Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41094 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932345AbeCWKHG (ORCPT ); Fri, 23 Mar 2018 06:07:06 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust , Sasha Levin Subject: [PATCH 4.9 069/177] pNFS: Fix use after free issues in pnfs_do_read() Date: Fri, 23 Mar 2018 10:53:17 +0100 Message-Id: <20180323094208.373666529@linuxfoundation.org> In-Reply-To: <20180323094205.090519271@linuxfoundation.org> References: <20180323094205.090519271@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Trond Myklebust [ Upstream commit 6aeafd05eca9bc8ab6b03d7e56d09ffd18190f44 ] The assumption should be that if the caller returns PNFS_ATTEMPTED, then hdr has been consumed, and so we should not be testing hdr->task.tk_status. If the caller returns PNFS_TRY_AGAIN, then we need to recoalesce and free hdr. Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/nfs/pnfs.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -2308,10 +2308,20 @@ pnfs_do_read(struct nfs_pageio_descripto enum pnfs_try_status trypnfs; trypnfs = pnfs_try_to_read_data(hdr, call_ops, lseg); - if (trypnfs == PNFS_TRY_AGAIN) - pnfs_read_resend_pnfs(hdr); - if (trypnfs == PNFS_NOT_ATTEMPTED || hdr->task.tk_status) + switch (trypnfs) { + case PNFS_NOT_ATTEMPTED: pnfs_read_through_mds(desc, hdr); + case PNFS_ATTEMPTED: + break; + case PNFS_TRY_AGAIN: + /* cleanup hdr and prepare to redo pnfs */ + if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) { + struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); + list_splice_init(&hdr->pages, &mirror->pg_list); + mirror->pg_recoalesce = 1; + } + hdr->mds_ops->rpc_release(hdr); + } } static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)