From 53cccef118b80913d76c0737108f6c32471cd09e Mon Sep 17 00:00:00 2001 From: Tankut Baris Aktemur Date: Wed, 1 Apr 2020 21:33:06 +0200 Subject: gdb/infrun: stop all threads if there exists a non-stop target Stop all threads not only if the current target is non-stop, but also if there exists a non-stop target. The multi-target patch (5b6d1e4fa4f "Multi-target support") made the following change to gdb/inf-child.c: void inf_child_target::maybe_unpush_target () { - if (!inf_child_explicitly_opened && !have_inferiors ()) + if (!inf_child_explicitly_opened) unpush_target (this); } If we are in all-stop mode with multiple inferiors, and an exit event is received from an inferior, target_mourn_inferior() gets to this point and without the have_inferiors() check, the target is unpushed. This leads to having exec_ops as the top target. Here is a test scenario. Two executables, ./a.out returns immediately; ./sleepy just sleeps. $ gdb ./sleepy (gdb) start ... (gdb) add-inferior -exec ./a.out ... (gdb) inferior 2 [Switching to inferior 2.. (gdb) start ... (gdb) set schedule-multiple on (gdb) set debug infrun 1 (gdb) continue At this point, the exit event is received from ./a.out. Normally, this would lead to stop_all_threads() to also stop ./sleepy, but this doesn't happen, because target_is_non_stop_p() returns false. And it returns false because the top target is no longer the process target; it is the exec_ops. This patch modifies 'stop_waiting' to call 'stop_all_threads' if there exists a non-stop target, not just when the current top target is non-stop. Tested on X86_64 Linux. gdb/ChangeLog: 2020-04-01 Tankut Baris Aktemur * infrun.c (stop_all_threads): Update assertion, plus when stopping threads, take into account that we might be trying to stop an all-stop target. (stop_waiting): Call 'stop_all_threads' if there exists a non-stop target. gdb/testsuite/ChangeLog: 2020-04-01 Tankut Baris Aktemur * gdb.multi/stop-all-on-exit.c: New test. * gdb.multi/stop-all-on-exit.exp: New file. --- gdb/infrun.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'gdb/infrun.c') diff --git a/gdb/infrun.c b/gdb/infrun.c index 1fb445a..8ff34c3 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -4711,7 +4711,7 @@ stop_all_threads (void) int pass; int iterations = 0; - gdb_assert (target_is_non_stop_p ()); + gdb_assert (exists_non_stop_target ()); if (debug_infrun) fprintf_unfiltered (gdb_stdlog, "infrun: stop_all_threads\n"); @@ -4742,6 +4742,17 @@ stop_all_threads (void) to tell the target to stop. */ for (thread_info *t : all_non_exited_threads ()) { + /* For a single-target setting with an all-stop target, + we would not even arrive here. For a multi-target + setting, until GDB is able to handle a mixture of + all-stop and non-stop targets, simply skip all-stop + targets' threads. This should be fine due to the + protection of 'check_multi_target_resumption'. */ + + switch_to_thread_no_regs (t); + if (!target_is_non_stop_p ()) + continue; + if (t->executing) { /* If already stopping, don't request a stop again. @@ -4753,7 +4764,6 @@ stop_all_threads (void) "infrun: %s executing, " "need stop\n", target_pid_to_str (t->ptid).c_str ()); - switch_to_thread_no_regs (t); target_stop (t->ptid); t->stop_requested = 1; } @@ -7894,9 +7904,9 @@ stop_waiting (struct execution_control_state *ecs) /* Let callers know we don't want to wait for the inferior anymore. */ ecs->wait_some_more = 0; - /* If all-stop, but the target is always in non-stop mode, stop all + /* If all-stop, but there exists a non-stop target, stop all threads now that we're presenting the stop to the user. */ - if (!non_stop && target_is_non_stop_p ()) + if (!non_stop && exists_non_stop_target ()) stop_all_threads (); } -- cgit v1.1