From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00758C43381 for ; Thu, 21 Mar 2019 10:46:19 +0000 (UTC) Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B43ED218FD for ; Thu, 21 Mar 2019 10:46:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YOJDUuB0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B43ED218FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=kernelnewbies-bounces@kernelnewbies.org Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.91) (envelope-from ) id 1h6vCh-0000H0-N5; Thu, 21 Mar 2019 06:45:43 -0400 Received: from mail-wm1-x344.google.com ([2a00:1450:4864:20::344]) by shelob.surriel.com with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.91) (envelope-from ) id 1h6vCf-0000Gm-9q for kernelnewbies@kernelnewbies.org; Thu, 21 Mar 2019 06:45:41 -0400 Received: by mail-wm1-x344.google.com with SMTP id z6so1767622wmi.0 for ; Thu, 21 Mar 2019 03:45:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=6qhaFJn4BDljxmQmctEoR3rzRNYSKZLOBeZB5yLikTo=; b=YOJDUuB0zg+/F5Ni0Dkb+r1/aBby++gf9NG/dY4/nUf2Q3SN57F81/VMAlM4lfKn/Q MaU6myXmubKg5yjieQHkULPfWCKe3fxXGaohMDjdjF6lv+nIx6KnxL2N7vtEEFR1w/ee K/x/HbvseOV9zsxXWAu3jubd+hHOG1eUU2S1+qIM94H0olWeQPQLX//c8X/Bsl8tyyyG vDgvyUUR8O0Z1ROp4lbESae+F4EbUGAnLOKGTsFAwtGU+yil+8j2Z4kxpyOnIUsYb1Hp NKJknNvhy1h8n6HW8FPuZBWZoQUAqX2swd6U3qALz3WvUvAzZc1EwLWVm4oh6FuScgJp IFAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=6qhaFJn4BDljxmQmctEoR3rzRNYSKZLOBeZB5yLikTo=; b=EOmQuSfE2jg2/RFpEGEDwpD/fhb7liuANZI394V0FBTSz+QORPNysLWNSvqGaD7h7t IUTlN84lqv/PNnkepGrVJIKjjRk1hGdCgtyt09CGI3DYfhb39SlYUh71Y1iJOl4iw27y 35D3O/sa3nN0kW6iBCVwGxvaYj7q+X9giWF5fzJconl9EbECqB/lqd9tNcDj7KsW3yRz 8wrMQXUXjRu6K0CcKxkCtMVUYBcAHFB3/S60MJxzRvo8cs3Wa9vE0tleaERPj84dGVvR N887iQ1Lw6hB6HXlHH/x4DM/TvUp0hV19B2xoSOYAkUtmVfm8zEF9VHLK1KwSeAm7vOE PczQ== X-Gm-Message-State: APjAAAUVsEBSergQ1E8QZy5FUxIfL+K0vb48dBOcIYsFyGWSGFrim5K1 LtR6MUw/n524PHBVKMmn76w= X-Google-Smtp-Source: