From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 89A6B1A23B1 for ; Tue, 29 Jul 2025 21:17:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753823866; cv=none; b=Dunwg+kHUTYZyG020k3WEkWhS6Oxvsmt9Vfs22Ni6bgHx2QOVInBYYsgXVaCac3Dk1Dx+1xLarbYp/GyqqBA/iXTDFG/tGphmRnQlqJKfYYdWWrACAU3s21h6izq7TvgDpLFWKm3LS2fzZD7lLQmh+jFNkbPyvbcrCMYEFvnOG0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753823866; c=relaxed/simple; bh=im4zcgUfpSPq2ELFn2mVEfTTsSNRnAzpBvs7yc2Zxm0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=V2mvAv19orhtFEBMeNaHIeVCUk5ajFiZkaNVNaQHsiNdD3LUWRRT4TLmnJ3KphAMtbGQHLtENTXmRdb8ryuzBJyrviH3S8s79ZthQHPK8xN6LZbhwe5Sv91RA/qBN/ZadWggHJ9J0d2ugucIo/WCbv0EXhrPMnXT+88NiOYZnls= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=LOQuYbzM; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=7ZNr0A9N; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="LOQuYbzM"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="7ZNr0A9N" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1753823862; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Q5hkoU4bTkfvIy0vP97V2ilntrsjj5Vy72aNaQmKN9o=; b=LOQuYbzMQ0EAS03JkYFeR/B5Q+AaK13a/D03cUHvhFibt9ljm/49B6zavZRGU0pZrQUx7m 5kq3L1X69OOUjndXzKTzH1rJsB3MxRZhyyu5Z8H4s1bFOXe4HKTP6q9Mqw8aTyg8EGnDFV 5aIrN2kIDZ5m6bi8eBVTuzbYWzqme60/3AuI+DCDQQwAAwQBXas6BY2RcoeFPagX5/3TOr 4qE6ScCl0GU71x+TD5Wd2hWyPP98zZZ3CnymzTufWvsWEady9JZYXEShVjapNIAMGicnTa EWD3utoB8TWxDWoSjM0GsJ88c9DWubKweOAaqOCXL0JKMZRifoyukSIEWmDc+Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1753823862; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Q5hkoU4bTkfvIy0vP97V2ilntrsjj5Vy72aNaQmKN9o=; b=7ZNr0A9N5GbWlFkCpGP4zKMKbFLxZG6XOwuwL9/gdGLLpriFoS395oN8m6dkIxMxZDmAzR kEwTJSQTxVIffyBQ== To: syzbot , bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, syzkaller-bugs@googlegroups.com, x86@kernel.org, Kees Cook Cc: Linus Torvalds Subject: Re: [syzbot] upstream build error (23) In-Reply-To: <87cy9ikcwh.ffs@tglx> References: <6888d004.a00a0220.26d0e1.0004.GAE@google.com> <87cy9ikcwh.ffs@tglx> Date: Tue, 29 Jul 2025 23:17:41 +0200 Message-ID: <874iuuk87e.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Tue, Jul 29 2025 at 21:36, Thomas Gleixner wrote: > On Tue, Jul 29 2025 at 06:43, syzbot wrote: > and to keep the call for efi_init() as a symbol for the linker to > resolve, which obviously fails. > > If I change the efi_enabled() stub to __always_inline, it's optimized > out. Kees has addressed similar problems in: 8245d47cfaba ("x86: Handle KCOV __init vs inline mismatches") 65c430906eff ("arm64: Handle KCOV __init vs inline mismatches") c64d6be1a6f8 ("s390: Handle KCOV __init vs inline mismatches") 2424fe1cac4f ("arm: Handle KCOV __init vs inline mismatches") d01daf9d95c9 ("mips: Handle KCOV __init vs inline mismatch") > Disabling CONFIG_KCOV_INSTRUMENT_ALL makes it go away. So GCC confuses > the optimizer when CONFIG_KCOV_INSTRUMENT_ALL is on. Seems to be GCC 12 specific. GCC13 does not have that problem. > The kernel is full of such inline (not __always_inline) stub > conditionals which evaluate to a constant.... And chasing all those stubs and convert them to __always_inline seems to be a whack-a-mole game. Can we just stop pretending that GCC12 is KCOV capable? Thanks, tglx