Re: [PATCH v3] gdb/testsuite: add test for backtracing for threaded inferiors from a corefile

[Luis Machado <luis.machado@arm.com>]

On 11/24/23 12:26, Luis Machado wrote:
> On 10/25/23 12:42, Guinevere Larsen wrote:
>> This patch is based on an out-of-tree patch that fedora has been
>> carrying for a while. It tests if GDB is able to properly unwind a
>> threaded program in the following situations:
>> * regular threads
>> * in a signal handler
>> * in a signal handler executing on an alternate stack
>>
>> And the final frame can either be in a syscall or in an infinite loop.
>>
>> The test works by running the inferior until a crash to generate a
>> corefile, or until right before the crash. Then applies a backtrace to
>> all threads to see if any frame can't be identified, and the order of
>> the threads in GDB. Finally, it goes thread by thread and tries to
>> collect a large part of the backtrace, to confirm that everything is
>> being unwound correctly.
>>
>> Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
>> ---
>>
>> Changes for v3:
>> * Resolved Lancelot's comment
>> * undid early exit in favor of more readable gdb_test usage to load the
>>   corefile
>>
>> Changes for v2:
>> * Linaro CI identified an issue with the test, which made the test fail
>>   when using read1. Fixed here
>> * Also added early exit on corefile tests, if the corefile isn't
>>   properly loaded
>>
>> ---
>>  gdb/testsuite/gdb.threads/threadcrash.c   | 443 ++++++++++++++++++++++
>>  gdb/testsuite/gdb.threads/threadcrash.exp | 209 ++++++++++
>>  2 files changed, 652 insertions(+)
>>  create mode 100644 gdb/testsuite/gdb.threads/threadcrash.c
>>  create mode 100644 gdb/testsuite/gdb.threads/threadcrash.exp
>>
>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.c b/gdb/testsuite/gdb.threads/threadcrash.c
>> new file mode 100644
>> index 00000000000..e476ae7b07d
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.threads/threadcrash.c
>> @@ -0,0 +1,443 @@
>> +/* This testcase is part of GDB, the GNU debugger.
>> +
>> +   Copyright 2023 Free Software Foundation, Inc.
>> +
>> +   This program is free software; you can redistribute it and/or modify
>> +   it under the terms of the GNU General Public License as published by
>> +   the Free Software Foundation; either version 3 of the License, or
>> +   (at your option) any later version.
>> +
>> +   This program is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> +   GNU General Public License for more details.
>> +
>> +   You should have received a copy of the GNU General Public License
>> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <pthread.h>
>> +#include <assert.h>
>> +#include <stdlib.h>
>> +#include <signal.h>
>> +#include <unistd.h>
>> +
>> +/* The delay that the main thread gives once all the worker threads have
>> +   reached the barrier before the main thread enters the function on which
>> +   GDB will have placed a breakpoint.  */
>> +
>> +#define MAIN_THREAD_DELAY 2
>> +
>> +/* The maximum time we allow this test program to run for before an alarm
>> +   signal is sent and everything will exit.  */
>> +#define WATCHDOG_ALARM_TIME 600
>> +
>> +/* Aliases for the signals used within this script.  Each signal
>> +   corresponds to an action (from the FINAL_ACTION enum) that the signal
>> +   handler will perform.  */
>> +
>> +#define SPIN_SIGNAL SIGUSR1
>> +#define SYSCALL_SIGNAL SIGUSR2
>> +
>> +/* Describe the final action that a thread should perform.  */
>> +
>> +enum final_action
>> +  {
>> +    /* Thread should spin in an infinite loop.  */
>> +    SPIN = 0,
>> +
>> +    /* Thread should block in a syscall.  */
>> +    SYSCALL,
>> +
>> +    /* This is just a marker to allow for looping over the enum.  */
>> +    LAST_ACTION
>> +  };
>> +
>> +/* Where should the thread perform this action?  */
