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staging/lustre/lov: remove set_fs() call from lov_getstripe()

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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 <john.hammond@intel.com>
Reviewed-on: http://review.whamcloud.com/6150
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3221
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Li Wei <wei.g.li@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Oleg Drokin 2017-05-26 23:40:33 -04:00 committed by Greg Kroah-Hartman
parent 5404b0c0ea
commit c5a8004434
1 changed files with 0 additions and 9 deletions
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9
drivers/staging/lustre/lustre/lov/lov_pack.c
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@ -387,18 +387,10 @@ int lov_getstripe(struct lov_object *obj, struct lov_stripe_md *lsm,
struct lov_mds_md *lmmk = NULL;
int rc, lmmk_size, 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)
*/
@ -478,6 +470,5 @@ int lov_getstripe(struct lov_object *obj, struct lov_stripe_md *lsm,
out_free:
kfree(lmmk);
out:
set_fs(seg);
return rc;
}