APXvYqwl61YaH3OSfPlm9RTE4r4HGxDNavYRIeSR+eKyjtQxgQvszQhUbdKzLcZCj2UkXf92IFbWOQ== X-Received: by 2002:a1c:c4cd:: with SMTP id u196mr1955438wmf.70.1553165137522; Thu, 21 Mar 2019 03:45:37 -0700 (PDT) Received: from narunkot ([94.11.212.65]) by smtp.gmail.com with ESMTPSA id 26sm6234659wmg.42.2019.03.21.03.45.36 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Thu, 21 Mar 2019 03:45:36 -0700 (PDT) Date: Thu, 21 Mar 2019 10:45:28 +0000 From: Okash Khawaja To: Lev Olshvang Subject: Re: What will happen if 2 processes map same physical page Message-ID: <20190321104528.33471e38@narunkot> In-Reply-To: <3935481553162177@sas2-ce04c18c415c.qloud-c.yandex.net> References: <6967041553089359@myt2-66bcb87429e6.qloud-c.yandex.net> <16760.1553101675@turing-police> <3935481553162177@sas2-ce04c18c415c.qloud-c.yandex.net> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Cc: linux-il , Valdis =?utf-8?Q?Kl=C4=93tnieks?= , kernelnewbies X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: kernelnewbies-bounces@kernelnewbies.org T24gVGh1LCAyMSBNYXIgMjAxOSAxMjo1NjoxNyArMDMwMApMZXYgT2xzaHZhbmcgPGxldm9uc2hl QHlhbmRleC5jb20+IHdyb3RlOgoKPiBIaSBWYWFsZGlzLAo+IAo+IFRoYW5rcyBmb3IgYW5zd2Vy LAo+IEkgc3RpbGwgd29uZGVyaW5nIHdoZXRoZXIgdGhlIGtlcm5lbCB3aWxsIGFsbG93IHdyaXRl IHRvIGEgcmVhZC1vbmx5Cj4gcGFnZSBvZiBzaGFyZWQgbGlicmFyeSB3aGlsZSBpdCBoYXMgbWFw cGVkIHRvIHNldmVyYWwgcHJvY2Vzc2VzPwo+IEtlcm5lbCBrbm93cyB0aGF0IHBhZ2UncyByZWZl cmVuY2UgY291bnQgPjEsICB3aWxsIGl0IGFsbG93Cj4gbW1hcC9tcHJvdGVjdCB0byBjaGFuZ2Ug cGFnZSBwcm90ZWN0aW9uID8gT3Igd2lsbCBpdCBhbGxvdyBkaXJlY3QKPiByaWdodCBieSBwaHlz aWNhbCBhZGRyZXNzPyBJIHN1cHBvc2UgdGhhdCBDUFUgc2hvdWxkIHJhaXNlIHBhZ2UgZmF1bHQK PiB3aGVuIHdyaXRlIGlzIG1hZGUgdG8gcmVhZCBvbmx5IHBhZ2UsIAo+IAo+IFdoYXQgaXMgdGhl IHNlcXVlbmNlICBDUFUgcmFpc2VzIHBhZ2UgZmF1bCBiZWZvcmUgd3JpdGUgdG8gcGFnZSBvZgo+ IGFmdGVyIGRhdGEgaXMgd3JpdHRlbiBXaWxsICBDUFUgd2FpdCB1bnRpbCBrZXJuZWwgd2lsbCBj b25zaWRlciB3aGF0Cj4gdG8gZG8gLCB3aGV0aGVyIGFncmVlIGFuZCBjaGFuZ2UgUFRFICAid3Jp