From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 58B7837DE9C for ; Mon, 27 Apr 2026 19:55:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777319717; cv=none; b=T8VCPVyUpBS1ZRq8xpGXa/AH99h6+OWyDcQYhjlhKTsZgMgR7J1AkAzuxxiDewqaHXs5NEwj+xGhMsjtYkvcp7eh1RAHesDJIR1MKjSAbOzI331S0rS+5ZgIE5z05mMhqopH0MnMj40y8wxcgCH1RqoTd2W2fYIOYLtUViMIZ9M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777319717; c=relaxed/simple; bh=8LpaDaVt9mwNydvoEZ8VY0/GGcrwvFfo/bFwDGbEy2E=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=S+zV6a4H477lI/m94MLZDVdxlZl/DStByqHbuHC0+f4GdIpuN6HwPUPBRMs5b3TVQVeeSIirBVt92KK8kAueM+0By9Rlv2RVnjdDqwkLO0pHBtFeMM8qkC90+J4cnFN6XfZbXWNyLuXsr2WGm0TLWoVQzuzGLFC/ef67VKKuYM0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=PvGNPytT; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="PvGNPytT" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-bce224720d8so6029910a12.1 for ; Mon, 27 Apr 2026 12:55:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1777319715; x=1777924515; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=RqWYKvnn5RtqHUlMoDJt0jUZpl9WLFhzeTaq5iPf3eo=; b=PvGNPytTpapGzgyywsVPcVYMoc6aDGljehpfK6WQDQZw034PEdgVofAcA1Nej048JA vivl8SZVeV7TG9wyLhTJD6RwEdaIdpTGtwNYx1wnO1BqbKMeYfa67nZRrQy1+k+MR6FL e4C+zrjZf/6DaayPH7E02iE8PytkUdOOppzuzcmwGPfp5yNJ60aUmog332cVRYEmGNSn Iw0Yz/qB7JeY2SjsT/GkYIFKggesfi6ojHi9EFrnSAjyyi/Dpgv5HJtNo8GTBZHfAS3M MXFGaJSfDwAq0ET5+XW9tDsCSsdyADLPcKwEIrC64nP7LWPWSoIx+NoXZCsE4FAmvQ+3 bQPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777319715; x=1777924515; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=RqWYKvnn5RtqHUlMoDJt0jUZpl9WLFhzeTaq5iPf3eo=; b=RCLZW1A1IHmDf7beqCAkMDYk0mtYUR40YciQiIx0HtUHS6ZZEw4C7/6gywl71SiAkU hpHsaM9STYf2hzA0jEpDmcAtSyqEQR4EwsDdUvU18AlLRNgk+o6p+Xc2ea04LVM9SaDJ sWmWfXbBfrjhxxqcAQxSH/6SIoVlAUKF0hMKYTmp62wzXXl7PRuqCoxoL39Rbvc5dzas vk5irjNiWelq7WHRFIf7QKd2EF8Pd/snfHSBJ5FTZYu/KZqimo7DUrCRS74pCaG/DuxD uifwjGttP7+L18LdWkgLQN+gsRqrE3FRIDWZjJZQPM1B6Gfb8nug1lYfYfsgzkEzoZ7f eiUg== X-Gm-Message-State: AOJu0YxKbpLrDhqPOhQQ9UYACJWXYg+3xLua1kxrW2rza12Z+lMvHF7A Rym6ziuoc/WK0HePZbPHakc0J89GNjSmvaHQnXiRQzNlD+i+gSaGCOKdDUKRk0fz29n0WyLitNT +1SLL0LksxsnTZrkn850jGaPK9nkYlATYwJFXRgw14ME3rboMJQV18wyZ50GspzGXlt4uig+WtR iTNA0QaDUDMsUA34y7MPhKGWmaitVSFCY/J/+rrxU8SGde X-Received: from pfbci14.prod.google.com ([2002:a05:6a00:28ce:b0:82f:7242:4cb9]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:2e11:b0:82c:e1aa:21e3 with SMTP id d2e1a72fcca58-834dc19837cmr394146b3a.10.1777319715245; Mon, 27 Apr 2026 12:55:15 -0700 (PDT) Date: Mon, 27 Apr 2026 12:55:13 -0700 In-Reply-To: <177731670864.3521451.17700947894959847025.tip-bot2@tip-bot2> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260423145419.459988-2-seanjc@google.com> <177731670864.3521451.17700947894959847025.tip-bot2@tip-bot2> Message-ID: Subject: Re: [tip: x86/misc] x86/bug: Add printf() validation to HAVE_ARCH_BUG_FORMAT_ARGS WARNs From: Sean Christopherson To: linux-kernel@vger.kernel.org Cc: linux-tip-commits@vger.kernel.org, Dave Hansen , x86@kernel.org Content-Type: text/plain; charset="us-ascii" On Mon, Apr 27, 2026, tip-bot2 for Sean Christopherson wrote: > The following commit has been merged into the x86/misc branch of tip: > > Commit-ID: 40c4b47f41b95dff743c841536cb64014e65ef0c > Gitweb: https://git.kernel.org/tip/40c4b47f41b95dff743c841536cb64014e65ef0c > Author: Sean Christopherson > AuthorDate: Thu, 23 Apr 2026 07:54:17 -07:00 > Committer: Dave Hansen > CommitterDate: Mon, 27 Apr 2026 12:02:40 -07:00 > > x86/bug: Add printf() validation to HAVE_ARCH_BUG_FORMAT_ARGS WARNs > > Add explicit printf() validation for x86-64's newfangled WARN > implementation, as most (all?) compilers fail to detect basic formatting > issues without the annotation. E.g. even goofs like printing a u64 as a > string aren't detected: > > WARN_ONCE(1, "Bad message, %s", vcpu->arch.last_guest_tsc); > > 32-bit x86 doesn't support HAVE_ARCH_BUG_FORMAT_ARGS and uses generic > implementations that provide printf() validation. This means there's > now a big blind spot is code that is strictly x86-64. Inconveniently, > new features are also frequently x86-64-only. > > Fix the blind 64-bit blind spot. > > [ dhansen: changelog tweaks to flesh out the 64-bit-only details ] Much better than what I wrote, thanks Dave!