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Subject[PATCH 3.16 113/233] staging/lustre/lov: remove set_fs() call from lov_getstripe()
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

Signed-off-by: John L. Hammond <>
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);
- set_fs(seg);
return rc;
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