Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Ingo Molnar:
 "Tooling fixes: a 'perf record' deadlock fix plus debuggability fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf top: Show backtrace when handling a SIGSEGV on --stdio mode
  perf tools: Fix buildid processing
  perf tools: Make fork event processing more resilient
  perf tools: Avoid deadlock when map_groups are broken

4 files changed, 37 insertions, 4 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index de165a1b9240..20b56eb987f8 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -521,6 +521,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
                 goto out_child;
         }
 
+        /*
+         * Normally perf_session__new would do this, but it doesn't have the
+         * evlist.
+         */
+        if (rec->tool.ordered_events && !perf_evlist__sample_id_all(rec->evlist)) {
+                pr_warning("WARNING: No sample_id_all support, falling back to unordered processing\n");
+                rec->tool.ordered_events = false;
+        }
+
         if (!rec->evlist->nr_groups)
                 perf_header__clear_feat(&session->header, HEADER_GROUP_DESC);
 
@@ -965,9 +974,11 @@ static struct record record = {
         .tool = {
                 .sample         = process_sample_event,
                 .fork           = perf_event__process_fork,
+                .exit           = perf_event__process_exit,
                 .comm           = perf_event__process_comm,
                 .mmap           = perf_event__process_mmap,
                 .mmap2          = perf_event__process_mmap2,
+                .ordered_events = true,
         },
 };
 
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index ecf319728f25..6135cc07213c 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -601,8 +601,8 @@ static void display_sig(int sig __maybe_unused)
 
 static void display_setup_sig(void)
 {
-        signal(SIGSEGV, display_sig);
-        signal(SIGFPE,  display_sig);
+        signal(SIGSEGV, sighandler_dump_stack);
+        signal(SIGFPE, sighandler_dump_stack);
         signal(SIGINT,  display_sig);
         signal(SIGQUIT, display_sig);
         signal(SIGTERM, display_sig);
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 7ff682770fdb..f1a4c833121e 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1387,6 +1387,24 @@ int machine__process_fork_event(struct machine *machine, union perf_event *event
                                                         event->fork.ptid);
         int err = 0;
 
+        if (dump_trace)
+                perf_event__fprintf_task(event, stdout);
+
+        /*
+         * There may be an existing thread that is not actually the parent,
+         * either because we are processing events out of order, or because the
+         * (fork) event that would have removed the thread was lost. Assume the
+         * latter case and continue on as best we can.
+         */
+        if (parent->pid_ != (pid_t)event->fork.ppid) {
+                dump_printf("removing erroneous parent thread %d/%d\n",
+                            parent->pid_, parent->tid);
+                machine__remove_thread(machine, parent);
+                thread__put(parent);
+                parent = machine__findnew_thread(machine, event->fork.ppid,
+                                                 event->fork.ptid);
+        }
+
         /* if a thread currently exists for the thread id remove it */
         if (thread != NULL) {
                 machine__remove_thread(machine, thread);
@@ -1395,8 +1413,6 @@ int machine__process_fork_event(struct machine *machine, union perf_event *event
 
         thread = machine__findnew_thread(machine, event->fork.pid,
                                          event->fork.tid);
-        if (dump_trace)
-                perf_event__fprintf_task(event, stdout);
 
         if (thread == NULL || parent == NULL ||
             thread__fork(thread, parent, sample->time) < 0) {
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 28c4b746baa1..0a9ae8014729 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -191,6 +191,12 @@ static int thread__clone_map_groups(struct thread *thread,
         if (thread->pid_ == parent->pid_)
                 return 0;
 
+        if (thread->mg == parent->mg) {
+                pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
+                         thread->pid_, thread->tid, parent->pid_, parent->tid);
+                return 0;
+        }
+
         /* But this one is new process, copy maps. */
         for (i = 0; i < MAP__NR_TYPES; ++i)
                 if (map_groups__clone(thread->mg, parent->mg, i) < 0)