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[2620:137:e000::1:9]) by mx.google.com with ESMTPS id w4si9606440ejz.118.2019.05.28.17.23.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 May 2019 17:23:30 -0700 (PDT) Received-SPF: neutral (google.com: 2620:137:e000::1:9 is neither permitted nor denied by best guess record for domain of davem@davemloft.net) client-ip=2620:137:e000::1:9; Authentication-Results: mx.google.com; spf=neutral (google.com: 2620:137:e000::1:9 is neither permitted nor denied by best guess record for domain of davem@davemloft.net) smtp.mailfrom=davem@davemloft.net Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::3d8]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 3319E1400E0D1; Tue, 28 May 2019 17:23:28 -0700 (PDT) Date: Tue, 28 May 2019 17:23:27 -0700 (PDT) Message-Id: <20190528.172327.2113097810388476996.davem@davemloft.net> To: rick.p.edgecombe@intel.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, luto@kernel.org, dave.hansen@intel.com, namit@vmware.com Subject: Re: [PATCH v5 0/2] Fix issues with vmalloc flush flag From: David Miller In-Reply-To: <20190527211058.2729-1-rick.p.edgecombe@intel.com> References: <20190527211058.2729-1-rick.p.edgecombe@intel.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 28 May 2019 17:23:28 -0700 (PDT) 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: From: Rick Edgecombe Date: Mon, 27 May 2019 14:10:56 -0700 > These two patches address issues with the recently added > VM_FLUSH_RESET_PERMS vmalloc flag. > > Patch 1 addresses an issue that could cause a crash after other > architectures besides x86 rely on this path. > > Patch 2 addresses an issue where in a rare case strange arguments > could be provided to flush_tlb_kernel_range(). It just occurred to me another situation that would cause trouble on sparc64, and that's if someone the address range of the main kernel image ended up being passed to flush_tlb_kernel_range(). That would flush the locked kernel mapping and crash the kernel instantly in a completely non-recoverable way.