From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752677AbdIIXAY (ORCPT ); Sat, 9 Sep 2017 19:00:24 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43076 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751792AbdIIXAV (ORCPT ); Sat, 9 Sep 2017 19:00:21 -0400 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, "Oleg Drokin" , "Andreas Dilger" , "Greg Kroah-Hartman" , "John L. Hammond" , "Li Wei" Date: Sat, 09 Sep 2017 22:47:14 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 113/233] staging/lustre/lov: remove set_fs() call from lov_getstripe() In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.48-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Drokin commit 0a33252e060e97ed3fbdcec9517672f1e91aaef3 upstream. lov_getstripe() calls set_fs(KERNEL_DS) so that it can handle a struct lov_user_md pointer from user- or kernel-space. This changes the behavior of copy_from_user() on SPARC and may result in a misaligned access exception which in turn oopses the kernel. In fact the relevant argument to lov_getstripe() is never called with a kernel-space pointer and so changing the address limits is unnecessary and so we remove the calls to save, set, and restore the address limits. Signed-off-by: John L. Hammond Reviewed-on: http://review.whamcloud.com/6150 Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3221 Reviewed-by: Andreas Dilger Reviewed-by: Li Wei Signed-off-by: Oleg Drokin Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/staging/lustre/lustre/lov/lov_pack.c | 9 --------- 1 file changed, 9 deletions(-) --- a/drivers/staging/lustre/lustre/lov/lov_pack.c +++ b/drivers/staging/lustre/lustre/lov/lov_pack.c @@ -592,18 +592,10 @@ int lov_getstripe(struct obd_export *exp struct lov_mds_md *lmmk = NULL; int rc, lmm_size; int lum_size; - mm_segment_t seg; if (!lsm) return -ENODATA; - /* - * "Switch to kernel segment" to allow copying from kernel space by - * copy_{to,from}_user(). - */ - seg = get_fs(); - set_fs(KERNEL_DS); - /* we only need the header part from user space to get lmm_magic and * lmm_stripe_count, (the header part is common to v1 and v3) */ lum_size = sizeof(struct lov_user_md_v1); @@ -672,6 +664,5 @@ int lov_getstripe(struct obd_export *exp obd_free_diskmd(exp, &lmmk); out_set: - set_fs(seg); return rc; }