4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Jiang <dave.jiang@xxxxxxxxx> commit dfb06cba8c73c0704710b2e3fbe2c35ac66a01b4 upstream. copy_to_iter_mcsafe() is passing in the is_source parameter as "false" to check_copy_size(). This is different than what copy_to_iter() does. Also, the addr parameter passed to check_copy_size() is the source so therefore we should be passing in "true" instead. Fixes: 8780356ef630 ("x86/asm/memcpy_mcsafe: Define copy_to_iter_mcsafe()") Cc: <stable@xxxxxxxxxxxxxxx> Reported-by: Fan Du <fan.du@xxxxxxxxx> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx> Reviewed-by: Vishal Verma <vishal.l.verma@xxxxxxxxx> Reported-by: Wenwei Tao <wenwei.tww@xxxxxxxxxxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/linux/uio.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -172,7 +172,7 @@ size_t copy_from_iter_flushcache(void *a static __always_inline __must_check size_t copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i) { - if (unlikely(!check_copy_size(addr, bytes, false))) + if (unlikely(!check_copy_size(addr, bytes, true))) return 0; else return _copy_to_iter_mcsafe(addr, bytes, i);