Re: [PATCH v4] usb: gadget: f_fs: try to fix AIO issue under ARM 64 bit TAGGED mode
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2020-02-28 16:48:55
Also in:
linux-mediatek, linux-usb, lkml, stable
On Wed, Feb 26, 2020 at 08:01:52PM +0800, Macpaul Lin wrote:
quoted hunk ↗ jump to hunk
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
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