dGFibGUgIiBiaXQgdG8gMSA/IE9yCj4ga2VybmVsIG1heSBkaXNhZ3JlZSBhbmQgcmFpc2UgU0VH RkFVTFQ/CgpOb3RlIHRoYXQgZWFjaCBwcm9jZXNzIGhhcyBpdHMgb3duIFBURS4gU28gUFRFIGlu IG9uZSBwcm9jZXNzIG1heSBzYXkKdGhlIHBhZ2UgaXMgd3JpdGFibGUgYW5kIFBURSBpbiBhbm90 aGVyIHByb2Nlc3MgbWF5IHNheSBpdCdzIHJlYWQtb25seS4KCj4gCj4gSSBjaGVja2VkIGluIHRo ZSBoYW5kbGVfbW1fZmF1bHQoKSAgY2FsbHMgZm9yCj4gYXJjaF92bWFfYWNjZXNzX3Blcm1pdHRl ZCgpIHdoaWNoIGp1c3QgcmV0dXJucyB0cnVlIG9uIG1vc3QKPiBhcmNoaXRlY3R1cmVzIHdoaWNo IGlzIHZlcnkgc3RyYW5nZSBhbmQgIGNvbnRyYWRpY3RzIG15IHByZWRpY3Rpb24gb2YKPiBTRUZG QVVMVC4gYXJjaF92bWFfYWNjZXNzX3Blcm1pdHRlZCgpIHJldHV0dXMgdHJ1ZSB3aGVuIGlzIHNl ZXMgdGhhdAo+IGFjY2VzcyBpcyBtYWRlIGZyb20gZm9yZWlnbiBwcm9jZXNzPwo+IGh0dHBzOi8v ZWxpeGlyLmJvb3RsaW4uY29tL2xpbnV4L2xhdGVzdC9pZGVudC9hcmNoX3ZtYV9hY2Nlc3NfcGVy bWl0dGVkCj4gCj4gSSBhbSB0b3RhbGx5IGNvbmZ1c2VkLgo+IAo+IFdoYXQgZG8geW91IHRoaW5r ID8KPiAKPiBSZWdhcmRzLAo+IExldgoKSXQgbG9va3MgbGlrZSB0aGVyZSBhcmUgdHdvIHNlcGFy YXRlIHF1ZXN0aW9ucyBpbiB0aGUgZW1haWwuCgoxKSBXaWxsIGtlcm5lbCBhbGxvdyB0aGUgc2Ft ZSBwaHlzaWNhbCBwYWdlIHRvIGJlIG1hcHBlZCBhcyByZWFkLW9ubHkKaW4gb25lIHByb2Nlc3Mg YW5kIGFzIHJlYWQtd3JpdGUgaW4gYW5vdGhlciBwcm9jZXNzPwoKMikgSG93IHBhZ2UgZmF1bHQg aXMgZ2VuZXJhdGVkPwoKQW5zd2VyIGZvciBmaXJzdCBpcyB5ZXMuIFNhbWUgcGh5c2ljYWwgcGFn ZSBjYW4gYmUgbWFwcGVkIHdpdGgKZGlmZmVyZW50IHBlcm1pc3Npb25zIGluIHR3byBkaWZmZXJl bnQgcHJvY2Vzc2VzLiBJdCBtZWFucyByZWFkLW9ubHkKcHJvY2VzcyB3aWxsIHVsdGltYXRlbHkg KGhvcGVmdWxseSB2ZXJ5IHNvb24pIG5vdGljZSBjaGFuZ2VzIG1hZGUgYnkKcmVhZC13cml0ZSBw cm9jZXNzLgoKQW5zd2VyIGZvciBzZWNvbmQgcXVlc3Rpb24gaXMgYSBiaXQgY29tcGxpY2F0ZWQu IEhvd2V2ZXIgdGhlcmUgaXMgYQp0cmljayB0byBpdC4gT25jZSB3ZSBrbm93IHRoYXQsIHJlc3Qg d2lsbCBiZWNvbWUgY2xlYXIgYXV0b21hdGljYWx5LgpUaGUgdHJpY2sgKGF0IGxlYXN0IGZvciB4 ODYgc3lzdGVtcykgaXMgdGhhdCBwZXJtaXNzaW9ucyBhcmUgbWFpbnRhaW5lZAphdCB0d28gZGlm ZmVyZW50IGxldmVsczoKCi0gVk1BIGxldmVsCi0gUFRFIGxldmVsIChvciBQVUQgbGV2ZWwgZm9y IGxhcmdlciBwYWdlIHNpemUgYnV0IHRoYXQgaXMgbm90IHJlbGV2YW50CiAgaGVyZSkKCldoZW4g YSBwYWdlIGluIG1lbW9yeSBpcyBhY2Nlc3NlZCwgcGVybWlzc2lvbiBvbiBjb3JyZXNwb25kaW5n