perf tools: Move dereference after NULL test

In each case, if the NULL test on thread is needed, then the
dereference should be after the NULL test.

A simplified version of the semantic match that detects this
problem is as follows (http://coccinelle.lip6.fr/):

// <smpl>
@match exists@
expression x, E;
identifier fld;
@@

* x->fld
  ... when != \(x = E\|&x\)
* x == NULL
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
LKML-Reference: <Pine.LNX.4.64.0910170842500.9213@ask.diku.dk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-annotate.c

@@ -104,14 +104,14 @@ process_sample_event(event_t *event, unsigned long offset, unsigned long head)
 		event->ip.pid,
 		(void *)(long)ip);
 
-	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
-
 	if (thread == NULL) {
 		fprintf(stderr, "problem processing %d event, skipping it.\n",
 			event->header.type);
 		return -1;
 	}
 
+	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
+
 	if (event->header.misc & PERF_RECORD_MISC_KERNEL) {
 		level = 'k';
 		sym = kernel_maps__find_symbol(ip, &map);

tools/perf/builtin-report.c

@@ -629,14 +629,14 @@ process_sample_event(event_t *event, unsigned long offset, unsigned long head)
 		}
 	}
 
-	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
-
 	if (thread == NULL) {
 		eprintf("problem processing %d event, skipping it.\n",
 			event->header.type);
 		return -1;
 	}
 
+	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
+
 	if (comm_list && !strlist__has_entry(comm_list, thread->comm))
 		return 0;
 

tools/perf/builtin-sched.c

@@ -1667,14 +1667,14 @@ process_sample_event(event_t *event, unsigned long offset, unsigned long head)
 		(void *)(long)ip,
 		(long long)period);
 
-	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
-
 	if (thread == NULL) {
 		eprintf("problem processing %d event, skipping it.\n",
 			event->header.type);
 		return -1;
 	}
 
+	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
+
 	if (profile_cpu != -1 && profile_cpu != (int) cpu)
 		return 0;
 

tools/perf/builtin-trace.c

@@ -80,14 +80,14 @@ process_sample_event(event_t *event, unsigned long offset, unsigned long head)
 		(void *)(long)ip,
 		(long long)period);
 
-	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
-
 	if (thread == NULL) {
 		eprintf("problem processing %d event, skipping it.\n",
 			event->header.type);
 		return -1;
 	}
 
+	dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
+
 	if (sample_type & PERF_SAMPLE_RAW) {
 		struct {
 			u32 size;