diff options
| author | Ingo Molnar <mingo@kernel.org> | 2012-12-08 15:42:17 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-12-08 15:42:47 +0100 |
| commit | 08cd2a6960ae2e1aa7f44b44ebafa84f503a2dd1 (patch) | |
| tree | b8a4f41686c3478f3b938155c866730164b8906c | |
| parent | fd6da696f38b00ffeae1185d6f0ec5d4ab3b472d (diff) | |
| parent | 9366c1ba13fbc41bdb57702e75ca4382f209c82f (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.c | 2 | ||||
| -rw-r--r-- | kernel/trace/ring_buffer.c | 16 |
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) { iter->pos = 0; iter->func_pos = 0; - iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH); + iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH); } static 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) struct list_head *head_page_with_bit; head_page = &rb_set_head_page(cpu_buffer)->list; + if (!head_page) + break; prev_page = head_page->prev; first_page = pages->next; @@ -2934,7 +2936,7 @@ unsigned long ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu) unsigned long flags; struct ring_buffer_per_cpu *cpu_buffer; struct buffer_page *bpage; - unsigned long ret; + unsigned long ret = 0; if (!cpumask_test_cpu(cpu, buffer->cpumask)) return 0; @@ -2949,7 +2951,8 @@ unsigned long ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu) bpage = cpu_buffer->reader_page; else bpage = rb_set_head_page(cpu_buffer); - ret = bpage->page->time_stamp; + if (bpage) + ret = bpage->page->time_stamp; raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); return ret; @@ -3260,6 +3263,8 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) * Splice the empty reader page into the list around the head. */ reader = rb_set_head_page(cpu_buffer); + if (!reader) + goto out; cpu_buffer->reader_page->list.next = rb_list_head(reader->list.next); cpu_buffer->reader_page->list.prev = reader->list.prev; @@ -3778,12 +3783,17 @@ void ring_buffer_read_finish(struct ring_buffer_iter *iter) { struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer; + unsigned long flags; /* * Ring buffer is disabled from recording, here's a good place - * to check the integrity of the ring buffer. + * to check the integrity of the ring buffer. + * Must prevent readers from trying to read, as the check + * clears the HEAD page and readers require it. */ + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); rb_check_pages(cpu_buffer); + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); atomic_dec(&cpu_buffer->record_disabled); atomic_dec(&cpu_buffer->buffer->resize_disabled); |