12ab52e977
With the test changed as in the patch, against current mainline, we get:
(gdb) PASS: gdb.ada/tasks.exp: info tasks before inserting breakpoint
break break_me task 1
Breakpoint 2 at 0x4030b0: file /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.ada/tasks/foo.adb, line 27.
(gdb) PASS: gdb.ada/tasks.exp: break break_me task 1
break break_me task 3
Note: breakpoint 2 also set at pc 0x4030b0.
Breakpoint 3 at 0x4030b0: file /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.ada/tasks/foo.adb, line 27.
(gdb) PASS: gdb.ada/tasks.exp: break break_me task 3
continue
Continuing.
[Switching to Thread 0x7ffff7dc7700 (LWP 27133)]
Breakpoint 2, foo.break_me () at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.ada/tasks/foo.adb:27
27 null;
(gdb) FAIL: gdb.ada/tasks.exp: continue to breakpoint
info tasks
ID TID P-ID Pri State Name
1 63b010 48 Waiting on RV with 3 main_task
2 63bd80 1 48 Accept or Select Term task_list(1)
* 3 63f510 1 48 Accepting RV with 1 task_list(2)
4 642ca0 1 48 Accept or Select Term task_list(3)
(gdb) PASS: gdb.ada/tasks.exp: info tasks after hitting breakpoint
The breakpoint that caused a stop is breakpoint 3, but GDB end up
reporting (and running breakpoint commands of) "Breakpoint 2" instead.
The issue is that the bpstat_check_breakpoint_conditions logic of
"wrong thread" is missing the "wrong task" check. This is usually
harmless, because the thread hop code in infrun.c code that handles
wrong-task-hitting-breakpoint does check for task-specific breakpoints
(within breakpoint_thread_match):
/* Check if a regular breakpoint has been hit before checking
for a potential single step breakpoint. Otherwise, GDB will
not see this breakpoint hit when stepping onto breakpoints. */
if (regular_breakpoint_inserted_here_p (aspace, stop_pc))
{
if (!breakpoint_thread_match (aspace, stop_pc, ecs->ptid))
thread_hop_needed = 1;
}
IOW, usually, when one only has a task specific breakpoint at a given
address, things work correctly. Put another task-specific or
non-task-specific breakpoint there, and things break.
A patch that eliminates the special thread hop code in infrun.c is
what exposed this, as after that GDB solely relies on
bpstat_check_breakpoint_conditions to know whether the right or wrong
task hit a breakpoint. IOW, given the latent bug, Ada task-specific
breakpoints become non-task-specific, and that is caught by the
testsuite, as:
break break_me task 3
Breakpoint 2 at 0x4030b0: file /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.ada/tasks/foo.adb, line 27.
(gdb) PASS: gdb.ada/tasks.exp: break break_me task 3
continue
Continuing.
[Switching to Thread 0x7ffff7fcb700 (LWP 17122)]
Breakpoint 2, foo.break_me () at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.ada/tasks/foo.adb:27
27 null;
(gdb) PASS: gdb.ada/tasks.exp: continue to breakpoint
info tasks
ID TID P-ID Pri State Name
1 63b010 48 Waiting on RV with 2 main_task
* 2 63bd80 1 48 Accepting RV with 1 task_list(1)
3 63f510 1 48 Accept or Select Term task_list(2)
4 642ca0 1 48 Accept or Select Term task_list(3)
(gdb) FAIL: gdb.ada/tasks.exp: info tasks after hitting breakpoint
It was after seeing this that I thought of how to expose the bug with
current mainline.
Tested on x86_64 Fedora 17.
gdb/
2014-02-26 Pedro Alves <palves@redhat.com>
* breakpoint.c (bpstat_check_breakpoint_conditions): Handle
task-specific breakpoints.
gdb/testsuite/
2014-02-26 Pedro Alves <palves@redhat.com>
* gdb.ada/tasks.exp: Set a task-specific breakpoint at break_me
that won't ever trigger. Make sure that GDB reports the correct
breakpoint that caused the stop.
85 lines
3.1 KiB
Text
85 lines
3.1 KiB
Text
# Copyright 2009-2014 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/>.
|
|
|
|
load_lib "ada.exp"
|
|
|
|
standard_ada_testfile foo
|
|
|
|
if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug ]] != "" } {
|
|
return -1
|
|
}
|
|
|
|
clean_restart ${testfile}
|
|
|
|
set bp_location [gdb_get_line_number "STOP_HERE" ${testdir}/foo.adb]
|
|
runto "foo.adb:$bp_location"
|
|
|
|
# Make sure that all tasks appear in the "info tasks" listing, and
|
|
# that the active task is the environment task.
|
|
gdb_test "info tasks" \
|
|
[join {" +ID +TID P-ID Pri State +Name" \
|
|
"\\* +1 .* main_task" \
|
|
" +2 .* task_list\\(1\\)" \
|
|
" +3 .* task_list\\(2\\)" \
|
|
" +4 .* task_list\\(3\\)"} \
|
|
"\r\n"] \
|
|
"info tasks before inserting breakpoint"
|
|
|
|
# Insert a breakpoint that should stop only if task 1 stops. Since
|
|
# task 1 never calls break_me, this shouldn't actually ever trigger.
|
|
# The fact that this breakpoint is created _before_ the next one
|
|
# matters. GDB used to have a bug where it would report the first
|
|
# breakpoint in the list that matched the triggered-breakpoint's
|
|
# address, no matter which task it was specific to.
|
|
gdb_test "break break_me task 1" "Breakpoint .* at .*"
|
|
|
|
# Now, insert a breakpoint that should stop only if task 3 stops, and
|
|
# extract its number.
|
|
set bp_number -1
|
|
set test "break break_me task 3"
|
|
gdb_test_multiple $test $test {
|
|
-re "Breakpoint (.*) at .*$gdb_prompt $" {
|
|
set bp_number $expect_out(1,string)
|
|
pass $test
|
|
}
|
|
}
|
|
|
|
if {$bp_number < 0} {
|
|
return
|
|
}
|
|
|
|
# Continue to that breakpoint. Task 2 should hit it first, and GDB
|
|
# is expected to ignore that hit and resume the execution. Only then
|
|
# task 3 will hit our breakpoint, and GDB is expected to stop at that
|
|
# point. Also make sure that GDB reports the correct breakpoint number.
|
|
gdb_test "continue" \
|
|
".*Breakpoint $bp_number, foo.break_me \\(\\).*" \
|
|
"continue to breakpoint"
|
|
|
|
# Check that it is indeed task 3 that hit the breakpoint by checking
|
|
# which is the active task.
|
|
gdb_test "info tasks" \
|
|
[join {" +ID +TID P-ID Pri State +Name" \
|
|
" +1 .* main_task" \
|
|
" +2 .* task_list\\(1\\)" \
|
|
"\\* +3 .* task_list\\(2\\)" \
|
|
" +4 .* task_list\\(3\\)"} \
|
|
"\r\n"] \
|
|
"info tasks after hitting breakpoint"
|
|
|
|
# Now, resume the execution and make sure that GDB does not stop when
|
|
# task 4 hits the breakpoint. Continuing thus results in our program
|
|
# running to completion.
|
|
gdb_continue_to_end "" continue 1
|