From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 4A4E022A4EB for ; Fri, 27 Jun 2025 07:59:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751011154; cv=none; b=so72ZcCPkpxOVXsY0zHUqyiH4yeFG66byH62f3gcwHdi0AuuWZMf4A83eariidkTehjQ4mRdxl1gqQ+LJwsXNpqkgc0rBlhEyYE371jibfH4E8nXAEeOTgE5mfRovGeBMv8JtXzz9Fj5aEkEm/eRL3/kH+YXC/kvuEZq51Q38OQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751011154; c=relaxed/simple; bh=L+ZZOa8XaEDSQVrNy6HRtl+1pHVA46x0IEJzjJWdT4s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E6+sJG5bRcVsEmD/PdN+6BDniYmczblkBxFQjiO6cbGBRCS9TX2k1+N/Fd1vvEVCJH6NLhAeRhtib25zRfQ7jB8qUm2T0NRgcwjDPiHa35x4klViEYcZheZ8qPxS0PDWlcbNBK5Vbwc6m/loZpz6IQ6qDzSNVXH4Uj/9WqU0i+4= 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=l379TvQw; arc=none smtp.client-ip=90.155.50.34 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="l379TvQw" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=L+ZZOa8XaEDSQVrNy6HRtl+1pHVA46x0IEJzjJWdT4s=; b=l379TvQwZ7I3IbWLgSb7fEoVrj ghJI3dvzRdZx54yKEXp9F9uSCGtubRtXMDKd/AQpDjBx0DGOOOyvunPHVg9frVimsNdf2EuuHNNga 2KFF8vXCJWDE4zHJqzmiCHydWAdGJvhQjlc2h5AZZQdcUvFvTYzgM+ADb8dGM8TRuawPDat9CSLk+ EqFTz9c4uRXLagew77YMYETmxwdpC6coq88g8Sa/kH+UVpKaSUSOujdwc1LFqavz8oyMlHTUmXX2T YkGAPE1O+9CCsgsXG5jh4yXPW4d9DgafA3BqY0wJSemK3NiShFQ3foNM1fUus6UD+GWbwGtXrPaRj 4MVndI4w==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uV3zG-0000000DYTh-1NGh; Fri, 27 Jun 2025 07:59:06 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id DDCA1300222; Fri, 27 Jun 2025 09:59:05 +0200 (CEST) Date: Fri, 27 Jun 2025 09:59:05 +0200 From: Peter Zijlstra To: Alexander Potapenko Cc: quic_jiangenj@quicinc.com, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Aleksandr Nogikh , Andrey Konovalov , Borislav Petkov , Dave Hansen , Dmitry Vyukov , Ingo Molnar , Josh Poimboeuf , Marco Elver , Thomas Gleixner Subject: Re: [PATCH v2 01/11] x86: kcov: disable instrumentation of arch/x86/kernel/tsc.c Message-ID: <20250627075905.GP1613200@noisy.programming.kicks-ass.net> References: <20250626134158.3385080-1-glider@google.com> <20250626134158.3385080-2-glider@google.com> 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: <20250626134158.3385080-2-glider@google.com> On Thu, Jun 26, 2025 at 03:41:48PM +0200, Alexander Potapenko wrote: > sched_clock() appears to be called from interrupts, producing spurious > coverage, as reported by CONFIG_KCOV_SELFTEST: NMI context even. But I'm not sure how this leads to problems. What does spurious coverage even mean?