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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2C42C27C79 for ; Thu, 20 Jun 2024 14:19:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 337596B049F; Thu, 20 Jun 2024 10:19:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 30DCD6B04A0; Thu, 20 Jun 2024 10:19:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1AEA36B04A1; Thu, 20 Jun 2024 10:19:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id F2B916B049F for ; Thu, 20 Jun 2024 10:19:44 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 9562C401F8 for ; Thu, 20 Jun 2024 14:19:44 +0000 (UTC) X-FDA: 82251475488.17.5B36F5D Received: from mail-ot1-f46.google.com (mail-ot1-f46.google.com [209.85.210.46]) by imf07.hostedemail.com (Postfix) with ESMTP id C1C994001E for ; Thu, 20 Jun 2024 14:19:42 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b="w+m/nSB4"; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf07.hostedemail.com: domain of glider@google.com designates 209.85.210.46 as permitted sender) smtp.mailfrom=glider@google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1718893175; a=rsa-sha256; cv=none; b=l19u5mM1hX0Qq8L1gZa0AaR9v/ge7LF0HaoELY3uqwe/utq2ODKv1bDAb1tabRB1u9Vv05 pq4BPXDKyg/PW3mS+OubeOuKIvWWzNlUlCvvUSP6rBEzftHOjD73xNuf9SqWTLB3HhGB+j MI5lLZ9rFmLzsMWbADDWPcVvgAF74OA= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b="w+m/nSB4"; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf07.hostedemail.com: domain of glider@google.com designates 209.85.210.46 as permitted sender) smtp.mailfrom=glider@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1718893175; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=bv+xOEqws+KjvoyS4k7q1BnMnYne+DLlcGkvkV1YXWI=; b=4b+QefJPyb6VlwCdJhCIuh/6EqkVCzCiexR/mZjnB0c50gZruRc/F1YJ03aEyZr+eKXB2X br2wuaPg9CEoBHZi35TvQFgGogYi2vHnkev0whjTdFPdzM77Ph+6mwUZvwdR8NOyu/DtVe SOdDa5jAScC/b7AKhPgvr6kM01lksO4= Received: by mail-ot1-f46.google.com with SMTP id 46e09a7af769-700986e3092so145295a34.2 for ; Thu, 20 Jun 2024 07:19:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1718893182; x=1719497982; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=bv+xOEqws+KjvoyS4k7q1BnMnYne+DLlcGkvkV1YXWI=; b=w+m/nSB4GH5M90R9twHZQULHA65GnThtu/Q6+J3mj9q7WraGxnDE8s2AeaOuixtj4Y /nnHBAOjBEinFKZF6WT1QU+/JGWSNh7zWoCSaF+GJKB3oKRrSfw4rOAVUY8CYgf9Pa4x qBazkwGGaA9DILI7QnqBBsUV13RC+e5YhWNmPoQM8+bBSDnFP88tEIiS8n0iikbZ6wRk 70VtfzC9V30RdmkhRXokQgYBDQjU3Ui9R4ZmRQZuoNZy/VrQ4ob9ZYOwDhwaRkCUAtrM 3OqhqMHEyBTrC9UW3XEh34Nt+jnf051dJpOm5PQc0iz+RlM/No2OuHIfy1n0/PnqnNeM GIRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718893182; x=1719497982; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=bv+xOEqws+KjvoyS4k7q1BnMnYne+DLlcGkvkV1YXWI=; b=MTVE99ylNDaUg+SKsGlox1vcceRrZDMG1EDcX2W35n+SoJjhDBrycB4TnTeo3ZsHaL vU2nOEeXWzkaRjNYlF+vhhrAQ4Rpu6bOf5YTocbKCuoNPH+8UQzBd2rM6NKXAoRldhJR 8ddrHjjlDZo2EJZmlQAeLBhQnudpwnzuVd/rquvfN06AHyP0EtjiBJVDwz/pCEhed0Wl 2Um7kX+QvLjQ0UBz1bo+lTPxyASMcALPfpV+Er0EoVtgyM4OhtGVkOnb+b9E3xdnj95v yuLKPqPQkgKohsYuKvRu5GQnW5tdnaEqodih9KPtPn7M3JFzYFVrmuPfFQFUMulS/Dl0 G/DA== X-Forwarded-Encrypted: i=1; AJvYcCX6bdV31ED2oC5U7MlCqD6ZFuRNZ1uh1+xhmregLnXwojP5V3FAiMJjGJJllSDQHg6ocDLJ5xoRDMpW6W8riDU/jd4= X-Gm-Message-State: AOJu0Yzhgh65yOBoincPe1oJCWCxvx4Q2QDkQtTeN6TNuJAcLJDNraJ+ 8fu60RtafHZ4AO1NtAWP+CRMMj7zqf05LU6k1BuZVR7EbF41LgfTFQYBv6z69EWSGZBZFhjqugl x3TTbLh++fTJxMBnrgbvzV3/nL4mKkxwRzyud X-Google-Smtp-Source: AGHT+IE09fsEZr9ZoSHdbUKHBdTeeBAjnGuixlRzRpM0AHsB+sO1SZNTjr1raJ9+9DFih0kA9gjaCoNKe5irm0Thh/4= X-Received: by 2002:a9d:5f14:0:b0:6fd:591d:9e21 with SMTP id 46e09a7af769-700771e7dc8mr6110157a34.33.1718893181456; Thu, 20 Jun 2024 07:19:41 -0700 (PDT) MIME-Version: 1.0 References: <20240619154530.163232-1-iii@linux.ibm.com> <20240619154530.163232-37-iii@linux.ibm.com> In-Reply-To: From: Alexander Potapenko Date: Thu, 20 Jun 2024 16:19:04 +0200 Message-ID: Subject: Re: [PATCH v5 36/37] s390/kmsan: Implement the architecture-specific functions To: Ilya Leoshkevich Cc: Alexander Gordeev , Andrew Morton , Christoph Lameter , David Rientjes , Heiko Carstens , Joonsoo Kim , Marco Elver , Masami Hiramatsu , Pekka Enberg , Steven Rostedt , Vasily Gorbik , Vlastimil Babka , Christian Borntraeger , Dmitry Vyukov , Hyeonggon Yoo <42.hyeyoo@gmail.com>, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Mark Rutland , Roman Gushchin , Sven Schnelle Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: C1C994001E X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 57oso8ueif5uazq5i1mebnsjj8seqfic X-HE-Tag: 1718893182-25218 X-HE-Meta: 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 2VHoy1VE st36gocFWt/gTKIAlb2DmczvHWMluxp0mNRP/LPEdn7dEUQFdfAXY8risvcIJsxO2O4nA4mD4CbG6/0z9//0w14klnmnNGX8hnjsGyix/pz4ABXAMUx3+TATPvD447xNZaWFObRRJvYeSo2KUvbXzQ49y+JF0CSEUOoIpoAvnx+TUIqPPhj0j3GdKt62QoD8Y50iqunLwlXjcBj8kc333U6krFJqpVlptogowzR3ceM4EoasCh+JT9RL3vIYh80AaBQx6ZXwK3kQdAnckjerlfG5VHZEIZ5MYbf9wWrVFx3IrSp8qqQHotCCSmDicvQtkvu69y7+EKzQtHjUjjGVZauSLXpgYPt+2pneS X-Bogosity: Ham, tests=bogofilter, spamicity=0.000202, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jun 20, 2024 at 4:18=E2=80=AFPM Alexander Potapenko wrote: > > On Thu, Jun 20, 2024 at 3:38=E2=80=AFPM Ilya Leoshkevich wrote: > > > > On Thu, 2024-06-20 at 11:25 +0200, Alexander Gordeev wrote: > > > On Wed, Jun 19, 2024 at 05:44:11PM +0200, Ilya Leoshkevich wrote: > > > > > > Hi Ilya, > > > > > > > +static inline bool is_lowcore_addr(void *addr) > > > > +{ > > > > + return addr >=3D (void *)&S390_lowcore && > > > > + addr < (void *)(&S390_lowcore + 1); > > > > +} > > > > + > > > > +static inline void *arch_kmsan_get_meta_or_null(void *addr, bool > > > > is_origin) > > > > +{ > > > > + if (is_lowcore_addr(addr)) { > > > > + /* > > > > + * Different lowcores accessed via S390_lowcore > > > > are described > > > > + * by the same struct page. Resolve the prefix > > > > manually in > > > > + * order to get a distinct struct page. > > > > + */ > > > > > > > + addr +=3D (void > > > > *)lowcore_ptr[raw_smp_processor_id()] - > > > > + (void *)&S390_lowcore; > > > > > > If I am not mistaken neither raw_smp_processor_id() itself, nor > > > lowcore_ptr[raw_smp_processor_id()] are atomic. Should the preemption > > > be disabled while the addr is calculated? > > > > > > But then the question arises - how meaningful the returned value is? > > > AFAICT kmsan_get_metadata() is called from a preemptable context. > > > So if the CPU is changed - how useful the previous CPU lowcore meta > > > is? > > > > This code path will only be triggered by instrumented code that > > accesses lowcore. That code is supposed to disable preemption; > > if it didn't, it's a bug in that code and it should be fixed there. > > > > > > > > Is it a memory block that needs to be ignored instead? > > > > > > > + if (WARN_ON_ONCE(is_lowcore_addr(addr))) > > > > + return NULL; > > > > > > lowcore_ptr[] pointing into S390_lowcore is rather a bug. > > > > Right, but AFAIK BUG() calls are discouraged. I guess in a debug tool > > the rules are more relaxed, but we can recover from this condition here > > easily, that's why I still went for WARN_ON_ONCE(). > > We have KMSAN_WARN_ON() for that, sorry for not pointing it out > earlier: https://elixir.bootlin.com/linux/latest/source/mm/kmsan/kmsan.h#= L46 Apart from that: Reviewed-by: Alexander Potapenko