From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 89B0D2C3254 for ; Thu, 14 Aug 2025 11:23:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755170617; cv=none; b=BbjgMVogfpu71PMaiv38mcYrI/Ji8E5aF4RcR81m6Lz2Empay7zAVck/7lOrzvwKd6n9BQfTOQHoQkDeysstcMIl0XIMlagttLdxGuPDzOP9ItteN3mvT2AV/dRzp46QYnYz3rifOEwKP6CY0E2uY+8wv/qCE4S6+nqOVn5dx0s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755170617; c=relaxed/simple; bh=HhEhJKRgB5ddmEmTuM79qCI5EO0LMX7gbVAgUkM1HKE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SNUP8xXw4b/guJwIlV7Tb2O2LyDR3cyUie9QEnge1GqxGTDTlJafHgi3ep9ohumP6xxAD9V2qpIA0GBfknD5dszV4v5DX7DIrDF25fd0L5sCWKzDu11jRCU1E5xw+reIs1u1WUt9ESPdE+riZAmEmt9D9rFXSNbsjbLQ4oWqPnw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=Cv2nmiHN; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Cv2nmiHN" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=FOIBf4BvqOwTh7/DswQxWmanob5JJzJTMvHkH4v9WWM=; b=Cv2nmiHN4RELTEdfyzJV1ptcwP 86bkkeXcOAidEhfuMDgpvfnM5hehOuzsqvnhPxqMxOizu1FFcboeOO2AoHfbBue9Ktq7TGeH2yRmR DCN6cskNNOOQIOmx9acUPTt3DVsUVVSUy8L1JzElvRqCYYLnwuW9/B1qBN0FUO8LCf3TGTamGI8mc TVjRhpD+xNArpLgfYDc0AURFVqfgMuSZrLIF51e9KWoUMHOmfh3g3E/k7VagBFXmxkqoHuGo+ySSO dtReoNKaj4nstj14UJd1AVLzOprXnYAhyVjM3Nw4Zl3hQdG2vYpZs8lEI6a0OwbtDu0fz2F3LY9pk Bjtc3AbQ==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1umW3O-0000000GN0h-0cxA; Thu, 14 Aug 2025 11:23:30 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id EE4603002C5; Thu, 14 Aug 2025 13:23:28 +0200 (CEST) Date: Thu, 14 Aug 2025 13:23:28 +0200 From: Peter Zijlstra To: x86@kernel.org, "H. Peter Anvin" Cc: kees@kernel.org, alyssa.milburn@intel.com, scott.d.constable@intel.com, joao@overdrivepizza.com, andrew.cooper3@citrix.com, samitolvanen@google.com, nathan@kernel.org, alexei.starovoitov@gmail.com, mhiramat@kernel.org, ojeda@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] x86,ibt: Use UDB instead of 0xEA Message-ID: <20250814112328.GC4068168@noisy.programming.kicks-ass.net> References: <20250814111732.GW4067720@noisy.programming.kicks-ass.net> 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: <20250814111732.GW4067720@noisy.programming.kicks-ass.net> On Thu, Aug 14, 2025 at 01:17:33PM +0200, Peter Zijlstra wrote: > diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c > index 99444409c026..59f8bf022ec5 100644 > --- a/arch/x86/kernel/cet.c > +++ b/arch/x86/kernel/cet.c > @@ -123,7 +123,7 @@ static void do_kernel_cp_fault(struct pt_regs *regs, unsigned long error_code) > return; > } > > - pr_err("Missing ENDBR: %pS\n", (void *)instruction_pointer(regs)); > + early_printk("Missing ENDBR: %pS\n", (void *)instruction_pointer(regs)); > if (!ibt_fatal) { > printk(KERN_DEFAULT CUT_HERE); > __warn(__FILE__, __LINE__, (void *)regs->ip, TAINT_WARN, regs, NULL); Obviously this is debugging remnant and will go away.