IFZNQSBpcwpjaGVja2VkIGZpcnN0LiBJZiB0aGUgYWNjZXNzIGlzIGFsbG93ZWQgYnkgVk1BIHRo ZW4gUFRFIHBlcm1pc3Npb25zIGFyZQpjaGVja2VkLiBPdGhlcndpc2Ugc2VnZmF1bHQgaXMgZ2Vu ZXJhdGVkLiBJZiBwZXJtaXNzaW9ucyBhdCBQVEUgbGV2ZWwKZG9uJ3QgbWF0Y2ggdGhlIGFjY2Vz cyB0eXBlIHRoZW4gYSBwYWdlIGZhdWx0IGlzIGdlbmVyYXRlZC4gVGhhdCdzIHdoZW4KcGFnZSBm YXVsdCBoYW5kZXIga2lja3MgaW4gYW5kIHRyaWVzIHRvIHJlc29sdmUgdGhlIHByb2JsZW0gYnkg ZmF1bHRpbmcKdGhlIHBhZ2UgaW50byBSQU0sIGNvcHlpbmcgdGhlIHBhZ2UgaW4gUkFNIChmb3Ig Y29weS1vbi13cml0ZSkgZXRjLgoKPiAKPiAKPiAKPiAyMC4wMy4yMDE5LCAyMDowOCwgIlZhbGRp cyBLbMSTdG5pZWtzIiA8dmFsZGlzLmtsZXRuaWVrc0B2dC5lZHU+Ogo+ID4gT24gV2VkLCAyMCBN YXIgMjAxOSAxNjo0MjozOSArMDMwMCwgTGV2IE9sc2h2YW5nIHNhaWQ6ICAKPiA+PiDCoFRoZSBx dWVzdGlvbiBpcyBpdCBpcG9zc2libGxlIGluIExpbnV4L01NVS9UTEIgdGhhdCAyIHByb2Nlc3Nl cwo+ID4+IG1hcCB0byB0aGUgc2FtZSBwaHlzaWNhbCBhZGRyZXNzPyAgCj4gPgo+ID4gVG90YWxs eSBwb3NzaWJsZS4gVGhhdCdzIGhvdyBtbWFwIHNoYXJlZCBtZW1vcnkgd29ya3MsIGFuZCB3aHkK PiA+IHNoYXJlZCBsaWJyYXJpZXMgYXJlIHBvc3NpYmxlLgo+ID4gIAo+ID4+IMKgV2lsbCBDUFUg b3IgVExCIGRpc2NvdmVyIHRoYXQgc2Vjb25kIHByb2Nlc3MgdHJpZXMgdG8gcmVhY2gKPiA+PiBv Y2N1cGllZCBwaHlzaWNhbCBwYWdlPyAgCj4gPgo+ID4gV2VsbCwgdGhlIGhhcmR3YXJlIHdvbid0 IGRpc2NvdmVyIGl0IGFzIGEgInNlY29uZCIgcHJvY2VzcywgaXQgb25seQo+ID4ga25vd3MgaXQn cyBwcm9jZXNzaW5nICp0aGlzKiBtZW1vcnkgYWNjZXNzLgo+ID4gIAo+ID4+IMKgV2hhdCBpZiBm aXJzdCBwcm9jZXNzIHNldCBwYWdlIHBlcm1pc3Npb24gdG8gcmVhZCBhbmQgc2Vjb25kCj4gPj4g d2hhdHMgdG8gd3JpdGUgdG8gdGhpcyBwYWdlID8gIAo+ID4KPiA+IFBlcmZlY3RseSBPSyAtIHRo ZSB0d28gcHJvY2Vzc2VzIGhhdmUgc2VwYXJhdGUgcGFnZSB0YWJsZSBtYXBwaW5ncywKPiA+IHdp dGggc2VwYXJhdGUgcGVybWlzc2lvbiBiaXRzLiBTbyAoZm9yIGV4YW1wbGUpIHBoeXNpY2FsIHBh Z2UKPiA+IDB4MTdGMDAwIGlzIG1hcHBlZCB0byB2aXJ0dWFsIGFkZHJlc3MgMHgyMDM0RDAwMCB3 aXRoIHJlYWQtb25seQo+ID4gcGVybWlzc2lvbiBuIHByb2Nlc3MgMSdzIHBhZ2UgdGFibGVzLCBh bmQgdG8gdmlydHVhbCBhZGRyZXNzCj4gPiAweDk4RkYzMDAwIHdpdGggcmVhZC13cml0ZSBwZXJt aXNzaW9uIGluIHByb2Nlc3MgMidzIHBhZ2UgdGFibGVzLgo+ID4gTm8gcHJvYmxlbS4KPiA+Cj4g