[PATCH 2/4] perf symbols: Check if a struct machine instance was found

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Which can happen when processing old files that had no fake kernel MMAP,
events.

That shouldn't result in perf_session__create_kernel_maps not being
called, this will be fixed in a followup patch, for now do these checks
to avoid segfaulting.

Cc: FrÃdÃric Weisbecker <fweisbec@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Tom Zanussi <tzanussi@xxxxxxxxx>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/event.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 46563e1..c44a5a8 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -493,8 +493,10 @@ int event__process_mmap(event_t *self, struct perf_session *session)
 		return 0;
 	}
 
-	thread = perf_session__findnew(session, self->mmap.pid);
 	machine = perf_session__find_host_machine(session);
+	if (machine == NULL)
+		goto out_problem;
+	thread = perf_session__findnew(session, self->mmap.pid);
 	map = map__new(&machine->user_dsos, self->mmap.start,
 			self->mmap.len, self->mmap.pgoff,
 			self->mmap.pid, self->mmap.filename,
@@ -552,18 +554,12 @@ void thread__find_addr_map(struct thread *self,
 	if (cpumode == PERF_RECORD_MISC_KERNEL && perf_host) {
 		al->level = 'k';
 		machine = perf_session__find_host_machine(session);
-		mg = &machine->kmaps;
 	} else if (cpumode == PERF_RECORD_MISC_USER && perf_host) {
 		al->level = '.';
 		machine = perf_session__find_host_machine(session);
 	} else if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) {
 		al->level = 'g';
 		machine = perf_session__find_machine(session, pid);
-		if (!machine) {
-			al->map = NULL;
-			return;
-		}
-		mg = &machine->kmaps;
 	} else {
 		/*
 		 * 'u' means guest os user space.
@@ -586,6 +582,13 @@ void thread__find_addr_map(struct thread *self,
 
 		return;
 	}
+
+	if (machine == NULL) {
+		al->map = NULL;
+		return;
+	}
+
+	mg = &machine->kmaps;
 try_again:
 	al->map = map_groups__find(mg, type, al->addr);
 	if (al->map == NULL) {
-- 
1.6.2.5

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