forked from Imagelibrary/binutils-gdb
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.
86 lines
3.1 KiB
Plaintext
86 lines
3.1 KiB
Plaintext
# Copyright 2009-2014 Free Software Foundation, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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load_lib "ada.exp"
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standard_ada_testfile foo
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if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug ]] != "" } {
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return -1
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}
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clean_restart ${testfile}
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set bp_location [gdb_get_line_number "STOP_HERE" ${testdir}/foo.adb]
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runto "foo.adb:$bp_location"
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# Make sure that all tasks appear in the "info tasks" listing, and
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# that the active task is the environment task.
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gdb_test "info tasks" \
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[join {" +ID +TID P-ID Pri State +Name" \
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"\\* +1 .* main_task" \
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" +2 .* task_list\\(1\\)" \
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" +3 .* task_list\\(2\\)" \
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" +4 .* task_list\\(3\\)"} \
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"\r\n"] \
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"info tasks before inserting breakpoint"
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# Insert a breakpoint that should stop only if task 1 stops. Since
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# task 1 never calls break_me, this shouldn't actually ever trigger.
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# The fact that this breakpoint is created _before_ the next one
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# matters. GDB used to have a bug where it would report the first
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# breakpoint in the list that matched the triggered-breakpoint's
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# address, no matter which task it was specific to.
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gdb_test "break break_me task 1" "Breakpoint .* at .*"
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# Now, insert a breakpoint that should stop only if task 3 stops, and
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# extract its number.
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set bp_number -1
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set test "break break_me task 3"
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gdb_test_multiple $test $test {
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-re "Breakpoint (.*) at .*$gdb_prompt $" {
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set bp_number $expect_out(1,string)
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pass $test
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}
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}
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if {$bp_number < 0} {
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return
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}
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# Continue to that breakpoint. Task 2 should hit it first, and GDB
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# is expected to ignore that hit and resume the execution. Only then
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# task 3 will hit our breakpoint, and GDB is expected to stop at that
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# point. Also make sure that GDB reports the correct breakpoint number.
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gdb_test "continue" \
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".*Breakpoint $bp_number, foo.break_me \\(\\).*" \
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"continue to breakpoint"
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# Check that it is indeed task 3 that hit the breakpoint by checking
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# which is the active task.
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gdb_test "info tasks" \
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[join {" +ID +TID P-ID Pri State +Name" \
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" +1 .* main_task" \
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" +2 .* task_list\\(1\\)" \
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"\\* +3 .* task_list\\(2\\)" \
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" +4 .* task_list\\(3\\)"} \
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"\r\n"] \
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"info tasks after hitting breakpoint"
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# Now, resume the execution and make sure that GDB does not stop when
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# task 4 hits the breakpoint. Continuing thus results in our program
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# running to completion.
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gdb_continue_to_end "" continue 1
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