From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 35B58606A329 for ; Sun, 1 Nov 2026 20:02:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=WPNGg2UF Received: by kanga.kvack.org (Postfix) id 2243C6B05B2; Sun, 1 Nov 2026 15:02:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1FAB86B05B3; Sun, 1 Nov 2026 15:02:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 137C76B05B4; Sun, 1 Nov 2026 15:02:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id E4F846B05B2 for ; Sun, 1 Nov 2026 15:02:57 -0500 (EST) Received: from smtpin11.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 6DE88809E2 for ; Sun, 1 Nov 2026 20:02:55 +0000 (UTC) X-FDA: 85387623510.11.C8059FE Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf06.hostedemail.com (Postfix) with ESMTP id BF97018000B for ; Sun, 1 Nov 2026 20:02:53 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=WPNGg2UF; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793563373; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=0SOJOJhsdif+go/5LJX1b5wSejdt1NsbUiyp9y70uTo=; b=SlFHtCQPZCq9+ROdoJtUVFwEL2+fmoU6+MuUL9/ywiqqJzmIZ/vhLIwNQ0Ipfz6zbTgYbo JrtQYgbTJ3bLyCi79t+ogIhvgkp7yo5k+/KqqwpPY2SZ41CKBSV7mPOmROvir3tM3oZEJK HsUyJt0h0JM4XTBRsK6j0ntXsC0ObBc= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=WPNGg2UF; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793563373; b=bm8jenRDeXFx0CEUCF20GRGgjNVmHkPv/YIIaRbCHbLgG3mP3FZozZZF37+t5iwftuxUAM dlzmyxa9LKvQx7BZS5SYUIwo0FE2rRMjOHDgPT0C2E9bvz7aWAdNY8tG5CWbH/gPUGSy8s qmOS+9NAX3c3jY7tAOeIdxgsSJgKyFQ= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 0581543CE4; Sun, 1 Nov 2026 20:02:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BD5F1F00A1F; Sun, 1 Nov 2026 20:02:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793563372; bh=0SOJOJhsdif+go/5LJX1b5wSejdt1NsbUiyp9y70uTo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=WPNGg2UFCH8oHLxBKLsk+XSbOwxF9rgh4nqmQJ4tGq+b/EXkueNSv/mUnpHe3LXTa vVluDdes8rduQB1kHH0qnPxYIyTpIdeNMxc8d3/hE32sD/nAC42CBB2NZjzjwaoFKq VSfWDWS4ofbNNxRwkpWxOicfIWhXrFR5GTU++pvsJt1mFFhIjNQMHzbTibJdmUZwEl shnLe4dYc7bBcVf24pjhWeZ+yUtZLJ3rqG60ptgsmN8Uot0ZF7l/u6/9+ih0PTdWtU cK/6PBKoyC0PY6UDnhR/dmnnBtE45aSMdmbZobi90DRIuD7AmkyMtioQdRZsBRVIOO QgUz6fdgRIgag== Date: Sun, 1 Nov 2026 22:02:37 +0200 From: Mike Rapoport To: vrilutza@gmail.com Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Kees Cook , Borislav Petkov , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, Ilya Leoshkevich Subject: Re: [PATCH v2 3/4] mm: Factor __pfn_valid() out of pfn_valid() Message-ID: References: <20261101-kmsan-serie-v2-0-f97f66dc57ef@gmail.com> <20261101-kmsan-serie-v2-3-f97f66dc57ef@gmail.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261101-kmsan-serie-v2-3-f97f66dc57ef@gmail.com> X-Rspamd-Queue-Id: BF97018000B X-Stat-Signature: qpnzf7q5snw4jiesh7cdgbzt7xs56hmx X-Rspamd-Server: rspam06 X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793563373-493310 X-HE-Meta: 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 ZfKgHlAn bQfNCUAHUOXjmuZ4wHYLpefJaD+ld9A0Y89QH8rpkyv741h68mMHWCIxFvSy5f4sjLwylbHNkWEBAiGgfBPbWC+SlYt5lMMzd2nCZit1AB/c9eVIhI1FFa2chy6IXNXOS9vTPxSE6Hokdmk/Z+NUjH5x9n9krCC5dVHzENKQ5TdYOHVyuCfTMAPUDdVC0AoOVfP6NmLkg3I+/jbJbXUojxA6abn4kWAAbvBgNQyb60+YHbFhr4xW4tWWqoTFMT4VXE4c1PKpBgvX496wc3qYtGW1Mf3QIP59oqp1+SYogJ9X9m7Ed6AH7TdFC1bKG70Pls0TvBB82zJm8ow6VdH8dB9kSUMHg1VUByA8A26sgEA4jy1J98KvySkxmIw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Sun, Nov 01, 2026 at 07:04:38PM +0200, Viorel Cernateanu via B4 Relay wrote: > From: Viorel Cernateanu > > KMSAN needs to validate a PFN during metadata lookup without entering > instrumented code. Calling pfn_valid() also calls > rcu_read_lock_sched(), which can enter instrumented code and recurse > into the metadata lookup. > > Extract the PFN checks into __pfn_valid(), whose caller must already > be in an RCU-sched read-side critical section. Keep pfn_valid() as > the wrapper that acquires and releases that protection. > > This lets KMSAN reuse the existing PFN validation while providing > the required protection without instrumented helpers. > > The wrapper now also holds the RCU-sched read lock during the > initial range checks, which previously ran before acquiring it. > > Suggested-by: Alexander Potapenko > Signed-off-by: Viorel Cernateanu Acked-by: Mike Rapoport (Microsoft) > --- > include/linux/mmzone.h | 42 +++++++++++++++++++++++++----------------- > 1 file changed, 25 insertions(+), 17 deletions(-) -- Sincerely yours, Mike.