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authorIngo Molnar <mingo@kernel.org>2012-12-08 09:42:17 -0500
committerIngo Molnar <mingo@kernel.org>2012-12-08 09:42:47 -0500
commit08cd2a6960ae2e1aa7f44b44ebafa84f503a2dd1 (patch)
treeb8a4f41686c3478f3b938155c866730164b8906c
parentfd6da696f38b00ffeae1185d6f0ec5d4ab3b472d (diff)
parent9366c1ba13fbc41bdb57702e75ca4382f209c82f (diff)
Merge branch 'tip/perf/urgent-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/urgent
Pull ftrace fixes from Steve Rostedt. Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/trace/ftrace.c2
-rw-r--r--kernel/trace/ring_buffer.c16
2 files changed, 14 insertions, 4 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 9dcf15d38380..51b71594f321 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2437,7 +2437,7 @@ static void reset_iter_read(struct ftrace_iterator *iter)
2437{ 2437{
2438 iter->pos = 0; 2438 iter->pos = 0;
2439 iter->func_pos = 0; 2439 iter->func_pos = 0;
2440 iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH); 2440 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2441} 2441}
2442 2442
2443static void *t_start(struct seq_file *m, loff_t *pos) 2443static void *t_start(struct seq_file *m, loff_t *pos)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index b979426d16c6..4cb5e5147165 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1396,6 +1396,8 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer)
1396 struct list_head *head_page_with_bit; 1396 struct list_head *head_page_with_bit;
1397 1397
1398 head_page = &rb_set_head_page(cpu_buffer)->list; 1398 head_page = &rb_set_head_page(cpu_buffer)->list;
1399 if (!head_page)
1400 break;
1399 prev_page = head_page->prev; 1401 prev_page = head_page->prev;
1400 1402
1401 first_page = pages->next; 1403 first_page = pages->next;
@@ -2934,7 +2936,7 @@ unsigned long ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu)
2934 unsigned long flags; 2936 unsigned long flags;
2935 struct ring_buffer_per_cpu *cpu_buffer; 2937 struct ring_buffer_per_cpu *cpu_buffer;
2936 struct buffer_page *bpage; 2938 struct buffer_page *bpage;
2937 unsigned long ret; 2939 unsigned long ret = 0;
2938 2940
2939 if (!cpumask_test_cpu(cpu, buffer->cpumask)) 2941 if (!cpumask_test_cpu(cpu, buffer->cpumask))
2940 return 0; 2942 return 0;
@@ -2949,7 +2951,8 @@ unsigned long ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu)
2949 bpage = cpu_buffer->reader_page; 2951 bpage = cpu_buffer->reader_page;
2950 else 2952 else
2951 bpage = rb_set_head_page(cpu_buffer); 2953 bpage = rb_set_head_page(cpu_buffer);
2952 ret = bpage->page->time_stamp; 2954 if (bpage)
2955 ret = bpage->page->time_stamp;
2953 raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); 2956 raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
2954 2957
2955 return ret; 2958 return ret;
@@ -3260,6 +3263,8 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
3260 * Splice the empty reader page into the list around the head. 3263 * Splice the empty reader page into the list around the head.
3261 */ 3264 */
3262 reader = rb_set_head_page(cpu_buffer); 3265 reader = rb_set_head_page(cpu_buffer);
3266 if (!reader)
3267 goto out;
3263 cpu_buffer->reader_page->list.next = rb_list_head(reader->list.next); 3268 cpu_buffer->reader_page->list.next = rb_list_head(reader->list.next);
3264 cpu_buffer->reader_page->list.prev = reader->list.prev; 3269 cpu_buffer->reader_page->list.prev = reader->list.prev;
3265 3270
@@ -3778,12 +3783,17 @@ void
3778ring_buffer_read_finish(struct ring_buffer_iter *iter) 3783ring_buffer_read_finish(struct ring_buffer_iter *iter)
3779{ 3784{
3780 struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer; 3785 struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
3786 unsigned long flags;
3781 3787
3782 /* 3788 /*
3783 * Ring buffer is disabled from recording, here's a good place 3789 * Ring buffer is disabled from recording, here's a good place
3784 * to check the integrity of the ring buffer. 3790 * to check the integrity of the ring buffer.
3791 * Must prevent readers from trying to read, as the check
3792 * clears the HEAD page and readers require it.
3785 */ 3793 */
3794 raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
3786 rb_check_pages(cpu_buffer); 3795 rb_check_pages(cpu_buffer);
3796 raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
3787 3797
3788 atomic_dec(&cpu_buffer->record_disabled); 3798 atomic_dec(&cpu_buffer->record_disabled);
3789 atomic_dec(&cpu_buffer->buffer->resize_disabled); 3799 atomic_dec(&cpu_buffer->buffer->resize_disabled);