From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 91ACD8F5E; Tue, 15 Apr 2025 16:04:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744733088; cv=none; b=S3VSJEi/k/DEOJLpK0JG/3K5EBMo+Zr0AVVz6MCnrQkWDPjFkyafrZJG8NwhUJXIcEu7zku7zY5wK/OUPOQYUs171DpLn0PnNLwX7rhS/Q2xSTK1lGOd1UM/Cl+oyeWOM1WKHxLCALzBTYgn0eOvNr1ZVLfjgiPKlj1DRfmWlHA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744733088; c=relaxed/simple; bh=c3FUuYd3kYrMaDwyBGr0+2LAYsCrdsIaFI817Klmviw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PfnAAn0jLenjpGUWq1JqT9EOqyGXDygXVIiJzY8nahVNw29hv2RhtmAwE/qnkA4jJHD1bumUalkwaIQ6vrBZ2iySyOFjUnuhyX6JbGXKozsDx5uhc3Uk+8LuLqZ2Fte9OMAAiD23WCdnTMYFAUcxWS2y88+dfcyS5awl3q8MDO4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CmFZ2KgP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CmFZ2KgP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0165C4CEEB; Tue, 15 Apr 2025 16:04:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744733088; bh=c3FUuYd3kYrMaDwyBGr0+2LAYsCrdsIaFI817Klmviw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CmFZ2KgPPt8MXnBUOIAnpFDibyn2J0OOB6BPUm7Q1LUYjZA3pe8tQ13RPF8X2g3wb Q5Mf2obobpyJ10/Mn1w1Qbm9l78zJxfAj5mf+4p6Ivj52XArFlmSKmTvOtf2EvEvDU aYAdlM3O3vG7cpx5o/7yLzn8v1ETFPQ2snDrOXTBHiwOjCD5sGvTINhV764iu9w7RT 1B5FfVnOIKHW0j2fCs8p3p4reswpDHX9MEUQG4mWoRsSjM0/CIxxpoRsOcehPXQGir OeYWEWCOZv9sBhtYPzSbp72KJkgHdpD4OO7/mb4vH9dK7rQyt+MnlhEMRTW1UIvH2I 6khmLyxLxyh4w== Date: Tue, 15 Apr 2025 09:04:44 -0700 From: Kees Cook To: Nathan Chancellor Cc: Josh Poimboeuf , kernel test robot , oe-kbuild@lists.linux.dev, Peter Zijlstra , linux-kernel@vger.kernel.org Subject: Re: drivers/bluetooth/hci_vhci.o: error: objtool: vhci_coredump_hdr(): STT_FUNC at end of section Message-ID: <202504150903.9F943DB0E@keescook> References: <202504130652.o7UWcPMe-lkp@intel.com> <20250415003021.GA4163917@ax162> 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: <20250415003021.GA4163917@ax162> On Mon, Apr 14, 2025 at 05:30:21PM -0700, Nathan Chancellor wrote: > Hi Josh, > > On Mon, Apr 14, 2025 at 05:18:08PM -0700, Josh Poimboeuf wrote: > > On Sun, Apr 13, 2025 at 06:16:42AM +0800, kernel test robot wrote: > > > :::::: > > > :::::: Manual check reason: "only suspicious fbc files changed" > > > :::::: > > > > > > BCC: lkp@intel.com > > > CC: llvm@lists.linux.dev > > > CC: oe-kbuild-all@lists.linux.dev > > > CC: linux-kernel@vger.kernel.org > > > TO: Josh Poimboeuf > > > CC: Ingo Molnar > > > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > > head: b676ac484f847bbe5c7d29603f41475b64fefe55 > > > commit: 3e7be635937d19b91bab70695328214a3d789d51 objtool: Change "warning:" to "error: " for fatal errors > > > date: 12 days ago > > > :::::: branch date: 2 hours ago > > > :::::: commit date: 12 days ago > > > config: x86_64-buildonly-randconfig-001-20250413 (https://download.01.org/0day-ci/archive/20250413/202504130652.o7UWcPMe-lkp@intel.com/config) > > > compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247) > > > rustc: rustc 1.78.0 (9b00956e5 2024-04-29) > > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250413/202504130652.o7UWcPMe-lkp@intel.com/reproduce) > > > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > > > the same patch/commit), kindly add following tags > > > | Reported-by: kernel test robot > > > | Closes: https://lore.kernel.org/r/202504130652.o7UWcPMe-lkp@intel.com/ > > > > > > All errors (new ones prefixed by >>): > > > > > > >> drivers/bluetooth/hci_vhci.o: error: objtool: vhci_coredump_hdr(): STT_FUNC at end of section > > > > This is looking like a Clang bug to me. .text.vhci_coredump_hdr has > > zero bytes, and its zero-length vhci_coredump_hdr() function is > > referenced by force_devcd_write() as a function pointer. I wasn't able > > to find any undefined behavior that might trigger that somehow. > > Indeed, this is https://github.com/ClangBuiltLinux/linux/issues/2073, > which does have a fix in LLVM 21 now: > https://github.com/llvm/llvm-project/commit/ea2e66aa8b6e363b89df66dc44275a0d7ecd70ce > > I forgot to request a backport for LLVM 20 but I am not really sure I > want to draw more attention to the patch (since the Clang folks will be > asked to ack a backport) since it had some contention in the LLVM issue > after it was merged: > https://github.com/llvm/llvm-project/issues/130649#issuecomment-2719119408 > > Kees, do you have any thoughts on requesting a backport for that? I don't think we should especially since we can fix the one place it tickles the kernel currently. (And the fix actually improves the code.) > Regardless of it being fixed in LLVM 20, the warning impacts all > supported clang versions IIRC, so we should probably submit Kees's patch > to just use a 'const char *' with the string literals instead of calling > snprintf() on the 80 character array. I'll send the patch... -Kees -- Kees Cook