From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA532C43334 for ; Tue, 14 Jun 2022 02:08:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352350AbiFNCIo (ORCPT ); Mon, 13 Jun 2022 22:08:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351993AbiFNCGt (ORCPT ); Mon, 13 Jun 2022 22:06:49 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A96C434663; Mon, 13 Jun 2022 19:05:50 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4DE8CB8169E; Tue, 14 Jun 2022 02:05:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEB35C36AFE; Tue, 14 Jun 2022 02:05:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655172349; bh=g6hV2nEfu4q7fWk0v9EQw/74GXzsuzsOm5CE2k8SdLk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WV1B3BWjnbbp+ZS6bZVCISSJik1qJVQtada5i2i/slHyhSKgftk3wwTyqBCa48Oa6 D1VI3htojaAIT1K9wDDSpXJh4KJEtBitMcGxRnza5BzrE8ybVg0Dc0BbKLAF42KQfC qlNmQdpzWwjfDkgjCz2XifXHM9xAzzFwrSOMpy4wDHbPUO86g16mGWxcUWND2u8H7u uGWYCtllPGp/VCeW4FycWdt7254FVzNOuT40RPPkt5o+qCV98Q/rrGkvCB0dInlpR3 varYv69PBQJleT3V6Du49UleAvFeFuktu/pcP/LWt2oEcqznJ4SHF6nhCHI5mo6Djq drSk/tqaThQNQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Linus Torvalds , Kees Cook , David Howells , Sasha Levin , zyan@redhat.com, sage@redhat.com, idryomov@gmail.com, linux-afs@lists.infradead.org, ceph-devel@vger.kernel.org Subject: [PATCH AUTOSEL 5.18 39/47] netfs: gcc-12: temporarily disable '-Wattribute-warning' for now Date: Mon, 13 Jun 2022 22:04:32 -0400 Message-Id: <20220614020441.1098348-39-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220614020441.1098348-1-sashal@kernel.org> References: <20220614020441.1098348-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds [ Upstream commit 507160f46c55913955d272ebf559d63809a8e560 ] This is a pure band-aid so that I can continue merging stuff from people while some of the gcc-12 fallout gets sorted out. In particular, gcc-12 is very unhappy about the kinds of pointer arithmetic tricks that netfs does, and that makes the fortify checks trigger in afs and ceph: In function ‘fortify_memset_chk’, inlined from ‘netfs_i_context_init’ at include/linux/netfs.h:327:2, inlined from ‘afs_set_netfs_context’ at fs/afs/inode.c:61:2, inlined from ‘afs_root_iget’ at fs/afs/inode.c:543:2: include/linux/fortify-string.h:258:25: warning: call to ‘__write_overflow_field’ declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning] 258 | __write_overflow_field(p_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ and the reason is that netfs_i_context_init() is passed a 'struct inode' pointer, and then it does struct netfs_i_context *ctx = netfs_i_context(inode); memset(ctx, 0, sizeof(*ctx)); where that netfs_i_context() function just does pointer arithmetic on the inode pointer, knowing that the netfs_i_context is laid out immediately after it in memory. This is all truly disgusting, since the whole "netfs_i_context is laid out immediately after it in memory" is not actually remotely true in general, but is just made to be that way for afs and ceph. See for example fs/cifs/cifsglob.h: struct cifsInodeInfo { struct { /* These must be contiguous */ struct inode vfs_inode; /* the VFS's inode record */ struct netfs_i_context netfs_ctx; /* Netfslib context */ }; [...] and realize that this is all entirely wrong, and the pointer arithmetic that netfs_i_context() is doing is also very very wrong and wouldn't give the right answer if netfs_ctx had different alignment rules from a 'struct inode', for example). Anyway, that's just a long-winded way to say "the gcc-12 warning is actually quite reasonable, and our code happens to work but is pretty disgusting". This is getting fixed properly, but for now I made the mistake of thinking "the week right after the merge window tends to be calm for me as people take a breather" and I did a sustem upgrade. And I got gcc-12 as a result, so to continue merging fixes from people and not have the end result drown in warnings, I am fixing all these gcc-12 issues I hit. Including with these kinds of temporary fixes. Cc: Kees Cook Cc: David Howells Link: https://lore.kernel.org/all/AEEBCF5D-8402-441D-940B-105AA718C71F@chromium.org/ Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/afs/inode.c | 3 +++ fs/ceph/inode.c | 3 +++ 2 files changed, 6 insertions(+) diff --git a/fs/afs/inode.c b/fs/afs/inode.c index 30b066299d39..65b439cd53d2 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -25,6 +25,9 @@ #include "internal.h" #include "afs_fs.h" +// Temporary: netfs does disgusting things with inode pointers +#pragma GCC diagnostic ignored "-Wattribute-warning" + static const struct inode_operations afs_symlink_inode_operations = { .get_link = page_get_link, }; diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index 63113e2a4890..83739dae5268 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -20,6 +20,9 @@ #include "cache.h" #include +// Temporary: netfs does disgusting things with inode pointers +#pragma GCC diagnostic ignored "-Wattribute-warning" + /* * Ceph inode operations * -- 2.35.1