From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from submarine.notk.org (submarine.notk.org [62.210.214.84]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 761BB23D7E4 for ; Wed, 13 Aug 2025 04:49:25 +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=1755060569; cv=none; b=LrD5TF3vPQcOcqBcaOcF1fBYik4amQs7FC3JKSUbll4b989BuQKDWtpPYxBup4exoeivoR56tkL+99M5/z7g+IBi6V83xEzjjoKFEm+lT6w3zafru2vko9M+8qM1Crkc6R90FdF3er+qqrjlWL5RcM+3W+jBdgKoSmm9rCv4lD8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755060569; c=relaxed/simple; bh=bINWFcx+i0l+3T/UEIJHibArgyaXAJG8U1O2POFs8tI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DFr+tl3titbwo3Z5j6JKAjGzEfsaKy+BfzMaTLl+peNjGi3TL9FUnuLlozAplh6RN8Fc29CZ9M6SvdtXYMpApj7W7yDJJjRFltXZVTSIu++xIb9QtKKqbBzRxW7fnYON2VU4P408C7lDGGMzizxBNylvT8o78/e7rRz2ItdQFwY= 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=XVbe1UW7; 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="XVbe1UW7" Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id 9D91914C2D3; Wed, 13 Aug 2025 06:49:19 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1755060564; 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=2gYQPNPMmKQR/y69joJ6grvfQ7sb2M14s/jfpiUm4+w=; b=XVbe1UW76zHNmZAYQ87tMsEgOECdFfIgVSw+Fy2jy1ArOng+EKOYVY7d04N44rEwrSxoIO dePoHBHkmwcbHlcRskh5EJ8CFL4DeIU9I8dR1ghoO1A65TnrsHwz8csFGMFPmmRMh4K5fB Fm2nnTeYxWjgm3XxvQFsGAxCMrBFqrqCPGJtcaCAz8Hw1jmQVrBUFDFWJ0GfuBC0qYjEXj Njrq+10uY8Vd2P8LhoiV0aBW2t8yt74TFCEAiTGz8AU4m+Y1QZTDR6A3ywlo4iiDSWlu/g ml2GFm7Z2xbb2wkVSJ9sNeWFZpgXWU1d+u7Q+aVoAvmgqfGLJn4EnbwMexDuQA== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id 3e5818ac; Wed, 13 Aug 2025 04:49:17 +0000 (UTC) Date: Wed, 13 Aug 2025 13:49:02 +0900 From: Dominique Martinet To: Harry Yoo Cc: syzbot , akpm@linux-foundation.org, apopple@nvidia.com, byungchul@sk.com, david@redhat.com, gourry@gourry.net, joshua.hahnjy@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, matthew.brost@intel.com, rakie.kim@sk.com, Eric Van Hensbergen , Latchesar Ionkov , Christian Schoenebeck , syzkaller-bugs@googlegroups.com, ying.huang@linux.alibaba.com, ziy@nvidia.com Subject: Re: [syzbot] [mm?] WARNING in alloc_frozen_pages_noprof Message-ID: References: <689bb893.050a0220.7f033.013b.GAE@google.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 In-Reply-To: Harry Yoo wrote on Wed, Aug 13, 2025 at 09:31:34AM +0900: > The warning is: > > /* > * There are several places where we assume that the order value is sane > * so bail out early if the request is out of bound. > */ > if (WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER, gfp)) > return NULL; > > There's not much the buddy allocator can do when a user requests > order > MAX_PAGE_ORDER allocations. > > > alloc_pages_mpol+0x1e4/0x460 mm/mempolicy.c:2416 > > alloc_frozen_pages_noprof+0xe0/0x210 mm/mempolicy.c:2487 > > ___kmalloc_large_node+0xac/0x154 mm/slub.c:4306 > > __kmalloc_large_node_noprof+0x2c/0x8c mm/slub.c:4337 > > __do_kmalloc_node mm/slub.c:4353 [inline] > > __kmalloc_noprof+0x3bc/0x4c8 mm/slub.c:4377 > > kmalloc_noprof include/linux/slab.h:909 [inline] > > kzalloc_noprof include/linux/slab.h:1039 [inline] > > v9fs_fid_get_acl+0x64/0x114 fs/9p/acl.c:32 > > So... 9p FS shouldn't really request that? > > Cc'ing 9p FS folks. Thanks for the Cc. So, this comes up once in a while, everytime we discuss limiting the xattr size, then someone says we should do something else or I'm using the wrong define or I don't remember and then when I ask what we should do never reply again. See [1] or [2] for the last two time this happened. [1] https://lore.kernel.org/all/20240304-xattr_maxsize-v1-1-322357ec6bdf@codewreck.org/T/#u [2] https://lore.kernel.org/lkml/20240202121319.21743-1-pchelkin@ispras.ru/ I'll be happy to take any patch you send (or one of the older patches if you tell me which is "correct"), I don't care anymore. -- Dominique