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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 1D92CC71122 for ; Sun, 14 Oct 2018 15:57:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6CAE2077C for ; Sun, 14 Oct 2018 15:57:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6CAE2077C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729795AbeJNXib (ORCPT ); Sun, 14 Oct 2018 19:38:31 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:37576 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727563AbeJNXia (ORCPT ); Sun, 14 Oct 2018 19:38:30 -0400 Received: from [2a02:8011:400e:2:cbab:f00:c93f:614] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1gBiM0-0004cp-KR; Sun, 14 Oct 2018 16:30:52 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gBiLT-0000Mz-Eh; Sun, 14 Oct 2018 16:30:19 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jan Kara" , "Theodore Ts'o" , "Andreas Dilger" Date: Sun, 14 Oct 2018 16:25:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 169/366] ext4: set h_journal if there is a failure starting a reserved handle In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:cbab:f00:c93f:614 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit b2569260d55228b617bd82aba6d0db2faeeb4116 upstream. If ext4 tries to start a reserved handle via jbd2_journal_start_reserved(), and the journal has been aborted, this can result in a NULL pointer dereference. This is because the fields h_journal and h_transaction in the handle structure share the same memory, via a union, so jbd2_journal_start_reserved() will clear h_journal before calling start_this_handle(). If this function fails due to an aborted handle, h_journal will still be NULL, and the call to jbd2_journal_free_reserved() will pass a NULL journal to sub_reserve_credits(). This can be reproduced by running "kvm-xfstests -c dioread_nolock generic/475". Fixes: 8f7d89f36829b ("jbd2: transaction reservation support") Signed-off-by: Theodore Ts'o Reviewed-by: Andreas Dilger Reviewed-by: Jan Kara Signed-off-by: Ben Hutchings --- fs/jbd2/transaction.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -515,6 +515,7 @@ int jbd2_journal_start_reserved(handle_t */ ret = start_this_handle(journal, handle, GFP_NOFS); if (ret < 0) { + handle->h_journal = journal; jbd2_journal_free_reserved(handle); return ret; }