From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5C2A7314B63 for ; Fri, 10 Apr 2026 17:36:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775842572; cv=none; b=EotkqindAJ+G2LFB4k6/BlV4aK8o6DHGPbbEjNnU1xV1EP3GUkAlLVIu8NgXC6YKy0CYI+zy4CWkmBc1dXfY3qm4DLSCB/fu8EdOc3koes83kYh9eC91tNjZxeMBIoRVyNrNhfzWxhghSE4qBBgELKgD+gZFeUKgPSsSs8G9FFI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775842572; c=relaxed/simple; bh=w5CSfo+B+p7ju7y7kIOUBq5rotxu3MgibD84jHHe6rY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AmSDfXonFFzg/qLHXEipXbObM3soHFvi4hIlOgeIqsZIx2ss8flKlac83e5slRU5TDEIX3/drPg7NAwdx+sdx5qXLz7jQQIzmm+0qch0QIz/Jmkbd4ZE1aqUTZeDv+HUcb4kz4pv9B2wCFgPt0QkthGlpyxtqGdbhRpeP5SxV0o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=a6wjT0qn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="a6wjT0qn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 988FBC19421; Fri, 10 Apr 2026 17:36:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775842571; bh=w5CSfo+B+p7ju7y7kIOUBq5rotxu3MgibD84jHHe6rY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=a6wjT0qnBfhrIKpYm/b75wc4wcscEiQxo9GnxbHQI4I6qoVto/CRXEeE+OpXQzijZ SAEWvgCroZPq7GCL9zzaAASb6plzWgsRdi9S3c3ozVzXq6dwWXEq3sN3kWIthEPM4U ZhYfbfFjuj8gIEZwLtZWVToSp5PIvWXH+qcnLlaucviYc4bb0JB3dqV/VNUdM+cmKP +oi/7uacRRLzuo0zaDkDpnNIRQB/zovSVglvUCBH8puArQAQVLqljXxS4wB04d+Rr2 yiXc25n6OQkIu+sg81wat6L2nGV6jTT9eGtQhRpTYrFbiKDuRbhmmKIlGjkDGgfcQY 3L7DROTEETp0w== Date: Fri, 10 Apr 2026 07:36:10 -1000 From: Tejun Heo To: Breno Leitao Cc: Lai Jiangshan , linux-kernel@vger.kernel.org, kernel-team@meta.com, kernel test robot Subject: Re: [PATCH] workqueue: validate cpumask_first() result in llc_populate_cpu_shard_id() Message-ID: References: <20260410-workqueue_fix_nios-v1-1-abbb26575b1b@debian.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hello, On Fri, Apr 10, 2026 at 03:42:00AM -0700, Breno Leitao wrote: > @@ -8318,7 +8319,17 @@ static void __init llc_populate_cpu_shard_id(const struct cpumask *pod_cpus, > * The siblings' shard MUST be the same as the leader. > * never split threads in the same core. > */ > - cpu_shard_id[c] = cpu_shard_id[cpumask_first(sibling_cpus)]; > + leader = cpumask_first(sibling_cpus); > + > + /* > + * sibling_cpus cannot be empty here since 'c' > + * is always set in it. This check silences a > + * compiler warning about using the unchecked > + * cpumask_first() result as an array index. > + */ Can you add more details on the warning and update the patch desc accordingly? This only triggers on UP configs, right? Thanks. -- tejun