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 1783822A1EF for ; Thu, 27 Feb 2025 12:22:32 +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=1740658953; cv=none; b=ScIDgz7ba8OwzCBVoyjY4X5prW83g7172u2f6FJqwumYyxouUyW2Kw+0+Rr/FQnObGItnpjGRQTyZouJJ/0MuWK2AQvT1C1+1kccwmPtwrcAwSGp6HRAuqUacKVSkL9v/cKu9s7aqQCBpNzMo4FRXdxXZHz3HQCiMuA6Nc9gg+8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740658953; c=relaxed/simple; bh=cVpzKkyBYmpvEbCcTYlxi5MAHKPz41ZFptazsq1Sxxg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GC5m5dvTfgBBwjhN8vK08iUQZxdk2f9WOWPVtMivJU7mki1p8I1n71nDbSDnkY+t7VpP3NfTFuelSkmUECEqAp8PPdJ0KIEu5mcUybBZ/ldRAbeTkxnXyQpuQ7yaYFKWAoo4Cg7/xpb64omNs2vkqdrSVD6srS81+VysQheN+t8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YWhr47Bf; 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="YWhr47Bf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F7C6C4CEDD; Thu, 27 Feb 2025 12:22:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740658952; bh=cVpzKkyBYmpvEbCcTYlxi5MAHKPz41ZFptazsq1Sxxg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YWhr47BfjZf78WeGkQQnu9+QY3NjJG+wYL/nLq8M8LqcgB6YsZcXILzTof5zoZjgi shTbf5akpCdeChmZqrcrle1Coco9uJTUgfbS6ZILp/8oS+HkxrYg91DHND7qVpQ0Be PnUVU/9+l9Mpw8ySrE5vPZbF17dYubObE4aT5rL3wZxrfF0FsqQpHKscBHwMT1HysQ bAJrypS1gkK0WKiGULgYmzV+lWzsDTayPWLx5L3zbMryXyCmKQJ2yZJA9lW9ztwn2T 1BiG7zQVACXYVxqV79ysh5WmGc8A1QiQ5HOQca67bPLni2uKGzAhXAnwDJ3U7xHVQz 89USv31LwwcUQ== Date: Thu, 27 Feb 2025 13:22:20 +0100 From: Ingo Molnar To: Uros Bizjak Cc: Matt Fleming , Jakub Jelinek , linux-kernel@vger.kernel.org, kernel-team@cloudflare.com Subject: Re: CONFIG_KASAN triggers ASAN bug in GCC 13.3.0 and 14.1.0 Message-ID: References: <20241213190119.3449103-1-matt@readmodwrite.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: * Uros Bizjak wrote: > On Mon, Dec 16, 2024 at 5:20 PM Matt Fleming wrote: > > > > On Sat, Dec 14, 2024 at 1:17 AM Uros Bizjak wrote: > > > > > > Does your config include CONFIG_UBSAN_BOOL=y ? > > > > Yes, it does! > > > > > There is a rare interaction between CONFIG_KASAN and CONFIG_UBSAN_BOOL > > > (aka -fsanitize=bool), reported in [1] and fixed for gcc-14.2 in [2]. > > > > > > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111736#c42 > > > > > > [2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115172 > > > > > > Otherwise, please attach your .config, and I'll look into this issue. > > > > Thanks. Disabling CONFIG_UBSAN_BOOL does indeed make the kernels boot again. > > > > Should CONFIG_UBSAN_BOOL have a dependency on GCC 14.4+ ? > > No, this is a very rare Oops that triggers only with gcc-14.1 version > and only when both KASAN and UBSAN are enabled. This is actually the > problem with sanitization of the percpu address when named address > spaces are enabled (IOW, sanitization of __seg_gs prefixed address). > UBSAN creates a temporary in memory, but forgets to copy memory tags, > including named address space qualifier from the original. Later ASAN > sanitizes this location as a normal variable (due to missing > qualifier), but actually should be disabled for __seg_gs prefixed > addresses. > > Your report is only *the second* since sanitizers were re-enabled with > named address spaces. gcc-14.2 that includes the fix is available > since August 2024, and since sanitizers are strictly development > tools, my proposed solution would be to simply upgrade the compiler to > gcc-14.2 release. So unless this is difficult to test for, it would be nice to have a compiler version cutoff for the feature. Especially if it's been reported twice already, chances are that a lot more people have experienced it already. The kernel build should avoid this known oops automatically. Thanks, Ingo