From patchwork Tue Feb 18 19:55:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 231157 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E7EBC34026 for ; Tue, 18 Feb 2020 19:57:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 424E124125 for ; Tue, 18 Feb 2020 19:57:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582055853; bh=Hh3IRsjLUN15zrgEekw5SRbopEXDRppNaLMd24qGHP4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=15QlzcwWKC7/Idl+1c5WbzmHJLJXbRl707qKwK0pxfJMJxUwqjMUabDP6GupdiI45 aQHJY0RyG6KcQCj0ClNVyjLxT+b2HmMgor1u0GNQFOaS6Ys5EGvq/22ejsDuQR3b1a Rljz6gxLfGVY5n3rbK5AELC+GhoNMA3vMuw9a0ks= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726801AbgBRT5c (ORCPT ); Tue, 18 Feb 2020 14:57:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:34896 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727946AbgBRT5b (ORCPT ); Tue, 18 Feb 2020 14:57:31 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CDA3520659; Tue, 18 Feb 2020 19:57:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582055851; bh=Hh3IRsjLUN15zrgEekw5SRbopEXDRppNaLMd24qGHP4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kT29eLHEau+HRjWl/Y5ut8fHLa5OvXclV+RhRi0fFmxCtKRvRbqntg3D46+vaoBdn 6mGkEBA9bMJbpr3zvvXBf5irtDkm1fbNxY9QBImJSeD3vAoAtZJZ1ND0p7yf14iTZo +Yi/8JrU+G7LbnA4ztuGbmbQod0ZtV02I8BKNd1Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , "zhangyi (F)" , Theodore Tso , stable@kernel.org, Sasha Levin Subject: [PATCH 4.19 37/38] jbd2: do not clear the BH_Mapped flag when forgetting a metadata buffer Date: Tue, 18 Feb 2020 20:55:23 +0100 Message-Id: <20200218190422.815937101@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200218190418.536430858@linuxfoundation.org> References: <20200218190418.536430858@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: zhangyi (F) [ Upstream commit c96dceeabf765d0b1b1f29c3bf50a5c01315b820 ] Commit 904cdbd41d74 ("jbd2: clear dirty flag when revoking a buffer from an older transaction") set the BH_Freed flag when forgetting a metadata buffer which belongs to the committing transaction, it indicate the committing process clear dirty bits when it is done with the buffer. But it also clear the BH_Mapped flag at the same time, which may trigger below NULL pointer oops when block_size < PAGE_SIZE. rmdir 1 kjournald2 mkdir 2 jbd2_journal_commit_transaction commit transaction N jbd2_journal_forget set_buffer_freed(bh1) jbd2_journal_commit_transaction commit transaction N+1 ... clear_buffer_mapped(bh1) ext4_getblk(bh2 ummapped) ... grow_dev_page init_page_buffers bh1->b_private=NULL bh2->b_private=NULL jbd2_journal_put_journal_head(jh1) __journal_remove_journal_head(hb1) jh1 is NULL and trigger oops *) Dir entry block bh1 and bh2 belongs to one page, and the bh2 has already been unmapped. For the metadata buffer we forgetting, we should always keep the mapped flag and clear the dirty flags is enough, so this patch pick out the these buffers and keep their BH_Mapped flag. Link: https://lore.kernel.org/r/20200213063821.30455-3-yi.zhang@huawei.com Fixes: 904cdbd41d74 ("jbd2: clear dirty flag when revoking a buffer from an older transaction") Reviewed-by: Jan Kara Signed-off-by: zhangyi (F) Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Sasha Levin --- fs/jbd2/commit.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 3fe9b7c27ce82..c321fa06081ce 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -980,12 +980,29 @@ void jbd2_journal_commit_transaction(journal_t *journal) * pagesize and it is attached to the last partial page. */ if (buffer_freed(bh) && !jh->b_next_transaction) { + struct address_space *mapping; + clear_buffer_freed(bh); clear_buffer_jbddirty(bh); - clear_buffer_mapped(bh); - clear_buffer_new(bh); - clear_buffer_req(bh); - bh->b_bdev = NULL; + + /* + * Block device buffers need to stay mapped all the + * time, so it is enough to clear buffer_jbddirty and + * buffer_freed bits. For the file mapping buffers (i.e. + * journalled data) we need to unmap buffer and clear + * more bits. We also need to be careful about the check + * because the data page mapping can get cleared under + * out hands, which alse need not to clear more bits + * because the page and buffers will be freed and can + * never be reused once we are done with them. + */ + mapping = READ_ONCE(bh->b_page->mapping); + if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) { + clear_buffer_mapped(bh); + clear_buffer_new(bh); + clear_buffer_req(bh); + bh->b_bdev = NULL; + } } if (buffer_jbddirty(bh)) {