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[2001:8b0:10b:1231::1]) by mx.google.com with ESMTPS id j123si857693itj.70.2019.03.02.10.46.03 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sat, 02 Mar 2019 10:46:03 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of peterz@infradead.org designates 2001:8b0:10b:1231::1 as permitted sender) client-ip=2001:8b0:10b:1231::1; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=merlin.20170209 header.b=CUzTz9l1; spf=pass (google.com: best guess record for domain of peterz@infradead.org designates 2001:8b0:10b:1231::1 as permitted sender) smtp.mailfrom=peterz@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=tx4ASGBAzLGHsjmHKiJQSkY9E3fWxtKwk1dKqdKBjR8=; b=CUzTz9l1sHNMNJg65FqQcW45S jQAFFCxjQF9ThgJz3A2Qvr2QT45McJuM8YIR0vQeFzNmS/wR11nfAumCVEAHUM4t3OsmTzkCqHF/P gtGPY1sPXpEnJQsu4XUwGvBLkiIQv1FN/rnY92a+uZywkBZ+82w0O+PE5gRmwxKLrIYMJP06yJGia +4CiKQjyBin8njbFCmMveZcadT33ew7N3UPuy7P0Qwd7SZJERQIo4DdMli0v+Jy+rEv0yrX4DkVOW E61kXZopbu9X7CIGf/f0f6RsC9sXhFhwVCjLMC5lIrITnNhlX0nwtgN5Fyvi2kUd52lbXvuSAzp/b njtINShxQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h09do-0001Yd-RN; Sat, 02 Mar 2019 18:45:45 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 5ED0E984351; Sat, 2 Mar 2019 19:45:44 +0100 (CET) Date: Sat, 2 Mar 2019 19:45:44 +0100 From: Peter Zijlstra To: Jan Stancek Cc: linux-mm@kvack.org, akpm@linux-foundation.org, willy@infradead.org, riel@surriel.com, mhocko@suse.com, ying.huang@intel.com, jrdr.linux@gmail.com, jglisse@redhat.com, aneesh.kumar@linux.ibm.com, david@redhat.com, aarcange@redhat.com, raquini@redhat.com, rientjes@google.com, kirill@shutemov.name, mgorman@techsingularity.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/memory.c: do_fault: avoid usage of stale vm_area_struct Message-ID: <20190302184544.GM14054@worktop.programming.kicks-ass.net> References: <20190302171043.GP11592@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Mar 02, 2019 at 07:19:39PM +0100, Jan Stancek wrote: > static vm_fault_t do_fault(struct vm_fault *vmf) > { > struct vm_area_struct *vma = vmf->vma; > + struct mm_struct *vm_mm = READ_ONCE(vma->vm_mm); Would this not need a corresponding WRITE_ONCE() in vma_init() ?