1# This testcase is part of GDB, the GNU debugger.
2#
3# Copyright 2013-2020 Free Software Foundation, Inc.
4#
5# This program is free software; you can redistribute it and/or modify
6# it under the terms of the GNU General Public License as published by
7# the Free Software Foundation; either version 3 of the License, or
8# (at your option) any later version.
9#
10# This program is distributed in the hope that it will be useful,
11# but WITHOUT ANY WARRANTY; without even the implied warranty of
12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13# GNU General Public License for more details.
14#
15# You should have received a copy of the GNU General Public License
16# along with this program.  If not, see <http://www.gnu.org/licenses/>.
17
18# Regression test for a bug that would go like this:
19#
20# - Run to a breakpoint that is hit by two threads (A and B)
21#   simultaneously.
22#
23# - One of the breakpoint hits is processed (e.g., thread A) and
24#   causes a user-visible stop.  The other (thread B) is left pending.
25#
26# - The user deletes the breakpoint with "del", which causes a
27#   confirmation query.
28#
29# - By mistake, that would result in the target being left with async
30#   enabled, even though it wasn't to begin with.
31#
32# - GDB reacts to target async enablement by polling for target
33#   events.  As no thread is resumed the target replies
34#   TARGET_WAITKIND_NO_RESUMED.
35#
36# - The user continues the program, expecting it to exit.  The thread
37#   that has an event pending (thread B) is not really resumed.
38#
39# - But, nothing signals the event loop that there's a pending event
40#   waiting to be collected for thread B, so that event is never
41#   processed, thread B is never resumed and the program never exits.
42#
43# Ref: https://sourceware.org/ml/gdb-patches/2015-01/msg00592.html
44
45standard_testfile
46
47if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] == -1} {
48    return -1
49}
50
51proc test {} {
52    global srcfile gdb_prompt
53
54    if ![runto_main] {
55	return -1
56    }
57
58    delete_breakpoints
59
60    set bp_line [gdb_get_line_number "set break here" $srcfile]
61
62    gdb_breakpoint "break_function"
63    gdb_continue_to_breakpoint "cont to break_function" ".*$srcfile:$bp_line\r\n.*"
64
65    # Do something that causes a query/secondary prompt.
66
67    set test "delete breakpoints, answer prompt"
68    set saw_prompt 0
69    gdb_test_multiple "delete breakpoints" $test {
70	-re "Delete all breakpoints.*y or n.*$" {
71	    set saw_prompt 1
72	    send_gdb "y\n"
73	    exp_continue
74	}
75	-re "$gdb_prompt $" {
76	    gdb_assert $saw_prompt $test
77	}
78    }
79
80    gdb_continue_to_end "" "continue" 1
81}
82
83# Test a few times to make sure an event is left pending.  At the time
84# of writing, the bug always triggers, but that might naturally depend
85# on machine.
86for {set i 1} {$i <= 10} {incr i} {
87    with_test_prefix "iter $i" {
88	test
89    }
90}
91