From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934287AbcHJU1W (ORCPT ); Wed, 10 Aug 2016 16:27:22 -0400 Received: from mail-db5eur01on0094.outbound.protection.outlook.com ([104.47.2.94]:23823 "EHLO EUR01-DB5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933568AbcHJU1S (ORCPT ); Wed, 10 Aug 2016 16:27:18 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=dsafonov@virtuozzo.com; Subject: Re: [PATCHv2 3/6] x86/arch_prctl/vdso: add ARCH_MAP_VDSO_* To: Andy Lutomirski References: <20160629105736.15017-1-dsafonov@virtuozzo.com> <20160629105736.15017-4-dsafonov@virtuozzo.com> <20160711182654.GA19160@redhat.com> <20160712141446.GB28837@redhat.com> CC: Oleg Nesterov , Michal Hocko , "Vladimir Davydov" , "linux-kernel@vger.kernel.org" , Dmitry Safonov <0x7f454c46@gmail.com>, "linux-mm@kvack.org" , Ingo Molnar , Cyrill Gorcunov , , Andy Lutomirski , Thomas Gleixner , "H. 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Currently we can't probe vdso page(s). >> >> >> So, to make sure, that I've understood correctly, I need to: >> o add vm_file to vdso/vvar vmas, __install_special_mapping will init >> them; >> o place array pages[] inside f_mapping; >> o create f_inode for each file -- for this we need some mount point, so >> I'll create something like vdsofs, register this filesystem and mount >> it in initcall (or like do_basic_setup - as it's done by shmem, i.e). >> >> Is this the idea, or I got it wrong? >> >> And maybe the idea is to create fake vm_file for just reference >> counting, but do not treat/init it like file with inode, etc? >> So with fake file I can also check if vdso is mapped already, but >> I'm sure the fake file will not help Oleg with uprobes. > > This would work, but it might be complicated. I'm not an expert at mm > internals. Ok, thanks on answer! I'll try to prepare patches in near days -- they will help to track vdso and for uprobes. If this will become too complex, I'll just iterate over vmas. > > Another approach would be to just iterate over all vmas and look for > old copies of the special mapping. Thanks, Dmitry