Messages in this thread Patch in this message | | | Date | Mon, 17 Mar 2014 16:12:01 -0400 | From | Tejun Heo <> | Subject | [PATCH percpu/for-3.15] percpu: allocation size should be even |
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From 2f69fa829cb4ca062aaffee9ab9eb44484db75b1 Mon Sep 17 00:00:00 2001 From: Viro <viro@ZenIV.linux.org.uk> Date: Mon, 17 Mar 2014 16:01:27 -0400
723ad1d90b56 ("percpu: store offsets instead of lengths in ->map[]") updated percpu area allocator to use the lowest bit, instead of sign, to signify whether the area is occupied and forced min align to 2; unfortunately, it forgot to force the allocation size to be even causing malfunctions for the very rare odd-sized allocations.
Always force the allocations to be even sized.
tj: Wrote patch description.
Original-patch-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Tejun Heo <tj@kernel.org> --- Applied to percpu/for-3.15.
Thanks.
mm/percpu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/percpu.c b/mm/percpu.c index c7206d0..202e104 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -713,11 +713,14 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) /* * We want the lowest bit of offset available for in-use/free - * indicator. + * indicator, so force >= 16bit alignment and make size even. */ if (unlikely(align < 2)) align = 2; + if (unlikely(size & 1)) + size++; + if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { WARN(true, "illegal size (%zu) or align (%zu) for " "percpu allocation\n", size, align); -- 1.8.5.3
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