usb: fix for parallel transfer deadlock with usb_transfer_sync() (22c0d015) · Commits · Wenxi XU / zephyr

Parallel transfer to same endpoint is not supported and may cause a deadlock. Adding a check to prevent starting the transfer if tranfer is already ongoing on same endpoint. Transfer status was not checked when accessing to transfer from endpoint callback. Adding status check, to prevent a double completion. Fixes #30736 Signed-off-by:

Kari Hulkko <kari.m.hulkko@gmail.com>

subsys/usb/usb_transfer.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -49,7 +49,7 @@ static struct usb_transfer_data ut_data[CONFIG_USB_MAX_NUM_TRANSFERS];
		static struct usb_transfer_data *usb_ep_get_transfer(uint8_t ep)
		{
		for (int i = 0; i < ARRAY_SIZE(ut_data); i++) {
		if (ut_data[i].ep == ep) {
		if (ut_data[i].ep == ep && ut_data[i].status != 0) {
		return &ut_data[i];
		}
		}
		@@ -198,6 +198,11 @@ int usb_transfer(uint8_t ep, uint8_t *data, size_t dlen, unsigned int flags,
		struct usb_transfer_data *trans = NULL;
		int i, key, ret = 0;

		/* Parallel transfer to same endpoint is not supported. */
		if (usb_transfer_is_busy(ep)) {
		return -EBUSY;
		}

		LOG_DBG("Transfer start, ep 0x%02x, data %p, dlen %zd",
		ep, data, dlen);

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