From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 0BD136B0003 for ; Fri, 25 May 2018 16:16:49 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id b25-v6so3498817pfn.10 for ; Fri, 25 May 2018 13:16:49 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id x14-v6sor7025020pgq.277.2018.05.25.13.16.47 for (Google Transport Security); Fri, 25 May 2018 13:16:47 -0700 (PDT) Date: Fri, 25 May 2018 13:16:45 -0700 (PDT) From: David Rientjes Subject: [patch] mm, hugetlb_cgroup: suppress SIGBUS when hugetlb_cgroup charge fails Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Mike Kravetz , "Aneesh Kumar K.V" , Naoya Horiguchi , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org When charging to a hugetlb_cgroup fails, alloc_huge_page() returns ERR_PTR(-ENOSPC) which will cause VM_FAULT_SIGBUS to be returned to the page fault handler. Instead, return the proper error code, ERR_PTR(-ENOMEM), so VM_FAULT_OOM is handled correctly. This is consistent with failing mem cgroup charges in the non-hugetlb fault path. At the same time, restructure the return paths of alloc_huge_page() so it is consistent. Signed-off-by: David Rientjes --- mm/hugetlb.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2006,8 +2006,10 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, * code of zero indicates a reservation exists (no change). */ map_chg = gbl_chg = vma_needs_reservation(h, vma, addr); - if (map_chg < 0) - return ERR_PTR(-ENOMEM); + if (map_chg < 0) { + ret = -ENOMEM; + goto out; + } /* * Processes that did not create the mapping will have no @@ -2019,8 +2021,8 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, if (map_chg || avoid_reserve) { gbl_chg = hugepage_subpool_get_pages(spool, 1); if (gbl_chg < 0) { - vma_end_reservation(h, vma, addr); - return ERR_PTR(-ENOSPC); + ret = -ENOSPC; + goto out_reservation; } /* @@ -2049,8 +2051,10 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, if (!page) { spin_unlock(&hugetlb_lock); page = alloc_buddy_huge_page_with_mpol(h, vma, addr); - if (!page) + if (!page) { + ret = -ENOSPC; goto out_uncharge_cgroup; + } if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { SetPagePrivate(page); h->resv_huge_pages--; @@ -2087,8 +2091,10 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, out_subpool_put: if (map_chg || avoid_reserve) hugepage_subpool_put_pages(spool, 1); +out_reservation: vma_end_reservation(h, vma, addr); - return ERR_PTR(-ENOSPC); +out: + return ERR_PTR(ret); } int alloc_bootmem_huge_page(struct hstate *h)