From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-x242.google.com (mail-pl0-x242.google.com [IPv6:2607:f8b0:400e:c01::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 409lHL3FXjzF29F for ; Wed, 28 Mar 2018 08:57:34 +1100 (AEDT) Received: by mail-pl0-x242.google.com with SMTP id u11-v6so277151plq.1 for ; Tue, 27 Mar 2018 14:57:34 -0700 (PDT) Date: Tue, 27 Mar 2018 14:57:31 -0700 (PDT) From: David Rientjes To: Laurent Dufour cc: paulmck@linux.vnet.ibm.com, peterz@infradead.org, Andrew Morton , kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , Andrea Arcangeli , Alexei Starovoitov , kemi.wang@intel.com, sergey.senozhatsky.work@gmail.com, Daniel Jordan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com, Tim Chen , linuxppc-dev@lists.ozlabs.org, x86@kernel.org Subject: Re: [PATCH v9 08/24] mm: Protect VMA modifications using VMA sequence count In-Reply-To: <1520963994-28477-9-git-send-email-ldufour@linux.vnet.ibm.com> Message-ID: References: <1520963994-28477-1-git-send-email-ldufour@linux.vnet.ibm.com> <1520963994-28477-9-git-send-email-ldufour@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 13 Mar 2018, Laurent Dufour wrote: > diff --git a/mm/mmap.c b/mm/mmap.c > index 5898255d0aeb..d6533cb85213 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -847,17 +847,18 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start, > } > > if (start != vma->vm_start) { > - vma->vm_start = start; > + WRITE_ONCE(vma->vm_start, start); > start_changed = true; > } > if (end != vma->vm_end) { > - vma->vm_end = end; > + WRITE_ONCE(vma->vm_end, end); > end_changed = true; > } > - vma->vm_pgoff = pgoff; > + WRITE_ONCE(vma->vm_pgoff, pgoff); > if (adjust_next) { > - next->vm_start += adjust_next << PAGE_SHIFT; > - next->vm_pgoff += adjust_next; > + WRITE_ONCE(next->vm_start, > + next->vm_start + (adjust_next << PAGE_SHIFT)); > + WRITE_ONCE(next->vm_pgoff, next->vm_pgoff + adjust_next); > } > > if (root) { > @@ -1781,6 +1782,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > out: > perf_event_mmap(vma); > > + vm_write_begin(vma); > vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); > if (vm_flags & VM_LOCKED) { > if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || > @@ -1803,6 +1805,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > vma->vm_flags |= VM_SOFTDIRTY; > > vma_set_page_prot(vma); > + vm_write_end(vma); > > return addr; > Shouldn't this also protect vma->vm_flags? diff --git a/mm/mmap.c b/mm/mmap.c --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1796,7 +1796,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma == get_gate_vma(current->mm))) mm->locked_vm += (len >> PAGE_SHIFT); else - vma->vm_flags &= VM_LOCKED_CLEAR_MASK; + WRITE_ONCE(vma->vm_flags, + vma->vm_flags & VM_LOCKED_CLEAR_MASK); } if (file) @@ -1809,7 +1810,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, * then new mapped in-place (which must be aimed as * a completely new data area). */ - vma->vm_flags |= VM_SOFTDIRTY; + WRITE_ONCE(vma->vm_flags, vma->vm_flags | VM_SOFTDIRTY); vma_set_page_prot(vma); vm_write_end(vma);