Path: csiph.com!aioe.org!bofh.it!news.nic.it!robomod From: Oleg Drokin Newsgroups: linux.kernel Subject: [PATCH] staging/lustre/lov: remove set_fs() call from lov_getstripe() Date: Sat, 27 May 2017 07:20:01 +0200 Message-ID: X-Greylist: delayed 3597 seconds by postgrey-1.27 at vger.kernel.org; Sat, 27 May 2017 01:13:27 EDT X-Mailer: git-send-email 2.9.3 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 51 Organization: linux.* mail to news gateway X-Original-Cc: Linux Kernel Mailing List , Lustre Development List , Oleg Drokin , "John L . Hammond" X-Original-Date: Fri, 26 May 2017 23:40:33 -0400 X-Original-Message-ID: <20170527034033.223677-1-green@linuxhacker.ru> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1651758 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 --- drivers/staging/lustre/lustre/lov/lov_pack.c | 9 --------- 1 file changed, 9 deletions(-) diff --git a/drivers/staging/lustre/lustre/lov/lov_pack.c b/drivers/staging/lustre/lustre/lov/lov_pack.c index 2e1bd47..e6727ce 100644 --- a/drivers/staging/lustre/lustre/lov/lov_pack.c +++ b/drivers/staging/lustre/lustre/lov/lov_pack.c @@ -293,18 +293,10 @@ int lov_getstripe(struct lov_object *obj, struct lov_stripe_md *lsm, size_t lmmk_size; size_t lum_size; int rc; - 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); - if (lsm->lsm_magic != LOV_MAGIC_V1 && lsm->lsm_magic != LOV_MAGIC_V3) { CERROR("bad LSM MAGIC: 0x%08X != 0x%08X nor 0x%08X\n", lsm->lsm_magic, LOV_MAGIC_V1, LOV_MAGIC_V3); @@ -406,6 +398,5 @@ int lov_getstripe(struct lov_object *obj, struct lov_stripe_md *lsm, out_free: kvfree(lmmk); out: - set_fs(seg); return rc; } -- 2.9.3