From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+iBZHr86AS0tHiRAbi444nu8UDUUk/bHCdrlzfBiu3B474Ozo0kiQFp3ooEXGYc+YF95Vb ARC-Seal: i=1; a=rsa-sha256; t=1523021635; cv=none; d=google.com; s=arc-20160816; b=w7pW3YfwAKt6RzRYYkJDhPMoBOHr+15y5tP7gQm0oD08kuZXc9m9BgMQuV6ZWfmYfb BTkiiFuSTQeBqyWutPK5Q7rd3aV/7+q7wiFiT8mc79mPLJB/v4WBFtADJKtKM5AAZNN6 4Am2SSqGH4XBh5mEKf7NHlLTL1yRlO0k60NgwRAwI5MVkDotKRStCc6EH0ZmWWO2WvHo FiL9ImwZ/OwINC+Mb3M6AgRJ8htQzWMVP1sN4xyunOIbGpbqyTvUG4EF0i/aySUyZqoj N1T2s1/ROJ0IfRp4kQBX4kOLUuKfoInl1Pz1oeEjf5xm2QOG3cvuxVN6uLvxLwI8fRcl kWxg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=4Up6+U2L55+/O5gs0KCgUOLBZ4vH3e2vJEg5zQPlxlo=; b=eVWGHHGwNsh5QufPw3Pwxz3HERGbAa4KA9jLPWTgy4HHzOy8yuJKuZN6ZLMJ2SwOM9 OI3IaTiX9vML/g7l06pjZONAAUplSMtDGR+kiFbu6YqkBUewjy2f6dtkRwstqcXJ6ke7 E1hggr3y6KEZUM3kqPXhhY0MQD9kaSH5TIAL/xX9t+3z+T3ijO19PQUd6WCF+2bbQcHf aabMAGED5hE4lZd5PhwLPYAzlqXHqAOWGH9KL7NhnstSBM+Z5TP0iZ9McyJzbeez4MsV T2GDFqpVZbRjrJvGhTl1PoROh2Mb2yrAV9dKp/ljUQw9D6DpiukBSSlPNb98iP3frKGD Q14w== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Kravetz , Laurent Dufour , Dan Williams , Michal Hocko , Davidlohr Bueso , Manfred Spraul , Andrew Morton , Linus Torvalds Subject: [PATCH 4.9 008/102] ipc/shm.c: add split function to shm_vm_ops Date: Fri, 6 Apr 2018 15:22:49 +0200 Message-Id: <20180406084332.690189179@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180406084331.507038179@linuxfoundation.org> References: <20180406084331.507038179@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597003934238227068?= X-GMAIL-MSGID: =?utf-8?q?1597003934238227068?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Kravetz commit 3d942ee079b917b24e2a0c5f18d35ac8ec9fee48 upstream. If System V shmget/shmat operations are used to create a hugetlbfs backed mapping, it is possible to munmap part of the mapping and split the underlying vma such that it is not huge page aligned. This will untimately result in the following BUG: kernel BUG at /build/linux-jWa1Fv/linux-4.15.0/mm/hugetlb.c:3310! Oops: Exception in kernel mode, sig: 5 [#1] LE SMP NR_CPUS=2048 NUMA PowerNV Modules linked in: kcm nfc af_alg caif_socket caif phonet fcrypt CPU: 18 PID: 43243 Comm: trinity-subchil Tainted: G C E 4.15.0-10-generic #11-Ubuntu NIP: c00000000036e764 LR: c00000000036ee48 CTR: 0000000000000009 REGS: c000003fbcdcf810 TRAP: 0700 Tainted: G C E (4.15.0-10-generic) MSR: 9000000000029033 CR: 24002222 XER: 20040000 CFAR: c00000000036ee44 SOFTE: 1 NIP __unmap_hugepage_range+0xa4/0x760 LR __unmap_hugepage_range_final+0x28/0x50 Call Trace: 0x7115e4e00000 (unreliable) __unmap_hugepage_range_final+0x28/0x50 unmap_single_vma+0x11c/0x190 unmap_vmas+0x94/0x140 exit_mmap+0x9c/0x1d0 mmput+0xa8/0x1d0 do_exit+0x360/0xc80 do_group_exit+0x60/0x100 SyS_exit_group+0x24/0x30 system_call+0x58/0x6c ---[ end trace ee88f958a1c62605 ]--- This bug was introduced by commit 31383c6865a5 ("mm, hugetlbfs: introduce ->split() to vm_operations_struct"). A split function was added to vm_operations_struct to determine if a mapping can be split. This was mostly for device-dax and hugetlbfs mappings which have specific alignment constraints. Mappings initiated via shmget/shmat have their original vm_ops overwritten with shm_vm_ops. shm_vm_ops functions will call back to the original vm_ops if needed. Add such a split function to shm_vm_ops. Link: http://lkml.kernel.org/r/20180321161314.7711-1-mike.kravetz@oracle.com Fixes: 31383c6865a5 ("mm, hugetlbfs: introduce ->split() to vm_operations_struct") Signed-off-by: Mike Kravetz Reported-by: Laurent Dufour Reviewed-by: Laurent Dufour Tested-by: Laurent Dufour Reviewed-by: Dan Williams Acked-by: Michal Hocko Cc: Davidlohr Bueso Cc: Manfred Spraul Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- ipc/shm.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/ipc/shm.c +++ b/ipc/shm.c @@ -381,6 +381,17 @@ static int shm_fault(struct vm_area_stru return sfd->vm_ops->fault(vma, vmf); } +static int shm_split(struct vm_area_struct *vma, unsigned long addr) +{ + struct file *file = vma->vm_file; + struct shm_file_data *sfd = shm_file_data(file); + + if (sfd->vm_ops && sfd->vm_ops->split) + return sfd->vm_ops->split(vma, addr); + + return 0; +} + #ifdef CONFIG_NUMA static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) { @@ -503,6 +514,7 @@ static const struct vm_operations_struct .open = shm_open, /* callback for a new vm-area open */ .close = shm_close, /* callback for when the vm-area is released */ .fault = shm_fault, + .split = shm_split, #if defined(CONFIG_NUMA) .set_policy = shm_set_policy, .get_policy = shm_get_policy,