On Wed, Feb 26, 2020 at 08:01:52PM +0800, Macpaul Lin wrote: > diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c > index ce1d023..192935f 100644 > --- a/drivers/usb/gadget/function/f_fs.c > +++ b/drivers/usb/gadget/function/f_fs.c > @@ -715,7 +715,20 @@ static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req) > > static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter) > { > - ssize_t ret = copy_to_iter(data, data_len, iter); > + ssize_t ret; > + > +#if defined(CONFIG_ARM64) > + /* > + * Replace tagged address passed by user space application before > + * copying. > + */ > + if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI) && > + (iter->type == ITER_IOVEC)) { > + *(unsigned long *)&iter->iov->iov_base = > + (unsigned long)untagged_addr(iter->iov->iov_base); > + } > +#endif > + ret = copy_to_iter(data, data_len, iter); > if (likely(ret == data_len)) > return ret; I had forgotten that we discussed a similar case already a few months ago (thanks to Evgenii for pointing out). Do you have this commit applied to your tree: df325e05a682 ("arm64: Validate tagged addresses in access_ok() called from kernel threads")? -- Catalin