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30 Oct 2019 11:01:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,248,1569308400"; d="scan'208";a="203955609" Received: from ray.jf.intel.com (HELO [10.7.201.139]) ([10.7.201.139]) by orsmga006.jf.intel.com with ESMTP; 30 Oct 2019 11:01:53 -0700 Subject: Re: [PATCH RFC] mm: add MAP_EXCLUSIVE to create exclusive user mappings From: Dave Hansen To: "Edgecombe, Rick P" , "peterz@infradead.org" Cc: "adobriyan@gmail.com" , "linux-kernel@vger.kernel.org" , "rppt@kernel.org" , "rostedt@goodmis.org" , "jejb@linux.ibm.com" , "tglx@linutronix.de" , "linux-mm@kvack.org" , "dave.hansen@linux.intel.com" , "linux-api@vger.kernel.org" , "x86@kernel.org" , "akpm@linux-foundation.org" , "hpa@zytor.com" , "mingo@redhat.com" , "luto@kernel.org" , "kirill@shutemov.name" , "bp@alien8.de" , "rppt@linux.ibm.com" , "arnd@arndb.de" References: <1572171452-7958-1-git-send-email-rppt@kernel.org> <1572171452-7958-2-git-send-email-rppt@kernel.org> <20191028123124.ogkk5ogjlamvwc2s@box> <20191028130018.GA7192@rapoport-lnx> <20191028131623.zwuwguhm4v4s5imh@box> <20191028135521.GB4097@hirez.programming.kicks-ass.net> <0a35765f7412937c1775daa05177b20113760aee.camel@intel.com> <20191028210052.GM4643@worktop.programming.kicks-ass.net> <69c57f7fa9a1be145827673b37beff155a3adc3c.camel@intel.com> <20191030100418.GV4097@hirez.programming.kicks-ass.net> <775eb0cf-7189-a314-5dde-f720b56ec3b2@intel.com> Openpgp: preference=signencrypt Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <775eb0cf-7189-a314-5dde-f720b56ec3b2@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/30/19 10:58 AM, Dave Hansen wrote: > Modules also require privilege. IMNHO, if BPF is fracturing large swaths the direct map with no privilege, it's only a matter of time until it starts to cause problems. The fact that we do it today is only evidence that we have a ticking time bomb, not that it's OK.