xfs: fix unaligned access in xfs_btree_visit_blocks

sandeen · gregkh · commit c56605c69ba6 · 2017-06-07T12:06:03.000+02:00
commit a4d768e702de224cc85e0c8eac9311763403b368 upstream.

This structure copy was throwing unaligned access warnings on sparc64:

Kernel unaligned access at TPC[1043c088] xfs_btree_visit_blocks+0x88/0xe0 [xfs]

xfs_btree_copy_ptrs does a memcpy, which avoids it.

Signed-off-by: Eric Sandeen &lt;sandeen@redhat.com&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
@@ -4064,7 +4064,7 @@ xfs_btree_change_owner(
 			xfs_btree_readahead_ptr(cur, ptr, 1);
 
 			/* save for the next iteration of the loop */
-			lptr = *ptr;
+			xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);
 		}
 
 		/* for each buffer in the level */

Original file line number	Diff line number	Diff line change
`@@ -4064,7 +4064,7 @@ xfs_btree_change_owner(`
`4064`	`4064`	`xfs_btree_readahead_ptr(cur, ptr, 1);`
`4065`	`4065`
`4066`	`4066`	`/* save for the next iteration of the loop */`
`4067`		`- lptr = *ptr;`
	`4067`	`+ xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);`
`4068`	`4068`	`}`
`4069`	`4069`
`4070`	`4070`	`/* for each buffer in the level */`