From nobody Sat Feb 7 22:21:26 2026 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.19]) (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 394A4212FB3 for ; Sat, 1 Nov 2025 03:10:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.19 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761966654; cv=none; b=ZvT6jOCELEhBkAmxjkwa9xB9fAftTlNHoB3FGG5mNFKYfMKuKpK/42c7Z6kAukeVUJ9ERAY3mAATwe7O6205JQ1Dii13fgHVz1sGOidx5X5eCbNIzLsUgHlHSOFRj00PJ0/DAEwcXsBiF/svPoTzuKQovHfgdQC5O+xXNfnEcaI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761966654; c=relaxed/simple; bh=e2ppcsw5vrnDLhjG9IG7t1gIPzbTAfc/eHNpnig1wk0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=eS39uw9w9xQCu+M/H85O/HxCw+RmRqt6/aNaI6yuJPXGx1UJplTXVqIwepP2S0z8jqZgTGnQtA/pKmH2Shsq4zKlOB4LdKlqHEe5Z63VW5tmE+1fgRExeIwvDe35uG1Q8/n/ZzaLMY/s3DanQwClxO2wWFNhzWlzTRtUVT+kPFA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=YE4GI8Fm; arc=none smtp.client-ip=192.198.163.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="YE4GI8Fm" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1761966652; x=1793502652; h=from:date:subject:mime-version:content-transfer-encoding: message-id:to:cc; bh=e2ppcsw5vrnDLhjG9IG7t1gIPzbTAfc/eHNpnig1wk0=; b=YE4GI8FmdYpuGWRphBlr39nCi7jXODjr1tDMRBNTOEMbqozGats2/XtX fOheM+/e5f29KdMAeRCzQ9rrms6bHT46jBcf6OnU5CppmE6fzYIHG0ysh xSlDrPH099XV3EOQauzGZhpAuxIpyvfCepx5zm6zBFTAs/6SD6qLvKyu1 hrSc9Zk93RJ0L5uyn9RcyhgJi9G8sGant4XZDUkLwpJ9gxOQnMK5NMR+u aOAO1t502YrLHUdC3a13W4TxEdQU3R7Q8uCTx6Z2rx0lUOC0VaK4ixU0k Qj14AmXS4eysxg6orl81c7yHsGL0ddgsP9jySo+SpskuhR+GEU8EAuXIU w==; X-CSE-ConnectionGUID: bH5VbRRjTaCbbZ7QyyNEIQ== X-CSE-MsgGUID: RhsVU7RNQl24Ly4fVfkmVw== X-IronPort-AV: E=McAfee;i="6800,10657,11599"; a="63150983" X-IronPort-AV: E=Sophos;i="6.19,271,1754982000"; d="scan'208";a="63150983" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2025 20:10:51 -0700 X-CSE-ConnectionGUID: brsDFrXqQZyA3pHE3hW02g== X-CSE-MsgGUID: rZe12tLERJGkgMLJnoKVNA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,271,1754982000"; d="scan'208";a="190727873" Received: from unknown (HELO hyperion.local) ([10.243.61.29]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2025 20:10:51 -0700 From: Marc Herbert Date: Sat, 01 Nov 2025 03:10:24 +0000 Subject: [PATCH] x86/msr: add CPU_OUT_OF_SPEC taint name to "unrecognized" pr_warn(msg) 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="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251101-tainted-msr-v1-1-e00658ba04d4@linux.intel.com> X-B4-Tracking: v=1; b=H4sIAB96BWkC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyDHUUlJIzE vPSU3UzU4B8JSMDI1NDA2MD3ZLEzLyS1BTd3OIiXZM0k9Rki8TkFEvTZCWgjoKi1LTMCrBp0bG 1tQCWKB+3XQAAAA== X-Change-ID: 20251030-tainted-msr-4f4ec8acd95c To: "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: linux-kernel@vger.kernel.org, Marc Herbert X-Mailer: b4 0.15-dev While restricting access, commit a7e1f67ed29f ("x86/msr: Filter MSR writes") also added warning and tainting. But the warning message never mentioned tainting. Moreover, this uses the "CPU_OUT_OF_SPEC" flag which is not clearly related to MSRs: that flag is overloaded by several, fairly different situations, including some much scarier ones. So, without an expert around (thank you Dave Hansen), it would have been practically impossible to root cause the tainting from just the log file at hand. Fix this by simply appending the CPU_OUT_OF_SPEC flag to the warning message. This readability issue happened when staring at logs involving the Intel Memory Latency Checker (among many other things going on in that log). The MLC disables hardware prefetch. Signed-off-by: Marc Herbert --- arch/x86/kernel/msr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c index e17c16c54a37..21355130cc78 100644 --- a/arch/x86/kernel/msr.c +++ b/arch/x86/kernel/msr.c @@ -98,8 +98,8 @@ static int filter_write(u32 reg) if (!__ratelimit(&fw_rs)) return 0; =20 - pr_warn("Write to unrecognized MSR 0x%x by %s (pid: %d).\n", - reg, current->comm, current->pid); + pr_warn("Write to unrecognized MSR 0x%x by %s (pid: %d), tainting %s\n", + reg, current->comm, current->pid, taint_flags[TAINT_CPU_OUT_OF_SPEC].des= c); pr_warn("See https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/= about for details.\n"); =20 return 0; --- base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa change-id: 20251030-tainted-msr-4f4ec8acd95c Best regards, -- =20 Marc Herbert