On Sat, 16 Apr 2022 09:21:45 +0800 Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote: > > 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@xxxxxxxxxx> > >>> 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@xxxxxxxxxx> > >>> Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> > >>> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > >> > >> Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx> > >> > >> ... 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 > Does the v4 patch address the issues which were raised in this thread? --- a/mm/hugetlb.c~hugetlb-fix-wrong-use-of-nr_online_nodes-v4 +++ a/mm/hugetlb.c @@ -2986,8 +2986,6 @@ int __alloc_bootmem_huge_page(struct hst struct huge_bootmem_page *m = NULL; /* initialize for clang */ int nr_nodes, node; - if (nid != NUMA_NO_NODE && !node_online(nid)) - return 0; /* do node specific alloc */ if (nid != NUMA_NO_NODE) { m = memblock_alloc_try_nid_raw(huge_page_size(h), huge_page_size(h), @@ -4174,7 +4172,7 @@ static int __init hugepages_setup(char * pr_warn("HugeTLB: architecture can't support node specific alloc, ignoring!\n"); return 0; } - if (!node_online(tmp)) + if (tmp >= MAX_NUMNODES || !node_online(tmp)) goto invalid; node = array_index_nospec(tmp, MAX_NUMNODES); p += count + 1; _