PiAoQW5kIGJlZm9yZSB5b3UgYXNrLCB5ZXMgaXQncyBwb3NzaWJsZSBmb3IgcHJvY2VzcyAyIHRv IHJ1bm5pbmcgb24KPiA+IG9uZSBjb3JlIGRvaW5nIGEgd3JpdGUgdG8gdGhlIHBhZ2UgYXQgdGhl IGV4YWN0IHNhbWUgdGltZSB0aGF0Cj4gPiBwcm9jZXNzIDEgaXMgZG9pbmcgYSByZWFkIG9uIGFu b3RoZXIgY29yZS4gRGVwZW5kaW5nIG9uIHRoZQo+ID4gaGFyZHdhcmUgY2FjaGUgZGVzaWduLCB0 aGlzIG1heSBvciBtYXkgbm90IGdldCBwcm9jZXNzIDEgdXBkYXRlZAo+ID4gZGF0YS4gVGhpcyBp cyB3aHkgbG9ja2luZyBhbmQgbWVtb3J5IGJhcnJpZXJzIGFyZSBpbXBvcnRhbnQuIFNlZQo+ID4g RG9jdW1lbnRhdGlvbi9tZW1vcnktYmFycmllcnMudHh0IGZvciBtb3JlIGRldGFpbHMpCj4gPgo+ ID4gIkFuZCB0aGVuIHRoZXJlJ3MgdGhlIEFscGhhIiAtIGEgcHJvY2Vzc29yIGRlc2lnbiB0aGF0 IGdvdCBtdWNoIG9mCj4gPiBpdHMgc3BlZWQgYnkgYmVpbmcgd2VpcmQgYWJvdXQgdGhpcyBzdHVm Zi4gOikKPiA+ICAKPiA+PiDCoFBlcmhhcHMgZHVyaW5nIGNvbnRleHQgc3dpdGNoIGFsbCBwYWdl IGFjY2VzcyBwZXJtaXNzaW9ucyBvZgo+ID4+IGZpcnN0IHByb2Nlc3MgaXMgZmxhc2hlZCBvdXQg ZnJvbSBNTVUgPyAgCj4gPgo+ID4gQWN0dWFsbHksIHRoZSBrZXJuZWwganVzdCBwb2ludHMgdGhl IE1NVSBhdCBhIG5ldyBzZXQgb2YgcGFnZSB0YWJsZQo+ID4gZW50cmllcyBhbmQgbGV0cyB0aGUg VExCIHJlbG9hZCBhcyBuZWVkZWQuIEluIHBhcnRpY3VsYXIsIG9uIG1vc3QKPiA+IGFyY2hpdGVj dHVyZXMsIHRoZSBrZXJuZWwgdHJpZXMgcmVhbGx5IGhhcmQgdG8gZW5zdXJlIHRoYXQgYWxsCj4g PiBwcm9jZXNzZXMgc2hhcmUgYXQgbGVhc3QgcGFydCBvZiB0aGVpciBwYWdlIHRhYmxlIG1hcHBp bmdzIHNvIHRoZQo+ID4ga2VybmVsIGlzIGFsd2F5cyBtYXBwZWQgYXQgdGhlIHNhbWUgcGxhY2Us IG1lYW5pbmcgdGhhdCB0aGVyZSdzIGEKPiA+IGJldHRlciBjaGFuY2UgdGhhdCBvbiBhIHN5c2Nh bGwsIHRoZSBUTEIgYWxyZWFkeSBoYXMgaG90IGVudHJpZXMKPiA+IGZvciBsYXJnZSBwYXJ0cyBv ZiB0aGUga2VybmVsIHNvIG5vIFRMQiByZWxvYWRzIGFyZSBuZWVkZWQuICAKPiAKPiBfX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwo+IEtlcm5lbG5ld2JpZXMg bWFpbGluZyBsaXN0Cj4gS2VybmVsbmV3Ymllc0BrZXJuZWxuZXdiaWVzLm9yZwo+IGh0dHBzOi8v bGlzdHMua2VybmVsbmV3Ymllcy5vcmcvbWFpbG1hbi9saXN0aW5mby9rZXJuZWxuZXdiaWVzCgoK X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KS2VybmVsbmV3 YmllcyBtYWlsaW5nIGxpc3QKS2VybmVsbmV3Ymllc0BrZXJuZWxuZXdiaWVzLm9yZwpodHRwczov L2xpc3RzLmtlcm5lbG5ld2JpZXMub3JnL21haWxtYW4vbGlzdGluZm8va2VybmVsbmV3Ymllcwo=