From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from submarine.notk.org (submarine.notk.org [62.210.214.84]) (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 C71EA3B19F; Thu, 18 Dec 2025 23:15:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.210.214.84 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766099728; cv=none; b=B7pjcaurol017c1FBylJzujM+azY3LW089tNhFMlSr7qKh+IlHpD7SnfvH0oxC2hKs7l89vIMcxmDSJTzu/+Vin8mQmuMsTvmaviBkzNUi/Lzn1BTXdOcOirjV4r+D2t8Yvscz2C8gybXCba+qdevBHKn8mpqurlG83p+2SjZ+0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766099728; c=relaxed/simple; bh=0cXC7QjWlndFHEB9Cv8hYNwGfUMJZWFXnRG1l2g4zpQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AOmNGlUw7u77HNhN/ldLwp0Jq6AjmyfUpDrqyi2J7ev65EvePBRRL0zAFeZeQJj48wwTvpGJZapK0GBpr00CNJMhKPc48x9Ttg67cfJd/kVDq+q+SKlI3B+wwCC9SBLOrg8Zof8CYdjgFJTqmR1QSb0pUmGHuCC1SPSGWMvmBlE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=vb7jV33G; arc=none smtp.client-ip=62.210.214.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="vb7jV33G" Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id C984D14C2D6; Fri, 19 Dec 2025 00:15:14 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1766099717; 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=AhlYdIZTXXwmG9n/yzVcLdOMymxzvZf2QcspbdE27d4=; b=vb7jV33GUhbfTV4t0gJxrwGehY4rMw0juDjwPN85KpZ29jGo5vroHzhG25H8UJBmmPwKkG aoGTpNj1VLGYpGuapoMGqxQuXPknHDI5lJBzbePosZu93WCOI1pTnuoJSTZ3NCZskaFwme y3MLKJoDLFRyjTGvPKxQd2W4IAP+wPLwjEN97nC6xdgRiN533irPavMBQSAyHS58ula9jP 5dHwJEbIXBm7vc1DtcGeY372BnDbvRRXlPInnTAxa9GPKxXvOa/EBBVChqeo6Jbloh+Ylu lkiLnKm0hd8frdRpTdc9DBJv+bjr6u3/ecBO5frWpNRlV/UKKKSS9NnFMxzUVQ== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id c5d6a9fc; Thu, 18 Dec 2025 23:15:13 +0000 (UTC) Date: Fri, 19 Dec 2025 08:14:58 +0900 From: asmadeus@codewreck.org To: Christian Schoenebeck Cc: Eric Van Hensbergen , Latchesar Ionkov , Chris Arges , v9fs@lists.linux.dev, linux-kernel@vger.kernel.org, David Howells , Matthew Wilcox , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] 9p/virtio: restrict page pinning to user_backed_iter() iovec Message-ID: References: <20251210-virtio_trans_iter-v1-1-92eee6d8b6db@codewreck.org> <8622834.T7Z3S40VBb@weasel> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <8622834.T7Z3S40VBb@weasel> Christian Schoenebeck wrote on Thu, Dec 18, 2025 at 04:14:45PM +0100: > > Won't be the first time I can't reproduce, but what kind of workload are > > you testing? > > Anything that might help me try to reproduce (like VM cpu count/memory) > > will be appreciated, corruptions are Bad... > > Debian Trixie guest running as 9p rootfs in QEMU, 4 cores, 16 GB. > > Compiling a bunch of projects with GCC works fine without errors, but with > clang it's very simple for me to reproduce. E.g. just a very short C++ file > that pulls in some system headers: > > #include > #include > #include > > Then running 3 times: clang++ -c foo.cpp -std=c++17 > > The first 2 clang runs succeed, the 3rd clang run then always blows up for > anything else than cache=none, various spurious clang errors on those system > headers like Thanks, I can't reproduce with this example, but building linux with `make LLVM=1` does blow up on debian... even with cache=none actually? I couldn't reproduce running the same rootfs directory in a container so I don't think I corrupted my image, it appears to be reading junk? short reads perhaps?... (Interestingly, it doesn't seem to blow up on an alpine rootfs, I wonder what's different...) I'm now getting late for work but at least there's something I can reproduce, I'll have a closer look ASAP, thank you. -- Dominique Martinet | Asmadeus