Messages in this thread | | | Date | Sat, 16 Apr 2022 09:21:45 +0800 | Subject | Re: [PATCH v3 1/4] hugetlb: Fix wrong use of nr_online_nodes | From | Kefeng Wang <> |
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On 2022/4/15 13:41, Kefeng Wang wrote: > > On 2022/4/15 10:09, Davidlohr Bueso wrote: >> On Wed, 13 Apr 2022, Peng Liu wrote: >> >>> Certain systems are designed to have sparse/discontiguous nodes. In >>> this case, nr_online_nodes can not be used to walk through numa node. >>> Also, a valid node may be greater than nr_online_nodes. >>> >>> However, in hugetlb, it is assumed that nodes are contiguous. Recheck >>> all the places that use nr_online_nodes, and repair them one by one. >>> >>> Suggested-by: David Hildenbrand <david@redhat.com> >>> Fixes: 4178158ef8ca ("hugetlbfs: fix issue of preallocation of >>> gigantic pages can't work") >>> Fixes: b5389086ad7b ("hugetlbfs: extend the definition of hugepages >>> parameter to support node allocation") >>> Fixes: e79ce9832316 ("hugetlbfs: fix a truncation issue in hugepages >>> parameter") >>> Fixes: f9317f77a6e0 ("hugetlb: clean up potential spectre issue >>> warnings") >>> Signed-off-by: Peng Liu <liupeng256@huawei.com> >>> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> >>> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> >> >> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> >> >> ... but >> >>> --- >>> mm/hugetlb.c | 12 ++++++------ >>> 1 file changed, 6 insertions(+), 6 deletions(-) >>> >>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >>> index b34f50156f7e..5b5a2a5a742f 100644 >>> --- a/mm/hugetlb.c >>> +++ b/mm/hugetlb.c >>> @@ -2979,7 +2979,7 @@ int __alloc_bootmem_huge_page(struct hstate >>> *h, int nid) >>> struct huge_bootmem_page *m = NULL; /* initialize for clang */ >>> int nr_nodes, node; >>> >>> - if (nid != NUMA_NO_NODE && nid >= nr_online_nodes) >>> + if (nid != NUMA_NO_NODE && !node_online(nid)) >> >> afaict null_blk could also use this, actually the whole thing wants a >> helper - node_valid()? >> > This one should be unnecessary, and this patch looks has a bug, > > if a very nid passed to node_online(), it may crash, could you > re-check it, > > see my changes below, > > 1) add tmp check against MAX_NUMNODES before node_online() check, > > and move it after get tmp in hugepages_setup() , this could cover > both per-node alloc and normal alloc
sorry,for normal alloc, tmp is the number of huge pages, we don't need the movement, only add tmp >= MAX_NUMNODES is ok
> > 2) due to for_each_online_node() usage, we can drop additional check > of nid in __alloc_bootmem_huge_page() >
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