>> +
>> +enum exec_location
>> +  {
>> +    /* Just a normal thread, on a normal stack.  */
>> +    NORMAL = 0,
>> +
>> +    /* In a signal handler, but use the normal stack.  */
>> +    SIGNAL_HANDLER,
>> +
>> +    /* In a signal handler using an alternative stack.  */
>> +    SIGNAL_ALT_STACK,
>> +
>> +    /* This is just a marker to allow for looping over the enum.  */
>> +    LAST_LOCACTION
>> +  };
>> +
>> +/* A descriptor for a single thread job.  We create a new thread for each
>> +   job_description.  */
>> +
>> +struct job_description
>> +{
>> +  /* What action should this thread perform.  */
>> +  enum final_action action;
>> +
>> +  /* Where should the thread perform the action.  */
>> +  enum exec_location location;
>> +
>> +  /* The actual thread handle, so we can join with the thread.  */
>> +  pthread_t thread;
>> +};
>> +
>> +/* A pthread barrier, used to (try) and synchronise the threads.  */
>> +pthread_barrier_t global_barrier;
>> +
>> +/* Return a list of jobs, and place the length of the list in *COUNT.  */
>> +
>> +struct job_description *
>> +get_job_list (int *count)
>> +{
>> +  /* The number of jobs.  */
>> +  int num = LAST_ACTION * LAST_LOCACTION;
>> +
>> +  /* The uninitialised array of jobs.  */
>> +  struct job_description *list
>> +    = malloc (num * sizeof (struct job_description));
>> +  assert (list != NULL);
>> +
>> +  /* Fill the array with all possible jobs.  */
>> +  for (int i = 0; i < (int) LAST_ACTION; ++i)
>> +    for (int j = 0; j < (int) LAST_LOCACTION; ++j)
>> +      {
>> +	int idx = (i * LAST_LOCACTION) + j;
>> +	list[idx].action = (enum final_action) i;
>> +	list[idx].location = (enum exec_location) j;
>> +      }
>> +
>> +  /* Return the array of jobs.  */
>> +  *count = num;
>> +  return list;
>> +}
>> +
>> +/* This function should never be called.  If it is then an assertion will
>> +   trigger.  */
>> +
>> +void
>> +assert_not_reached (void)
>> +{
>> +  assert (0);
>> +}
>> +
>> +/* The function for a SPIN action.  Just spins in a loop.  The LOCATION
>> +   argument exists so GDB can identify the expected context for this
>> +   function.  */
>> +
>> +void
>> +do_spin_task (enum exec_location location)
>> +{
>> +  (void) location;
>> +
>> +  /* Let everyone know that we're about to perform our action.  */
>> +  int res = pthread_barrier_wait (&global_barrier);
>> +  assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> +  while (1)
>> +    {
>> +      /* Nothing.  */
>> +    }
>> +}
>> +
>> +/* The function for a SYSCALL action.  Just spins in a loop.  The LOCATION
>> +   argument exists so GDB can identify the expected context for this
>> +   function.  */
>> +
>> +void
>> +do_syscall_task (enum exec_location location)
>> +{
>> +  (void) location;
>> +
>> +  /* Let everyone know that we're about to perform our action.  */
>> +  int res = pthread_barrier_wait (&global_barrier);
>> +  assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> +  sleep (600);
>> +}
>> +
>> +/* Return the required size for a sigaltstack.  We start with a single
>> +   page, but do check against the system defined minimums.  We don't run
>> +   much on the alternative stacks, so we don't need a huge one.  */
>> +
>> +size_t
>> +get_stack_size (void)
>> +{
>> +  size_t size = getpagesize ();	/* Arbitrary starting size.  */
>> +  if (size < SIGSTKSZ)
>> +    size = SIGSTKSZ;
>> +  if (size < MINSIGSTKSZ)
>> +    size = MINSIGSTKSZ;
>> +  return size;
>> +}
>> +
>> +/* A descriptor for an alternative stack.  */
>> +
>> +struct stack_descriptor
>> +{
>> +  /* The base address of the alternative stack.  This is the address that
>> +     must be freed to release the memory used by this stack.  */
>> +  void *base;
>> +
>> +  /* The size of this alternative stack.  Tracked just so we can query this
>> +     from GDB.  */
