Commit 10b8e306 authored Aug 08, 2009 by Frederic Weisbecker Committed by Ingo Molnar Aug 09, 2009

perf_counter: Work around gcc warning by initializing tracepoint record unconditionally



Despite that the tracepoint record is always present when the
PERF_SAMPLE_TP_RECORD flag is set, gcc raises a warning,
thinking it might not be initialized:

  kernel/perf_counter.c: In function ‘perf_counter_output’:
  kernel/perf_counter.c:2650: warning: ‘tp’ may be used uninitialized in this function

Then, initialize it to NULL and always check if it's not NULL
before dereference it.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1249698400-5441-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 25446036

kernel/perf_counter.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -2646,7 +2646,7 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
		u64 counter;
		} group_entry;
		struct perf_callchain_entry *callchain = NULL;
		struct perf_tracepoint_record *tp;
		struct perf_tracepoint_record *tp = NULL;
		int callchain_size = 0;
		u64 time;
		struct {
		@@ -2717,6 +2717,7 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,

		if (sample_type & PERF_SAMPLE_TP_RECORD) {
		tp = data->private;
		if (tp)
		header.size += tp->size;
		}

		@@ -2783,7 +2784,7 @@ static void perf_counter_output(struct perf_counter *counter, int nmi,
		}
		}

		if (sample_type & PERF_SAMPLE_TP_RECORD)
		if ((sample_type & PERF_SAMPLE_TP_RECORD) && tp)
		perf_output_copy(&handle, tp->record, tp->size);

		perf_output_end(&handle);