From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E2BC837F306; Fri, 4 Sep 2026 06:01:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501702; cv=none; b=oaBvc1+XuE1c+tw62sCOoChF6B/jhQuKMqCGFDMQyhOhWtk3Z2eLhYJKNZZKpxEmTv1LU9i/1YFY3tqZxo8F68Ma6jPUkTJesz6lAgr97iS+2QWcHrphJYTJBg3KbN4kEd4ouuAoiA/csyvCXUOBywVEiBJRYhQwAyyjlJLcRew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501702; c=relaxed/simple; bh=mqE2nGr70+Qh7r4WlveZb4NRuAysh91wtIr6090TGFg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Yz+xiMMcZa1iA6iIvWxglns3+69+CvNMp+9YpJ36eXDDOG6odDtWWSBYxViSJiR+8mWrFmpjkZlt8idIduSTYOt8CoRzTxMO+arnxB3a0B2M3DiXwGvhSEvVW/oLTq+Pcde+h/acPmsBRISAkpO/VXv/fvfRmvUej8ALfYIyjXU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=d+R5itD5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="d+R5itD5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D6ED1F00A3D; Fri, 4 Sep 2026 06:01:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501700; bh=ImY+heLHJcm9QsqMfavv0Eh97dE5pGECIQNcqileaWg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=d+R5itD5lD2SnZlAEGOCQe+5tAkRS0Bky1eQ3gZkPSNKaVnRAyyGTiOnakMksasN1 8/iU2QK4dEqXHjilIbwDzvwLb+fj/AJYB5FtprWUANtcJnVVrq0iP6aKKBhJW+Hdqd oiorIA2yzO+TaNnYn6bIrvtDvqY8WSuIHtVhVLxA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nathan Chancellor , "Mike Rapoport (Microsoft)" , Kees Cook , Bill Wendling , Justin Stitt , Nick Desaulniers , Andrew Morton Subject: [PATCH 6.18 503/552] arch_numa: avoid false positive fortify warning in setup_node_to_cpumask_map() Date: Fri, 4 Sep 2026 07:01:00 +0200 Message-ID: <20260904045802.054703817@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nathan Chancellor commit f2b1cb39d5ccab090d8353788f186f7e7a1fffd4 upstream. When building ARCH=riscv using clang with CONFIG_FORTIFY_SOURCE and CONFIG_UBSAN_BOUNDS enabled, CONFIG_NR_CPUS > 64, and the default value of 2 for CONFIG_NODES_SHIFT, there is a compiletime warning from the fortify routines. In file included from mm/arch_numa.c:11: In file included from include/linux/acpi.h:14: In file included from include/linux/resource_ext.h:11: In file included from include/linux/slab.h:17: In file included from include/linux/gfp.h:7: In file included from include/linux/mmzone.h:8: In file included from include/linux/spinlock.h:60: In file included from include/linux/interrupt_rc.h:17: In file included from include/linux/smp.h:13: In file included from include/linux/cpumask.h:11: In file included from include/linux/bitmap.h:13: In file included from include/linux/string.h:383: include/linux/fortify-string.h:430:4: warning: call to '__write_overflow_field' declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribue-warning] 430 | __write_overflow_field(p_size_field, size); | ^ include/linux/fortify-string.h:430:4: note: called by function 'fortify_memset_chk(unsigned long, unsigned long, unsigned long)' include/linux/bitmap.h:248:3: note: inlined by function 'setup_node_to_cpumask_map' 248 | memset(dst, 0, len); | ^ include/linux/fortify-string.h:462:25: note: expanded from macro 'memset' 462 | #define memset(p, c, s) __fortify_memset_chk(p, c, s, \ | ^ include/linux/fortify-string.h:453:2: note: expanded from macro '__fortify_memset_chk' 453 | fortify_memset_chk(__fortify_size, p_size, p_size_field), \ | ^ include/linux/fortify-string.h:430:4: note: use '-gline-directives-only' (implied by '-g1') or higher for more accurate inlining chain locations 430 | __write_overflow_field(p_size_field, size); | ^ 1 warning generated. In this configuration, MAX_NUMNODES is 4. clang unrolls the for loop in setup_node_to_cpumask_map() past this, which triggers the fortify check when accessing node_to_cpumask_map on the theoretical fifth loop iteration because it would be an out of bounds write. Make it clear to clang that nr_node_ids is bounded by MAX_NUMNODES due to the logic in setup_nr_node_ids() by early returning in setup_node_to_cpumask_map() should that condition be violated. Link: https://lore.kernel.org/20260813-arch_numa-avoid-fortify-warning-v2-1-093ad97a78df@kernel.org Signed-off-by: Nathan Chancellor Closes: https://github.com/ClangBuiltLinux/linux/issues/2174 Reviewed-by: Mike Rapoport (Microsoft) Cc: Kees Cook Cc: Bill Wendling Cc: Justin Stitt Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Signed-off-by: Andrew Morton Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman --- drivers/base/arch_numa.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/drivers/base/arch_numa.c +++ b/drivers/base/arch_numa.c @@ -105,6 +105,18 @@ static void __init setup_node_to_cpumask if (nr_node_ids == MAX_NUMNODES) setup_nr_node_ids(); + /* + * This check should never be true but it makes it clear to compilers + * that node_to_cpumask_map is bound by nr_node_ids, avoiding false + * positive fortify warnings when accessing node_to_cpumask_map in the + * for loop below. + */ + if (unlikely(nr_node_ids > MAX_NUMNODES)) { + pr_err("nr_node_ids (%u) is larger than MAX_NUMNODES (%u)\n", + nr_node_ids, MAX_NUMNODES); + return; + } + /* allocate and clear the mapping */ for (node = 0; node < nr_node_ids; node++) { alloc_bootmem_cpumask_var(&node_to_cpumask_map[node]);