>> +  size_t size;
>> +};
>> +
>> +/* Install an alternative signal stack.  Return a descriptor for the newly
>> +   allocated alternative stack.  */
>> +
>> +struct stack_descriptor
>> +setup_alt_stack (void)
>> +{
>> +  size_t stack_size = get_stack_size ();
>> +
>> +  void *stack_area = malloc (stack_size);
>> +
>> +  stack_t stk;
>> +  stk.ss_sp = stack_area;
>> +  stk.ss_flags = 0;
>> +  stk.ss_size = stack_size;
>> +
>> +  int res = sigaltstack (&stk, NULL);
>> +  assert (res == 0);
>> +
>> +  struct stack_descriptor desc;
>> +  desc.base = stack_area;
>> +  desc.size = stack_size;
>> +
>> +  return desc;
>> +}
>> +
>> +/* Return true (non-zero) if we are currently on the alternative stack,
>> +   otherwise, return false (zero).  */
>> +
>> +int
>> +on_alt_stack_p (void)
>> +{
>> +  stack_t stk;
>> +  int res = sigaltstack (NULL, &stk);
>> +  assert (res == 0);
>> +
>> +  return (stk.ss_flags & SS_ONSTACK) != 0;
>> +}
>> +
>> +/* The signal handler function.  All signals call here, so we use SIGNO
>> +   (the signal that was delivered) to decide what action to perform.  This
>> +   function might, or might not, have been called on an alternative signal
>> +   stack.  */
>> +
>> +void
>> +signal_handler (int signo)
>> +{
>> +  enum exec_location location
>> +    = on_alt_stack_p () ? SIGNAL_ALT_STACK : SIGNAL_HANDLER;
>> +
>> +  switch (signo)
>> +    {
>> +    case SPIN_SIGNAL:
>> +      do_spin_task (location);
>> +      break;
>> +
>> +    case SYSCALL_SIGNAL:
>> +      do_syscall_task (location);
>> +      break;
>> +
>> +    default:
>> +      assert_not_reached ();
>> +    }
>> +}
>> +
>> +/* The thread worker function.  ARG is a job_description pointer which
>> +   describes what this thread is expected to do.  This function always
>> +   returns a NULL pointer.  */
>> +
>> +void *
>> +thread_function (void *arg)
>> +{
>> +  struct job_description *job = (struct job_description *) arg;
>> +  struct stack_descriptor desc = { NULL, 0 };
>> +  int sa_flags = 0;
>> +
>> +  switch (job->location)
>> +    {
>> +    case NORMAL:
>> +      /* This thread performs the worker action on the current thread,
>> +	 select the correct worker function based on the requested
>> +	 action.  */
>> +      switch (job->action)
>> +	{
>> +	case SPIN:
>> +	  do_spin_task (NORMAL);
>> +	  break;
>> +
>> +	case SYSCALL:
>> +	  do_syscall_task (NORMAL);
>> +	  break;
>> +
>> +	default:
>> +	  assert_not_reached ();
>> +	}
>> +      break;
>> +
>> +    case SIGNAL_ALT_STACK:
>> +      /* This thread is to perform its action in a signal handler on the
>> +	 alternative stack.  Install the alternative stack now, and then
>> +	 fall through to the normal signal handler location code.  */
>> +      desc = setup_alt_stack ();
>> +      assert (desc.base != NULL);
>> +      assert (desc.size > 0);
>> +      sa_flags = SA_ONSTACK;
>> +
>> +      /* Fall through.  */
>> +    case SIGNAL_HANDLER:
>> +      {
>> +	/* This thread is to perform its action in a signal handler.  We
>> +	   might have just installed an alternative signal stack.  */
>> +	int signo, res;
>> +
>> +	/* Select the correct signal number so that the signal handler will
>> +	   perform the required action.  */
>> +	switch (job->action)
>> +	  {
>> +	  case SPIN:
>> +	    signo = SPIN_SIGNAL;
>> +	    break;
>> +
>> +	  case SYSCALL:
>> +	    signo = SYSCALL_SIGNAL;
>> +	    break;
>> +
>> +	  default:
>> +	    assert_not_reached ();
>> +	  }
>> +
>> +	/* Now setup the signal handler.  */
>> +	struct sigaction sa;
>> +	sa.sa_handler = signal_handler;
>> +	sigfillset (&sa.sa_mask);
>> +	sa.sa_flags = sa_flags;
>> +	res = sigaction (signo, &sa, NULL);
>> +	assert (res == 0);
>> +
>> +	/* Send the signal to this thread.  */
>> +	res = pthread_kill (job->thread, signo);
>> +	assert (res == 0);
>> +      }
