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Re: [PATCH with testcase] Bug 11568 - delete thread-specific breakpoint on the thread exit
- From: Yao Qi <yao at codesourcery dot com>
- To: Muhammad Waqas <mwaqas at codesourcery dot com>
- Cc: <gdb-patches at sourceware dot org>, <tromey at redhat dot com>, <ali_anwar at codesourcery dot com>
- Date: Wed, 31 Jul 2013 10:40:26 +0800
- Subject: Re: [PATCH with testcase] Bug 11568 - delete thread-specific breakpoint on the thread exit
- References: <51F619CE dot 5040407 at codesourcery dot com> <51F633E5 dot 7000302 at codesourcery dot com> <51F65519 dot 2080806 at codesourcery dot com> <51F67992 dot 30704 at codesourcery dot com> <51F7967E dot 3060900 at codesourcery dot com>
On 07/30/2013 06:33 PM, Muhammad Waqas wrote:
--- gdb/breakpoint.c 24 Jul 2013 19:50:32 -0000 1.773
+++ gdb/breakpoint.c 30 Jul 2013 10:20:49 -0000
@@ -11941,6 +11941,17 @@ breakpoint_auto_delete (bpstat bs)
{
if (b->disposition == disp_del_at_next_stop)
delete_breakpoint (b);
+ else if (b->thread > 0)
+ {
+ /* If breakpoint relates to user created thread Check if it's
+ not alive then delete it. */
+ struct thread_info *tp = find_thread_id (b->thread);
+
+ if ( tp != NULL && (tp->state == THREAD_EXITED
^ redundant space after parenthesis.
+ || !target_thread_alive (tp->ptid)))
+ delete_breakpoint(b);
+
+ }
}
}
Problem was with my test case, now It works with async/non-stop mode.
One more thing below...
+ # get the id of thread
+ set thre $expect_out(1,string)
+ gdb_breakpoint [gdb_get_line_number "line # 13"]
+ gdb_breakpoint "main thread $thre"
+ gdb_test "info break" ".*breakpoint.*(thread $thre)" "Breakpoint set"
+ gdb_test "thread $thre" "Switching to thread $thre.*" "Thread $thre selected"
+ gdb_continue_to_breakpoint "line # 13"
+ set test "thread-specific breakpoint is deleted"
+ gdb_test_multiple "info breakpoint" $test {
We continue to line 33, and type command 'info breakpoint' to check the
thread-specific breakpoint is disappeared. We take an assumption that
when main thread hits breakpoint on line 33, thread 2 has been exited,
and GDB has known about it. However, in async/non-stop mode, it is not
always true.
The exit of thread 2 happens before thread 1 hits breakpoint on line 33.
However, the order of 'thread 1 hits breakpoint' and 'GDB knows about
thread 2's exit' is not determined, in some runs (in async/non-stop
mode), I can get the fail below,
continue^M
Continuing.^M
^M
Breakpoint 3, main () at
../../../../git/gdb/testsuite/gdb.threads/thread-specific-bp.c:33^M
33 return 0; /*line # 13*/^M
(gdb) PASS: gdb.threads/thread-specific-bp.exp: continue to breakpoint:
line # 13
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
thread 1 hits breakpoint first,
[Thread 0xb7fddb40 (LWP 19876) exited]^M
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
GDB is aware of the exist of thread 2 then, so the thread-specific
breakpoint is not deleted.
info breakpoint^M
Num Type Disp Enb Address What^M
1 breakpoint keep y 0x08048487 in main at
../../../../git/gdb/testsuite/gdb.threads/thread-specific-bp.c:31^M
breakpoint already hit 1 time^M
2 breakpoint keep y 0x08048477 in start at
../../../../git/gdb/testsuite/gdb.threads/thread-specific-bp.c:24^M
breakpoint already hit 1 time^M
3 breakpoint keep y 0x080484bf in main at
../../../../git/gdb/testsuite/gdb.threads/thread-specific-bp.c:33^M
breakpoint already hit 1 time^M
4 breakpoint keep y 0x08048487 in main at
../../../../git/gdb/testsuite/gdb.threads/thread-specific-bp.c:31 thread 2^M
stop only in thread 2^M
(gdb) FAIL: gdb.threads/thread-specific-bp.exp: thread-specific
breakpoint is deleted
I suggest that we can add a breakpoint command 'info threads' in the
breakpoint, which forces GDB to update the list of threads, IMO. I add
this below in the test, and didn't see the fail after many runs of test.
gdb_breakpoint [gdb_get_line_number "line # 13"]
# Force GDB to update its knowledge on existing threads when this
# breakpoint is hit. Otherwise, GDB doesn't realize thread $thre
# has exited and doesn't remove the thread specific breakpoint.
gdb_test "commands\ninfo threads\nend" "End with.*" "add breakpoint
commands"
The patch looks in a good shape now. I don't have any comments. Leave
it to people who can approve it.
--
Yao (éå)