact). > else > run-gdbstub-%: > $(call skip-test, "gdbstub test $*", "need working gdb") > diff --git a/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py > new file mode 100644 > index 0000000..798d508 > --- /dev/null > +++ b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py > @@ -0,0 +1,60 @@ > +from __future__ import print_function > +# > +# Test auxiliary vector is loaded via gdbstub > +# > +# This is launched via tests/guest-debug/run-test.py > +# > + > +import gdb > +import sys > + > +failcount = 0 > + > +def report(cond, msg): > + "Report success/fail of test" > + if cond: > + print ("PASS: %s" % (msg)) > + else: > + print ("FAIL: %s" % (msg)) > + global failcount > + failcount += 1 > + > +def run_test(): > + "Run through the tests one by one" > + > + sym, ok = gdb.lookup_symbol("thread1_func") > + gdb.execute("b thread1_func") > + gdb.execute("c") > + > + frame = gdb.selected_frame() > + report(str(frame.function()) == "thread1_func", "break @ > %s"%frame) Does this actually check the correct thread is reported? > + > +# > +# This runs as the script it sourced (via -x, via run-test.py) > +# > +try: > + inferior = gdb.selected_inferior() > + arch = inferior.architecture() > + print("ATTACHED: %s" % arch.name()) > +except (gdb.error, AttributeError): > + print("SKIPPING (not connected)", file=sys.stderr) > + exit(0) > + > +if gdb.parse_and_eval('$pc') == 0: > + print("SKIP: PC not set") > + exit(0) > + > +try: > + # These are not very useful in scripts > + gdb.execute("set pagination off") > + gdb.execute("set confirm off") > + > + # Run the actual tests > + run_test() > +except (gdb.error): > + print ("GDB Exception: %s" % (sys.exc_info()[0])) > + failcount += 1 > + pass > + > +print("All tests complete: %d failures" % failcount) > +exit(failcount)
Pavel Labath <pavel@labath.sk> writes: > On 15/10/2021 17:59, Alex Bennée wrote: >> Pavel Labath <pavel@labath.sk> writes: >> >>> Ping. >>> >>> (This is my first qemu patch, so please let me know if I am doing >>> something wrong.) >> Apologies it slipped though the cracks. I shall have a look on >> Monday. >> > > I don't want to impose, but did this get buried over the weekend by > any chance? I had a quick look over and made some comments. I haven't been able to replicate the test manually so far but I might have broken tooling so I need to dig into that. > > regards, > pl
Thanks for taking a look. I've sent out a new version of the patch. Besides the Makefile change, I have also replaced the direct gdbserver_state manipulation with a call to gdb_set_stop_cpu. Further responses inline. On 19/10/2021 19:02, Alex Bennée wrote: > > Pavel Labath <pavel@labath.sk> writes: > >> Respond with Txxthread:yyyy; instead of a plain Sxx to indicate which >> thread received the signal. Otherwise, the debugger will associate it >> with the main one. Also automatically select this thread, as that is >> what gdb expects. >> >> Signed-off-by: Pavel Labath <pavel@labath.sk> >> --- >> gdbstub.c | 9 ++- >> tests/tcg/multiarch/Makefile.target | 7 +++ >> .../gdbstub/test-thread-breakpoint.py | 60 +++++++++++++++++++ >> 3 files changed, 74 insertions(+), 2 deletions(-) >> create mode 100644 tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py >> >> diff --git a/gdbstub.c b/gdbstub.c >> index 36b85aa..7bd4479 100644 >> --- a/gdbstub.c >> +++ b/gdbstub.c >> @@ -3138,8 +3138,13 @@ gdb_handlesig(CPUState *cpu, int sig) >> tb_flush(cpu); >> >> if (sig != 0) { >> - snprintf(buf, sizeof(buf), "S%02x", target_signal_to_gdb(sig)); >> - put_packet(buf); >> + gdbserver_state.c_cpu = cpu; >> + gdbserver_state.g_cpu = cpu; >> + g_string_printf(gdbserver_state.str_buf, >> + "T%02xthread:", target_signal_to_gdb(sig)); >> + gdb_append_thread_id(cpu, gdbserver_state.str_buf); >> + g_string_append_c(gdbserver_state.str_buf, ';'); >> + put_strbuf(); >> } >> /* put_packet() might have detected that the peer terminated the >> connection. */ >> diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target >> index 85a6fb7..c7b7e8b 100644 >> --- a/tests/tcg/multiarch/Makefile.target >> +++ b/tests/tcg/multiarch/Makefile.target >> @@ -73,6 +73,13 @@ run-gdbstub-qxfer-auxv-read: sha1 >> --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \ >> "basic gdbstub qXfer:auxv:read support") >> >> +run-gdbstub-thread-breakpoint: testthread >> + $(call run-test, $@, $(GDB_SCRIPT) \ >> + --gdb $(HAVE_GDB_BIN) \ >> + --qemu $(QEMU) --qargs "$(QEMU_OPTS)" \ >> + --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-thread-breakpoint.py, \ >> + "hitting a breakpoint on non-main thread") >> + > > You also need to add the test to EXTRA_RUNS here (or just bellow in fact). Done. > >> else >> run-gdbstub-%: >> $(call skip-test, "gdbstub test $*", "need working gdb") >> diff --git a/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py >> new file mode 100644 >> index 0000000..798d508 >> --- /dev/null >> +++ b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py >> @@ -0,0 +1,60 @@ >> +from __future__ import print_function >> +# >> +# Test auxiliary vector is loaded via gdbstub >> +# >> +# This is launched via tests/guest-debug/run-test.py >> +# >> + >> +import gdb >> +import sys >> + >> +failcount = 0 >> + >> +def report(cond, msg): >> + "Report success/fail of test" >> + if cond: >> + print ("PASS: %s" % (msg)) >> + else: >> + print ("FAIL: %s" % (msg)) >> + global failcount >> + failcount += 1 >> + >> +def run_test(): >> + "Run through the tests one by one" >> + >> + sym, ok = gdb.lookup_symbol("thread1_func") >> + gdb.execute("b thread1_func") >> + gdb.execute("c") >> + >> + frame = gdb.selected_frame() >> + report(str(frame.function()) == "thread1_func", "break @ >> %s"%frame) > > Does this actually check the correct thread is reported? It does it indirectly -- there is only one thread which can have thread1_func on the stack. If we do not report the correct thread, selected_frame() will point into the bowels of pthread_join, as that's where the main thread will be stuck at. I don't know of a direct way to check for the reported thread. gdb.selected_thread().name would be more direct, but I am not sure we would be able to correctly set the thread name on all supported platforms. > >> + >> +# >> +# This runs as the script it sourced (via -x, via run-test.py) >> +# >> +try: >> + inferior = gdb.selected_inferior() >> + arch = inferior.architecture() >> + print("ATTACHED: %s" % arch.name()) >> +except (gdb.error, AttributeError): >> + print("SKIPPING (not connected)", file=sys.stderr) >> + exit(0) >> + >> +if gdb.parse_and_eval('$pc') == 0: >> + print("SKIP: PC not set") >> + exit(0) >> + >> +try: >> + # These are not very useful in scripts >> + gdb.execute("set pagination off") >> + gdb.execute("set confirm off") >> + >> + # Run the actual tests >> + run_test() >> +except (gdb.error): >> + print ("GDB Exception: %s" % (sys.exc_info()[0])) >> + failcount += 1 >> + pass >> + >> +print("All tests complete: %d failures" % failcount) >> +exit(failcount) > >
diff --git a/gdbstub.c b/gdbstub.c index 36b85aa..7bd4479 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -3138,8 +3138,13 @@ gdb_handlesig(CPUState *cpu, int sig) tb_flush(cpu); if (sig != 0) { - snprintf(buf, sizeof(buf), "S%02x", target_signal_to_gdb(sig)); - put_packet(buf); + gdbserver_state.c_cpu = cpu; + gdbserver_state.g_cpu = cpu; + g_string_printf(gdbserver_state.str_buf, + "T%02xthread:", target_signal_to_gdb(sig)); + gdb_append_thread_id(cpu, gdbserver_state.str_buf); + g_string_append_c(gdbserver_state.str_buf, ';'); + put_strbuf(); } /* put_packet() might have detected that the peer terminated the connection. */ diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target index 85a6fb7..c7b7e8b 100644 --- a/tests/tcg/multiarch/Makefile.target +++ b/tests/tcg/multiarch/Makefile.target @@ -73,6 +73,13 @@ run-gdbstub-qxfer-auxv-read: sha1 --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \ "basic gdbstub qXfer:auxv:read support") +run-gdbstub-thread-breakpoint: testthread + $(call run-test, $@, $(GDB_SCRIPT) \ + --gdb $(HAVE_GDB_BIN) \ + --qemu $(QEMU) --qargs "$(QEMU_OPTS)" \ + --bin $< --test $(MULTIARCH_SRC)/gdbstub/test-thread-breakpoint.py, \ + "hitting a breakpoint on non-main thread") + else run-gdbstub-%: $(call skip-test, "gdbstub test $*", "need working gdb") diff --git a/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py new file mode 100644 index 0000000..798d508 --- /dev/null +++ b/tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py @@ -0,0 +1,60 @@ +from __future__ import print_function +# +# Test auxiliary vector is loaded via gdbstub +# +# This is launched via tests/guest-debug/run-test.py +# + +import gdb +import sys + +failcount = 0 + +def report(cond, msg): + "Report success/fail of test" + if cond: + print ("PASS: %s" % (msg)) + else: + print ("FAIL: %s" % (msg)) + global failcount + failcount += 1 + +def run_test(): + "Run through the tests one by one" + + sym, ok = gdb.lookup_symbol("thread1_func") + gdb.execute("b thread1_func") + gdb.execute("c") + + frame = gdb.selected_frame() + report(str(frame.function()) == "thread1_func", "break @ %s"%frame) + +# +# This runs as the script it sourced (via -x, via run-test.py) +# +try: + inferior = gdb.selected_inferior() + arch = inferior.architecture() + print("ATTACHED: %s" % arch.name()) +except (gdb.error, AttributeError): + print("SKIPPING (not connected)", file=sys.stderr) + exit(0) + +if gdb.parse_and_eval('$pc') == 0: + print("SKIP: PC not set") + exit(0) + +try: + # These are not very useful in scripts + gdb.execute("set pagination off") + gdb.execute("set confirm off") + + # Run the actual tests + run_test() +except (gdb.error): + print ("GDB Exception: %s" % (sys.exc_info()[0])) + failcount += 1 + pass + +print("All tests complete: %d failures" % failcount) +exit(failcount)
Respond with Txxthread:yyyy; instead of a plain Sxx to indicate which thread received the signal. Otherwise, the debugger will associate it with the main one. Also automatically select this thread, as that is what gdb expects. Signed-off-by: Pavel Labath <pavel@labath.sk> --- gdbstub.c | 9 ++- tests/tcg/multiarch/Makefile.target | 7 +++ .../gdbstub/test-thread-breakpoint.py | 60 +++++++++++++++++++ 3 files changed, 74 insertions(+), 2 deletions(-) create mode 100644 tests/tcg/multiarch/gdbstub/test-thread-breakpoint.py