>> +      break;
>> +
>> +    default:
>> +      assert_not_reached ();
>> +    };
>> +
>> +  /* Free the alt-stack if we allocated one, if not DESC.BASE will be
>> +     NULL so this call is fine.  */
>> +  free (desc.base);
>> +
>> +  /* Thread complete.  */
>> +  return NULL;
>> +}
>> +
>> +void
>> +start_job (struct job_description *job)
>> +{
>> +  int res;
>> +
>> +  res = pthread_create (&job->thread, NULL, thread_function, job);
>> +  assert (res == 0);
>> +}
>> +
>> +/* Join with the thread for JOB.  This will block until the thread for JOB
>> +   has finished.  */
>> +
>> +void
>> +finalise_job (struct job_description *job)
>> +{
>> +  int res;
>> +  void *retval;
>> +
>> +  res = pthread_join (job->thread, &retval);
>> +  assert (res == 0);
>> +  assert (retval == NULL);
>> +}
>> +
>> +/* Function that GDB can place a breakpoint on.  */
>> +
>> +void
>> +breakpt (void)
>> +{
>> +  /* Nothing.  */
>> +}
>> +
>> +/* Function that triggers a crash, if the user has setup their environment
>> +   correctly this will dump a core file, which GDB can then examine.  */
>> +
>> +void
>> +crash_function (void)
>> +{
>> +  volatile int *p = 0;
>> +  volatile int n = *p;
>> +  (void) n;
>> +}
>> +
>> +/* Entry point.  */
>> +
>> +int
>> +main ()
>> +{
>> +  int job_count, res;
>> +  struct job_description *jobs = get_job_list (&job_count);
>> +
>> +  /* This test is going to park some threads inside infinite loops.  Just
>> +     in case this program is left running, install an alarm that will cause
>> +     everything to exit.  */
>> +  alarm (WATCHDOG_ALARM_TIME);
>> +
>> +  /* We want each worker thread (of which there are JOB_COUNT) plus the
>> +     main thread (hence + 1) to wait at the barrier.  */
>> +  res = pthread_barrier_init (&global_barrier, NULL, job_count + 1);
>> +  assert (res == 0);
>> +
>> +  /* Start all the jobs.  */
>> +  for (int i = 0; i < job_count; ++i)
>> +    start_job (&jobs[i]);
>> +
>> +  /* Notify all the worker threads that we're waiting for them.  */
>> +  res = pthread_barrier_wait (&global_barrier);
>> +  assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> +  /* All we know at this point is that all the worker threads have reached
>> +     the barrier, which is just before they perform their action.  But we
>> +     really want them to start their action.
>> +
>> +     There's really no way we can be 100% certain that the worker threads
>> +     have started their action, all we can do is wait for a short while and
>> +     hope that the machine we're running on is not too slow.  */
>> +  sleep (MAIN_THREAD_DELAY);
>> +
>> +  /* A function that GDB can place a breakpoint on.  By the time we get
>> +     here we are as sure as we can be that all of the worker threads have
>> +     started and are in their worker action (spinning, or syscall).  */
>> +  breakpt ();
>> +
>> +  /* If GDB is not attached then this function will cause a crash, which
>> +     can be used to dump a core file, which GDB can then analyse.  */
>> +  crash_function ();
>> +
>> +  /* Due to the crash we never expect to get here.  Plus the worker actions
>> +     never terminate.  But for completeness, here's where we join with all
>> +     the worker threads.  */
>> +  for (int i = 0; i < job_count; ++i)
>> +    finalise_job (&jobs[i]);
>> +
>> +  /* Cleanup the barrier.  */
>> +  res = pthread_barrier_destroy (&global_barrier);
>> +  assert (res == 0);
>> +
>> +  /* And clean up the jobs list.  */
>> +  free (jobs);
>> +
>> +  return 0;
>> +}
>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp b/gdb/testsuite/gdb.threads/threadcrash.exp
>> new file mode 100644
>> index 00000000000..ee81b5c32f2
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.threads/threadcrash.exp
>> @@ -0,0 +1,209 @@
>> +# This testcase is part of GDB, the GNU debugger.
