From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id 1FCE46B0333 for ; Fri, 24 Mar 2017 02:03:01 -0400 (EDT) Received: by mail-pg0-f72.google.com with SMTP id 79so11081147pgf.2 for ; Thu, 23 Mar 2017 23:03:01 -0700 (PDT) Received: from out0-136.mail.aliyun.com (out0-136.mail.aliyun.com. [140.205.0.136]) by mx.google.com with ESMTP id v5si940213pfv.325.2017.03.23.23.02.59 for ; Thu, 23 Mar 2017 23:03:00 -0700 (PDT) Reply-To: "Hillf Danton" From: "Hillf Danton" References: <1490328162-21245-1-git-send-email-mike.kravetz@oracle.com> In-Reply-To: <1490328162-21245-1-git-send-email-mike.kravetz@oracle.com> Subject: Re: [PATCH] mm/hugetlb: Don't call region_abort if region_chg fails Date: Fri, 24 Mar 2017 14:02:55 +0800 Message-ID: <00da01d2a464$488ab360$d9a01a20$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: 'Mike Kravetz' , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: 'Dmitry Vyukov' , 'Michal Hocko' , "'Kirill A . Shutemov'" , 'Andrey Ryabinin' , 'Naoya Horiguchi' , 'Andrew Morton' On March 24, 2017 12:03 PM Mike Kravetz wrote: > > Changes to hugetlbfs reservation maps is a two step process. The first > step is a call to region_chg to determine what needs to be changed, and > prepare that change. This should be followed by a call to call to > region_add to commit the change, or region_abort to abort the change. > > The error path in hugetlb_reserve_pages called region_abort after a > failed call to region_chg. As a result, the adds_in_progress counter > in the reservation map is off by 1. This is caught by a VM_BUG_ON > in resv_map_release when the reservation map is freed. > > syzkaller fuzzer found this bug, that resulted in the following: > > kernel BUG at mm/hugetlb.c:742! > Call Trace: > hugetlbfs_evict_inode+0x7b/0xa0 fs/hugetlbfs/inode.c:493 > evict+0x481/0x920 fs/inode.c:553 > iput_final fs/inode.c:1515 [inline] > iput+0x62b/0xa20 fs/inode.c:1542 > hugetlb_file_setup+0x593/0x9f0 fs/hugetlbfs/inode.c:1306 > newseg+0x422/0xd30 ipc/shm.c:575 > ipcget_new ipc/util.c:285 [inline] > ipcget+0x21e/0x580 ipc/util.c:639 > SYSC_shmget ipc/shm.c:673 [inline] > SyS_shmget+0x158/0x230 ipc/shm.c:657 > entry_SYSCALL_64_fastpath+0x1f/0xc2 > RIP: resv_map_release+0x265/0x330 mm/hugetlb.c:742 > > Reported-by: Dmitry Vyukov > Signed-off-by: Mike Kravetz > --- Acked-by: Hillf Danton > mm/hugetlb.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index c7025c1..c65d45c 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -4233,7 +4233,9 @@ int hugetlb_reserve_pages(struct inode *inode, > return 0; > out_err: > if (!vma || vma->vm_flags & VM_MAYSHARE) > - region_abort(resv_map, from, to); > + /* Don't call region_abort if region_chg failed */ > + if (chg >= 0) > + region_abort(resv_map, from, to); > if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) > kref_put(&resv_map->refs, resv_map_release); > return ret; > -- > 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org