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Commit c5a80044 authored by Oleg Drokin's avatar Oleg Drokin Committed by Greg Kroah-Hartman
Browse files

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: default avatarJohn 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: default avatarAndreas Dilger <andreas.dilger@intel.com>
Reviewed-by: default avatarLi Wei <wei.g.li@intel.com>
Signed-off-by: default avatarOleg Drokin <green@linuxhacker.ru>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5404b0c0

drivers/staging/lustre/lustre/lov/lov_pack.c

+0 −9
Original line number Diff line number Diff line
@@ -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;

}