>> +
>> +# Copyright 2023 Free Software Foundation, Inc.
>> +
>> +# This program is free software; you can redistribute it and/or modify
>> +# it under the terms of the GNU General Public License as published by
>> +# the Free Software Foundation; either version 3 of the License, or
>> +# (at your option) any later version.
>> +#
>> +# This program is distributed in the hope that it will be useful,
>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> +# GNU General Public License for more details.
>> +#
>> +# You should have received a copy of the GNU General Public License
>> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> +
>> +# This test case looks at GDB's ability to get correct backtraces for a
>> +# crashed inferior, recreating it from a live inferior, a corefile and
>> +# a gcore.
>> +
>> +
>> +# First check that we have 7 threads.
>> +
>> +proc test_thread_count {} {
>> +    set thread_count 0
>> +
>> +    gdb_test_multiple "info threads" "getting thread count" -lbl {
>> +	-re "Thread" {
>> +	    incr thread_count
>> +	    exp_continue
>> +	}
>> +	-re "$::gdb_prompt " {
>> +	    gdb_assert {$thread_count == 7}
>> +	}
>> +    }
>> +
>> +    return $thread_count
>> +}
>> +
>> +# Apply all to quickly check if all expected states are
>> +# present.  Then, save the full desired backtrace in a list
>> +# so we can check full backtraces later.
>> +
>> +proc thread_apply_all {} {
>> +    global test_list
>> +
>> +    set unwind_fail false
>> +
>> +    gdb_test_multiple "thread apply all backtrace" \
>> +	"Get thread information" -lbl {
>> +	    -re "#\[0-9\]+\\\?\\\?\[^\n\]*" {
>> +		set unwind_fail true
>> +		exp_continue
>> +	    }
>> +	    -re "\[^\n\]*syscall_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>> +		set test_list [linsert $test_list end [multi_line ".*sleep.*" \
>> +					      ".*do_syscall_task .location=SIGNAL_ALT_STACK.*" \
>> +					      ".*signal_handler.*" \
>> +					      ".*signal handler called.*" \
>> +					      ".*pthread_kill.*" \
>> +					      ".*thread_function.*"]]
>> +		exp_continue
>> +	    }
>> +	    -re "\[^\n\]*syscall_task .location=SIGNAL_HANDLER\[^\n\]*" {
>> +		set test_list [linsert $test_list end [multi_line ".*sleep.*" \
>> +					      ".*do_syscall_task .location=SIGNAL_HANDLER.*" \
>> +					      ".*signal_handler.*" \
>> +					      ".*signal handler called.*" \
>> +					      ".*pthread_kill.*" \
>> +					      ".*thread_function.*"]]
>> +		exp_continue
>> +	    }
>> +	    -re "\[^\n\]*syscall_task .location=NORMAL\[^\n\]*" {
>> +		set test_list [linsert $test_list end [multi_line ".*sleep.*" \
>> +					      ".*do_syscall_task .location=NORMAL.*" \
>> +					      ".*thread_function.*"]]
>> +		exp_continue
>> +	    }
>> +	    -re "\[^\n\]*spin_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>> +		set test_list [linsert $test_list end [multi_line ".*do_spin_task .location=SIGNAL_ALT_STACK.*" \
>> +					      ".*signal_handler.*" \
>> +					      ".*signal handler called.*" \
>> +					      ".*pthread_kill.*" \
>> +					      ".*thread_function.*"]]
>> +		exp_continue
>> +	    }
>> +	    -re "\[^\n\]*spin_task .location=SIGNAL_HANDLER\[^\n\]*" {
>> +		set test_list [linsert $test_list end [multi_line ".*do_spin_task .location=SIGNAL_HANDLER.*" \
>> +					      ".*signal_handler.*" \
>> +					      ".*signal handler called.*" \
>> +					      ".*pthread_kill.*" \
>> +					      ".*thread_function.*"]]
>> +		exp_continue
>> +	    }
>> +	    -re "\[^\n\]*spin_task .location=NORMAL\[^\n\]*" {
