From: Miaohe Lin <linmiaohe@xxxxxxxxxx> Subject: mm/hugeltb: handle the error case in hugetlb_fix_reserve_counts() A rare out of memory error would prevent removal of the reserve map region for a page. hugetlb_fix_reserve_counts() handles this rare case to avoid dangling with incorrect counts. Unfortunately, hugepage_subpool_get_pages and hugetlb_acct_memory could possibly fail too. We should correctly handle these cases. Link: https://lkml.kernel.org/r/20210410072348.20437-5-linmiaohe@xxxxxxxxxx Fixes: b5cec28d36f5 ("hugetlbfs: truncate_hugepages() takes a range of pages") Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx> Cc: Feilong Lin <linfeilong@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/hugetlb.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/mm/hugetlb.c~mm-hugeltb-handle-the-error-case-in-hugetlb_fix_reserve_counts +++ a/mm/hugetlb.c @@ -742,13 +742,20 @@ void hugetlb_fix_reserve_counts(struct i { struct hugepage_subpool *spool = subpool_inode(inode); long rsv_adjust; + bool reserved = false; rsv_adjust = hugepage_subpool_get_pages(spool, 1); - if (rsv_adjust) { + if (rsv_adjust > 0) { struct hstate *h = hstate_inode(inode); - hugetlb_acct_memory(h, 1); + if (!hugetlb_acct_memory(h, 1)) + reserved = true; + } else if (!rsv_adjust) { + reserved = true; } + + if (!reserved) + pr_warn("hugetlb: Huge Page Reserved count may go negative.\n"); } /* _
