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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 3D229C43603 for ; Wed, 18 Dec 2019 10:02:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E929B2072B for ; Wed, 18 Dec 2019 10:02:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qK/w+MUQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E929B2072B Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 747B18E0103; Wed, 18 Dec 2019 05:02:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6D1B28E00F5; Wed, 18 Dec 2019 05:02:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5990B8E0103; Wed, 18 Dec 2019 05:02:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0057.hostedemail.com [216.40.44.57]) by kanga.kvack.org (Postfix) with ESMTP id 409EB8E00F5 for ; Wed, 18 Dec 2019 05:02:15 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id EF96A3A9E for ; Wed, 18 Dec 2019 10:02:14 +0000 (UTC) X-FDA: 76277821788.24.truck38_30a8fe4765120 X-HE-Tag: truck38_30a8fe4765120 X-Filterd-Recvd-Size: 5949 Received: from mail-wm1-f65.google.com (mail-wm1-f65.google.com [209.85.128.65]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Wed, 18 Dec 2019 10:02:14 +0000 (UTC) Received: by mail-wm1-f65.google.com with SMTP id u2so1176786wmc.3 for ; Wed, 18 Dec 2019 02:02:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Fj+2DIyRgCK5xuABekjKl+39Q2AHZPtEEm4P6By4ZjI=; b=qK/w+MUQFZ9Bql2lg9A0KrLekjdU4if2axm/7GcHDfOa10hfHYtVjWwSE4kuhkD8SR 08oy5rDE8BEl5uUkDoLQuQlkzD7lMz9YV6lkOVh4ScKkGh1MHLLY6MANGEiMiKEux1TH N3v7hVzSIj4MiHVWsNx5cRo/nHtvZN1V5++LOrKnA656TKkDa+oTESd0WCxPrxvBRTiK u9xEvcu7fvsR1TDHu82R9TdM2Ntmrc2kTzMMIMT/cEzEfzkLOJ4n5clIeYLg7fPBClec 6O31gTnaNjnVotf1dt/C8JVgYMzEXZFDNbBcxjIVOnpQ10fAHtosdK8PbMt9o6KP3GZ7 Du6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Fj+2DIyRgCK5xuABekjKl+39Q2AHZPtEEm4P6By4ZjI=; b=SIoA9r3bgEXVvVqzDIuNjW5b9TDJKW5qjZ3m70xVttI8I/HnrEDnzQekGVT7/zAq40 ucwtOabEuBORS9QfXvI/n8JfMklGr2jqvWZ/jIoDIier+8pllPqNGAKkzedoqB8lSEbz p9OGX4dHerxQZ3BrDMNjhngLd0JTxjEBSsR434FNY4N7pEN4AH1ou7hd1gE7QAJOXgYH NeAaMxKbIlACAoo5K5XZxsjy1TWMKt1I3UuLNfA61rT6oK5TzI+rZigOty/gWJ3JA8Su VRHnhUckXUzqfgco1PP1rNzVPGzPKctEfpqRK7kUrk8rid9ImMXi1m8r4+QbfZz91c3s mMZA== X-Gm-Message-State: APjAAAV/c6/jdSaVtsJ8+kCKSn1pfJ5Tv8n78MY3tqYWeZjqlc9GszE0 WUjNLHa9IkLJVjW8HUsWwlzbAP+uznBTe+aZHoqyPg== X-Google-Smtp-Source: APXvYqwNmBpNMdHWReX/D5c68xpRw2T0uGUahy0C843WzEjKT5VQGe0PqAMyROWsbJHphaLLgyn0K+hghM0ZsL5jvnQ= X-Received: by 2002:a7b:cf01:: with SMTP id l1mr2142402wmg.86.1576663332648; Wed, 18 Dec 2019 02:02:12 -0800 (PST) MIME-Version: 1.0 References: <20191122112621.204798-1-glider@google.com> <20191122112621.204798-25-glider@google.com> In-Reply-To: From: Alexander Potapenko Date: Wed, 18 Dec 2019 11:02:01 +0100 Message-ID: Subject: Re: [PATCH RFC v3 24/36] kmsan: disable instrumentation of certain functions To: Andrey Konovalov Cc: Thomas Gleixner , Andrew Morton , Vegard Nossum , Dmitry Vyukov , Linux Memory Management List , Alexander Viro , Andreas Dilger , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , Christoph Hellwig , "Darrick J. Wong" , "David S. Miller" , Dmitry Torokhov , Eric Biggers , Eric Dumazet , Eric Van Hensbergen , Greg Kroah-Hartman , Harry Wentland , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Marek Szyprowski , Marco Elver , Mark Rutland , "Martin K. Petersen" , Martin Schwidefsky , Matthew Wilcox , "Michael S . Tsirkin" , Michal Simek , Petr Mladek , Qian Cai , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , "Theodore Ts'o" , Vasily Gorbik , Wolfram Sang Content-Type: text/plain; charset="UTF-8" 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: > The comment style around __no_sanitize_memory looks very different for > different call sites, perhaps it makes sense to unify it somehow. Done in v4. > > +/* > > + * Dark magic happening here, let's not instrument this function. > > + * Also avoid copying any metadata by using raw __memmove(). > > + */ > > +__no_sanitize_memory > > struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) > > { > > /* > > @@ -648,10 +656,10 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) > > (struct bad_iret_stack *)this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1; > > > > /* Copy the IRET target to the new stack. */ > > - memmove(&new_stack->regs.ip, (void *)s->regs.sp, 5*8); > > + __memmove(&new_stack->regs.ip, (void *)s->regs.sp, 5*8); > > > > /* Copy the remainder of the stack from the current stack. */ > > - memmove(new_stack, s, offsetof(struct bad_iret_stack, regs.ip)); > > + __memmove(new_stack, s, offsetof(struct bad_iret_stack, regs.ip)); > > Looks like this change should go into a separate patch. I disagree. Both the __no_sanitize_memory annotation and __memmove() calls serve the same purpose: avoid calling KMSAN code from fixup_bad_iret(). I don't think it makes sense to separate them. > > + kmsan_unpoison_shadow(args, sizeof(*args)); > > + regs = args->regs; > > + if (regs) > > + kmsan_unpoison_shadow(regs, sizeof(*regs)); > > This one as well. Done in v4.