Messages in this thread | | | Date | Tue, 12 Feb 2019 14:07:56 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] perf/core: don't WARN for impossible rb sizes |
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On Tue, Feb 12, 2019 at 10:42:38AM +0800, Jin, Yao wrote: > > diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c > > index 4a9937076331..309ef5a64af5 100644 > > --- a/kernel/events/ring_buffer.c > > +++ b/kernel/events/ring_buffer.c > > @@ -734,6 +734,9 @@ 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) > > + goto fail; > > + > > rb = kzalloc(size, GFP_KERNEL);
Yes, Boris also send the entire morning bisecting this.
The problem is that @size is in bytes and MAX_ORDER is in pages.
That should be:
if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
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