Perf tool now is broken by commit 9dff0aa95a32 ("perf/core: Don't WARN()
for impossible ring-buffer sizes"). The get_order() should be used but not
the order_base_2(). This mistake makes mmap() on perf fd always fail.
Fixes: 9dff0aa95a32 ("perf/core: Don't WARN() for impossible ring-buffer sizes")
Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Julien Thierry <julien.thierry@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
kernel/events/ring_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 309ef5a64af5..55faafca4a6e 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -734,7 +734,7 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
size = sizeof(struct ring_buffer);
size += nr_pages * sizeof(void *);
- if (order_base_2(size) >= MAX_ORDER)
+ if (get_order(size) >= MAX_ORDER)
goto fail;
rb = kzalloc(size, GFP_KERNEL);
--
2.19.1
