Hi Peter, Ingo and Arnaldo, Could you help review this and have this fix merged in next RC? The perf is totaly broken now! Thanks.
On Tue, Feb 12, 2019 at 11:52:21PM +0800, Changbin Du wrote:
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@gmail.com Cc: Mark Rutland mark.rutland@arm.com Cc: Julien Thierry julien.thierry@arm.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Jiri Olsa jolsa@redhat.com Cc: Peter Zijlstra peterz@infradead.org Cc: Ingo Molnar mingo@redhat.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: stable@vger.kernel.org
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