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 3FC1CEE4980 for ; Fri, 18 Aug 2023 17:36:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379101AbjHRRgC (ORCPT ); Fri, 18 Aug 2023 13:36:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379123AbjHRRfu (ORCPT ); Fri, 18 Aug 2023 13:35:50 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C07973C2F; Fri, 18 Aug 2023 10:35:47 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 55CF46305E; Fri, 18 Aug 2023 17:35:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D657C433C7; Fri, 18 Aug 2023 17:35:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1692380146; bh=ZxyRx6vw13rnn3oOcM2o1IWE3zEVmVLRQvTn/TvtJHg=; h=Date:To:From:Subject:From; b=GpinnRsa1Cd2ssDLVIgRKkL9iuzX6cI6ze/hL64S7IRsINiUi7DuyU3h01SBaRCUg 6E0+SdcVxCJoaKnq/q3O6Uy4EkhyrO0AEOUbYtytQUWQcKMzVx+5I36ZKfg8Ds5A7i hQuee6e5BtWBarXisIJYp1AIbrDAiJG2pum8CerM= Date: Fri, 18 Aug 2023 10:35:45 -0700 To: mm-commits@vger.kernel.org, stable@vger.kernel.org, konishi.ryusuke@gmail.com, akpm@linux-foundation.org From: Andrew Morton Subject: + nilfs2-fix-warning-in-mark_buffer_dirty-due-to-discarded-buffer-reuse.patch added to mm-hotfixes-unstable branch Message-Id: <20230818173546.9D657C433C7@smtp.kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-fix-warning-in-mark_buffer_dirty-due-to-discarded-buffer-reuse.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nilfs2-fix-warning-in-mark_buffer_dirty-due-to-discarded-buffer-reuse.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Ryusuke Konishi Subject: nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse Date: Fri, 18 Aug 2023 22:18:04 +0900 A syzbot stress test using a corrupted disk image reported that mark_buffer_dirty() called from __nilfs_mark_inode_dirty() or nilfs_palloc_commit_alloc_entry() may output a kernel warning, and can panic if the kernel is booted with panic_on_warn. This is because nilfs2 keeps buffer pointers in local structures for some metadata and reuses them, but such buffers may be forcibly discarded by nilfs_clear_dirty_page() in some critical situations. This issue is reported to appear after commit 28a65b49eb53 ("nilfs2: do not write dirty data after degenerating to read-only"), but the issue has potentially existed before. Fix this issue by checking the uptodate flag when attempting to reuse an internally held buffer, and reloading the metadata instead of reusing the buffer if the flag was lost. Link: https://lkml.kernel.org/r/20230818131804.7758-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi Reported-by: syzbot+cdfcae656bac88ba0e2d@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/0000000000003da75f05fdeffd12@google.com Fixes: 8c26c4e2694a ("nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption") Tested-by: Ryusuke Konishi Cc: # 3.10+ Signed-off-by: Andrew Morton --- fs/nilfs2/alloc.c | 3 ++- fs/nilfs2/inode.c | 7 +++++-- 2 files changed, 7 insertions(+), 3 deletions(-) --- a/fs/nilfs2/alloc.c~nilfs2-fix-warning-in-mark_buffer_dirty-due-to-discarded-buffer-reuse +++ a/fs/nilfs2/alloc.c @@ -205,7 +205,8 @@ static int nilfs_palloc_get_block(struct int ret; spin_lock(lock); - if (prev->bh && blkoff == prev->blkoff) { + if (prev->bh && blkoff == prev->blkoff && + likely(buffer_uptodate(prev->bh))) { get_bh(prev->bh); *bhp = prev->bh; spin_unlock(lock); --- a/fs/nilfs2/inode.c~nilfs2-fix-warning-in-mark_buffer_dirty-due-to-discarded-buffer-reuse +++ a/fs/nilfs2/inode.c @@ -1025,7 +1025,7 @@ int nilfs_load_inode_block(struct inode int err; spin_lock(&nilfs->ns_inode_lock); - if (ii->i_bh == NULL) { + if (ii->i_bh == NULL || unlikely(!buffer_uptodate(ii->i_bh))) { spin_unlock(&nilfs->ns_inode_lock); err = nilfs_ifile_get_inode_block(ii->i_root->ifile, inode->i_ino, pbh); @@ -1034,7 +1034,10 @@ int nilfs_load_inode_block(struct inode spin_lock(&nilfs->ns_inode_lock); if (ii->i_bh == NULL) ii->i_bh = *pbh; - else { + else if (unlikely(!buffer_uptodate(ii->i_bh))) { + __brelse(ii->i_bh); + ii->i_bh = *pbh; + } else { brelse(*pbh); *pbh = ii->i_bh; } _ Patches currently in -mm which might be from konishi.ryusuke@gmail.com are nilfs2-fix-general-protection-fault-in-nilfs_lookup_dirty_data_buffers.patch nilfs2-fix-warning-in-mark_buffer_dirty-due-to-discarded-buffer-reuse.patch