From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from wout2-smtp.messagingengine.com (wout2-smtp.messagingengine.com [64.147.123.25]) (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 0C58213FFF for ; Mon, 18 Dec 2023 10:12:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arndb.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arndb.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=arndb.de header.i=@arndb.de header.b="RXMU++xD"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="PmbrQi1j" Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.west.internal (Postfix) with ESMTP id AD92E32003F4; Mon, 18 Dec 2023 05:12:32 -0500 (EST) Received: from imap51 ([10.202.2.101]) by compute5.internal (MEProxy); Mon, 18 Dec 2023 05:12:33 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-transfer-encoding:content-type:content-type:date :date:from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to; s=fm1; t=1702894352; x=1702980752; bh=3ZyUug5xi/z8ZT7W43WlY1pfaZKNZzJDM3Pip8YjDvY=; b= RXMU++xDlQ6Rrti2xmG4o9C3g0x2w29JWi+1DPsZIbZQqpOijq6KGUk4VFkVoqbu bo8RxTXlEzXU+q5uVyr1YuXzdb6CptioQNC2luTSshIUfmn7LtQEvgy/zy6HfdKv Lu+CTVLN9tjTF/uxm7rzdCpSO00MLXi3SPQZhk1VXY6iaFUSidResSlBdHwMhf8B DeFdwPsTyP5s+LY1BlxwLyyE1E+FGKWhet/pqXsVcjOblxuLBInZhxskLifhM7W1 9JU8/qVp9v1NcrGu+7OY8l+ZX10s07nr3fb6A6gSIztkv20Vlb6VycgQ3ZACvRX0 kIRZEizPFlt407k6L0O9TQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:content-type:date:date:feedback-id:feedback-id :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm2; t=1702894352; x= 1702980752; bh=3ZyUug5xi/z8ZT7W43WlY1pfaZKNZzJDM3Pip8YjDvY=; b=P mbrQi1j0V9yqQ6sVCO9zM4NB7ShsVu5jg6j5DHHIHTvs+WPvNdNl6/xwhrxvTjd4 eAk6Kvtbj/0AfWGlHa3r7LtFfvMreZvxWwSpYbSkwvfIS9czXlrqF3oe6fEL4CZ7 c1USfgUc2l1qG8sRnvhKzqIVofRZ2j+W2U5MF1cKXNw9FKZenzMBULtvkdAX8yhK MpOQDu+eawyBHdoBRFudmr3ttKvhKc1ks/bQv1SY9N2CVzvxOTCX8cHynM0XMFuT nED0/qYShaqLq7g1kIGPL7VD8ALgWXojFbrEh4XTgXENO4pFzW019itgz62VkBGo dhyxbM8SxhhA3S+nPfyYg== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvkedrvddtkedguddtucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtgfesthhqredtreerjeenucfhrhhomhepfdet rhhnugcuuegvrhhgmhgrnhhnfdcuoegrrhhnugesrghrnhgusgdruggvqeenucggtffrrg htthgvrhhnpefgkeeuleegieeghfduudeltdekfeffjeeuleehleefudettddtgfevueef feeigeenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecuvehluhhsthgvrhfuihiivg eptdenucfrrghrrghmpehmrghilhhfrhhomheprghrnhgusegrrhhnuggsrdguvg X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id C010FB6008D; Mon, 18 Dec 2023 05:12:31 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.9.0-alpha0-1283-g327e3ec917-fm-20231207.002-g327e3ec9 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: In-Reply-To: <3fb66648-5581-4371-b15e-23e52e6469ba@t-8ch.de> References: <202312171924.4FozI5FG-lkp@intel.com> <3fb66648-5581-4371-b15e-23e52e6469ba@t-8ch.de> Date: Mon, 18 Dec 2023 10:12:03 +0000 From: "Arnd Bergmann" To: =?UTF-8?Q?Thomas_Wei=C3=9Fschuh?= , "kernel test robot" Cc: oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, "Jakub Kicinski" , "Simon Horman" Subject: Re: include/linux/compiler_types.h:397:45: error: call to '__compiletime_assert_810' declared with attribute error: BUILD_BUG_ON failed: skb_ext_total_length() > 255 Content-Type: text/plain;charset=utf-8 Content-Transfer-Encoding: quoted-printable On Sun, Dec 17, 2023, at 17:13, Thomas Wei=C3=9Fschuh wrote: > +Cc Arnd who was taking care of CFLAGS_GCOV in the past. > > On 2023-12-17 19:39:34+0800, kernel test robot wrote: >> | Closes: https://lore.kernel.org/oe-kbuild-all/202312171924.4FozI5FG= -lkp@intel.com/ >>=20 >> All errors (new ones prefixed by >>): >>=20 >> In file included from : >> In function 'skb_extensions_init', >> inlined from 'skb_init' at net/core/skbuff.c:4848:2: >> >> include/linux/compiler_types.h:397:45: error: call to '__compileti= me_assert_810' declared with attribute error: BUILD_BUG_ON failed: skb_e= xt_total_length() > 255 I tried to count the actual number of bytes and got to a worst case of 2= 00 bytes (for 64-bit machines), but this may have been wrong. I can think o= f two possible things that may have caused the problem: a) there is an actual overflow but gcc fails to realize it without GCOV b) the compile-time calculation goes wrong and is no longer a constant value, so the assertion fails to evaluate We can probably elinminate a) if you can show that raising the limit does not avoid the problem. > [..] > > This seems to be a compiler bug/configuration issue. > > When I remove the entry for SKB_EXT_MCTP from skb_ext_type_len then the > error goes away. However this entry works the same as all other entrie= s. > > Also dropping -fno-tree-loop-im *or* -fprofile-arcs from CFLAGS_GCOV > makes the code compile as-is. > > Or switching to a 64bit build... The -fno-tree-loop-im option would likely stop the loop from getting unrolled, which is how the skb_ext_total_length() return code is no longer constant. Does manually unrolling this loop avoid the problem? Arnd