From: Oleg Drokin Date: Sat, 27 May 2017 03:40:33 +0000 (-0400) Subject: staging/lustre/lov: remove set_fs() call from lov_getstripe() X-Git-Tag: v4.11.5~70 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d9b0c955852374d6fc88e424780281623fb39c4c;p=thirdparty%2Fkernel%2Fstable.git staging/lustre/lov: remove set_fs() call from lov_getstripe() 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 --- diff --git a/drivers/staging/lustre/lustre/lov/lov_pack.c b/drivers/staging/lustre/lustre/lov/lov_pack.c index 2e1bd47337fd8..e6727cefde05b 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; }