>> +		set test_list [linsert $test_list end [multi_line ".*do_spin_task .location=NORMAL..*" \
>> +					      ".*thread_function.*"]]
>> +		exp_continue
>> +	    }
>> +	    -re "\[^\n\]*main\[^\n\]*" {
>> +		set test_list [linsert $test_list end ".*main.*"]
>> +		exp_continue
>> +	    }
>> +	    -re "$::gdb_prompt " {
>> +		pass $gdb_test_name
>> +	    }
>> +    }
>> +
>> +    gdb_assert {$unwind_fail == false}
>> +}
>> +
>> +proc do_full_test {} {
>> +    global test_list
>> +    set thread_count [test_thread_count]
>> +
>> +    thread_apply_all
>> +
>> +    gdb_assert {$thread_count == [llength $test_list]}
>> +
>> +    for {set i 0} {$i < $thread_count } {incr i} {
>> +	set thread_num [expr [llength $test_list] - $i]
>> +
>> +	gdb_test "thread apply $thread_num backtrace" [lindex $test_list $i]
>> +    }
>> +}
>> +
>> +proc_with_prefix test_corefile {} {
>> +    set corefile [core_find $::binfile]
>> +    if { $corefile == "" } {
>> +	untested "couldn't generate corefile"
>> +	return
>> +    }
>> +    set corefile [gdb_remote_download host $corefile]
>> +
>> +    gdb_test "core-file $corefile" \
>> +	     "" \
>> +	     "loading_corefile" \
>> +	     "A program is being debugged already\\\.  Kill it\\\? \\\(y or n\\\) " \
>> +	     "y"
>> +
>> +    do_full_test
>> +}
>> +
>> +proc_with_prefix test_gcore {} {
>> +
>> +    clean_restart "$::binfile"
>> +
>> +    gdb_test "handle SIGUSR1 nostop print pass" \
>> +	".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>> +	"setup SIGUSR1"
>> +    gdb_test "handle SIGUSR2 nostop print pass" \
>> +	".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>> +	"setup SIGUSR2"
>> +
>> +    gdb_test "run" ".*Segmentation fault.*" "continue to crash"
>> +
>> +    set gcore_name "${::binfile}.gcore"
>> +    set gcore_supported [gdb_gcore_cmd "$gcore_name" "saving gcore"]
>> +
>> +    if {!$gcore_supported} {
>> +	unsupported "couldn't generate gcore file"
>> +	return
>> +    }
>> +
>> +    set corefile [gdb_remote_download host $gcore_name]
>> +
>> +    gdb_test "core-file $corefile" \
>> +	     "" \
>> +	     "loading_corefile" \
>> +	     "A program is being debugged already\\\.  Kill it\\\? \\\(y or n\\\) " \
>> +	     "y"
>> +
>> +    do_full_test
>> +}
>> +
>> +standard_testfile
>> +
>> +if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
>> +    return -1
>> +}
>> +
>> +clean_restart ${binfile}
>> +
>> +gdb_test_no_output "set backtrace limit unlimited"
>> +
>> +set test_list { }
>> +
>> +with_test_prefix "live inferior" {
>> +    gdb_test "handle SIGUSR1 nostop print pass" \
>> +	".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>> +	"setup SIGUSR1"
>> +    gdb_test "handle SIGUSR2 nostop print pass" \
>> +	".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>> +	"setup SIGUSR2"
>> +
>> +    gdb_breakpoint "breakpt"
>> +    gdb_test "run" ".*breakpt.*" "run to break function"
>> +
>> +    do_full_test
>> +}
>> +
>> +set test_list { }
>> +
>> +test_corefile
>> +
>> +set test_list { }
>> +
>> +test_gcore
> 
> I gave this a try on aarch64-linux arm-linux and it works as expected.
> 
> Unless others have further objections, I think this looks good.
> 
> Reviewed-By:  Luis Machado  <luis.machado@arm.com>


Just to complement, a small nit about the current patch is that it throws an ERROR when running the
testsuite using the native-gdbserver board.

ERROR: gdbserver does not support run without extended-remote
    while executing
"error "gdbserver does not support $command without extended-remote""

Maybe we should punt when testing against native-gdbserver, or start the program differently.