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 B3FD91519BF; Wed, 5 Feb 2025 15:06:14 +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=1738767974; cv=none; b=Qr0u79dEAzkM6gStc4/gCjJba2EA+8Ae51azt5e2BUXDrzWIDh92hSqGCJIwM7gpUZjInQtcrYKkruCXE8Z18lys93NfQIb76c+MoT/C8137w4DUdJONjGEnzorbKMa3/5rxq+pQ5kndzlp5grIRe5eUWCOsi/USdoYxbg6OVcs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738767974; c=relaxed/simple; bh=dA4h51W+08lCLL0pW6BRulkvtGvf4SnxPZmKljxhILI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AI9h3WZUTOYxMxOzNxMilNpTVRa38iJmMCgbeP2XEh2Q7hZezS37QXYurz6cJiDQosmuSfy1UeYNHH6WcIjnW95h2tVKo3xT9MwWD+fa1NoWcydFusqxlipYPp0mKbh340GXOCmJ2gZnG+LL0bRJPEOf3av/lq2AaF4V0tNjzZQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=XU1RMEKq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="XU1RMEKq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FFDBC4CED1; Wed, 5 Feb 2025 15:06:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738767974; bh=dA4h51W+08lCLL0pW6BRulkvtGvf4SnxPZmKljxhILI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XU1RMEKqNRTugGGLhO5SHhJz9NrC3JwNom/QzqHlcnJbPUG00Xl1Qi9eI53P3gj54 QZDgaW+onVxw+D0Di4A3caDcsIROKJpkR5IUX0qLzlSayZdqEFsIm9hWxBVGbXHgPA cQlG9aKYakMgTM70VoMSEJn/klPHhBZIWuvGVTe8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ryusuke Konishi , syzbot+b2b14916b77acf8626d7@syzkaller.appspotmail.com, syzbot+d98fd19acd08b36ff422@syzkaller.appspotmail.com, Andrew Morton , Sasha Levin Subject: [PATCH 6.13 479/623] nilfs2: do not force clear folio if buffer is referenced Date: Wed, 5 Feb 2025 14:43:41 +0100 Message-ID: <20250205134514.542528872@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250205134456.221272033@linuxfoundation.org> References: <20250205134456.221272033@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ryusuke Konishi [ Upstream commit ca76bb226bf47ff04c782cacbd299f12ddee1ec1 ] Patch series "nilfs2: protect busy buffer heads from being force-cleared". This series fixes the buffer head state inconsistency issues reported by syzbot that occurs when the filesystem is corrupted and falls back to read-only, and the associated buffer head use-after-free issue. This patch (of 2): Syzbot has reported that after nilfs2 detects filesystem corruption and falls back to read-only, inconsistencies in the buffer state may occur. One of the inconsistencies is that when nilfs2 calls mark_buffer_dirty() to set a data or metadata buffer as dirty, but it detects that the buffer is not in the uptodate state: WARNING: CPU: 0 PID: 6049 at fs/buffer.c:1177 mark_buffer_dirty+0x2e5/0x520 fs/buffer.c:1177 ... Call Trace: nilfs_palloc_commit_alloc_entry+0x4b/0x160 fs/nilfs2/alloc.c:598 nilfs_ifile_create_inode+0x1dd/0x3a0 fs/nilfs2/ifile.c:73 nilfs_new_inode+0x254/0x830 fs/nilfs2/inode.c:344 nilfs_mkdir+0x10d/0x340 fs/nilfs2/namei.c:218 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257 do_mkdirat+0x264/0x3a0 fs/namei.c:4280 __do_sys_mkdirat fs/namei.c:4295 [inline] __se_sys_mkdirat fs/namei.c:4293 [inline] __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f The other is when nilfs_btree_propagate(), which propagates the dirty state to the ancestor nodes of a b-tree that point to a dirty buffer, detects that the origin buffer is not dirty, even though it should be: WARNING: CPU: 0 PID: 5245 at fs/nilfs2/btree.c:2089 nilfs_btree_propagate+0xc79/0xdf0 fs/nilfs2/btree.c:2089 ... Call Trace: nilfs_bmap_propagate+0x75/0x120 fs/nilfs2/bmap.c:345 nilfs_collect_file_data+0x4d/0xd0 fs/nilfs2/segment.c:587 nilfs_segctor_apply_buffers+0x184/0x340 fs/nilfs2/segment.c:1006 nilfs_segctor_scan_file+0x28c/0xa50 fs/nilfs2/segment.c:1045 nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1216 [inline] nilfs_segctor_collect fs/nilfs2/segment.c:1540 [inline] nilfs_segctor_do_construct+0x1c28/0x6b90 fs/nilfs2/segment.c:2115 nilfs_segctor_construct+0x181/0x6b0 fs/nilfs2/segment.c:2479 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2587 [inline] nilfs_segctor_thread+0x69e/0xe80 fs/nilfs2/segment.c:2701 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Both of these issues are caused by the callbacks that handle the page/folio write requests, forcibly clear various states, including the working state of the buffers they hold, at unexpected times when they detect read-only fallback. Fix these issues by checking if the buffer is referenced before clearing the page/folio state, and skipping the clear if it is. Link: https://lkml.kernel.org/r/20250107200202.6432-1-konishi.ryusuke@gmail.com Link: https://lkml.kernel.org/r/20250107200202.6432-2-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi Reported-by: syzbot+b2b14916b77acf8626d7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b2b14916b77acf8626d7 Reported-by: syzbot+d98fd19acd08b36ff422@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=d98fd19acd08b36ff422 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: syzbot+b2b14916b77acf8626d7@syzkaller.appspotmail.com Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- fs/nilfs2/page.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index 9de2a494a0694..899686d2e5f71 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -392,6 +392,11 @@ void nilfs_clear_dirty_pages(struct address_space *mapping) /** * nilfs_clear_folio_dirty - discard dirty folio * @folio: dirty folio that will be discarded + * + * nilfs_clear_folio_dirty() clears working states including dirty state for + * the folio and its buffers. If the folio has buffers, clear only if it is + * confirmed that none of the buffer heads are busy (none have valid + * references and none are locked). */ void nilfs_clear_folio_dirty(struct folio *folio) { @@ -399,10 +404,6 @@ void nilfs_clear_folio_dirty(struct folio *folio) BUG_ON(!folio_test_locked(folio)); - folio_clear_uptodate(folio); - folio_clear_mappedtodisk(folio); - folio_clear_checked(folio); - head = folio_buffers(folio); if (head) { const unsigned long clear_bits = @@ -410,6 +411,25 @@ void nilfs_clear_folio_dirty(struct folio *folio) BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected) | BIT(BH_Delay)); + bool busy, invalidated = false; + +recheck_buffers: + busy = false; + bh = head; + do { + if (atomic_read(&bh->b_count) | buffer_locked(bh)) { + busy = true; + break; + } + } while (bh = bh->b_this_page, bh != head); + + if (busy) { + if (invalidated) + return; + invalidate_bh_lrus(); + invalidated = true; + goto recheck_buffers; + } bh = head; do { @@ -419,6 +439,9 @@ void nilfs_clear_folio_dirty(struct folio *folio) } while (bh = bh->b_this_page, bh != head); } + folio_clear_uptodate(folio); + folio_clear_mappedtodisk(folio); + folio_clear_checked(folio); __nilfs_clear_folio_dirty(folio); } -- 2.39.5