diff mbox series

[v2,2/2] usb: dwc3: Prevent cleanup cancelled requests at the same time.

Message ID 1644836933-141376-3-git-send-email-dh10.jung@samsung.com
State New
Headers show
Series Fix ep command fail issue in dequeue | expand

Commit Message

Jung Daehwan Feb. 14, 2022, 11:08 a.m. UTC 
We added cleanup cancelled requests when ep cmd timeout on ep dequeue
because there's no complete interrupt then. But, we find out new case
that complete interrupt comes up later. list_for_each_entry_safe is
used when cleanup cancelled requests and it has vulnerabilty on multi-core
environment. dwc3_gadget_giveback unlocks dwc->lock temporarily and other
core(ISR) can get lock and try to cleanup them again. It could cause
list_del corruption and we use DWC3_EP_END_TRANSFER_PENDING to prevent it.

1. MTP server cancels -> ep dequeue -> ep cmd timeout(END_TRANSFER)
	-> cleanup cancelled requests -> dwc3_gadget_giveback ->
	list_del -> release lock temporarily
2. Complete with END_TRANSFER -> ISR(dwc3_gadget_endpoint_command_complete)
	gets lock -> cleanup cancelled requests -> dwc3_gadget_giveback
	-> list_del
3. MTP server process gets lock again
	-> tries to access POISON list(list_del corruption)

[2: MtpServer: 5032] dwc3 10b00000.dwc3: request cancelled
						with wrong reason:5
[2: MtpServer: 5032] list_del corruption,
		ffffff88b6963968->next is LIST_POISON1 (dead000000000100)

Signed-off-by: Daehwan Jung <dh10.jung@samsung.com>
---
 drivers/usb/dwc3/gadget.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 3ad3bc5813ca..bac3814894e2 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2046,8 +2046,11 @@  static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
 
 			/* If ep cmd fails, then force to giveback cancelled requests here */
 			if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING)) {
-				dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
+				dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
 				dwc3_gadget_ep_cleanup_cancelled_requests(dep);
+
+				dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
+				dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
 			}
 
 			dep->flags &= ~DWC3_EP_WAIT_TRANSFER_COMPLETE;
@@ -3426,9 +3429,11 @@  static void dwc3_gadget_endpoint_command_complete(struct dwc3_ep *dep,
 	if (dep->stream_capable)
 		dep->flags |= DWC3_EP_IGNORE_NEXT_NOSTREAM;
 
+	if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING))
+		dwc3_gadget_ep_cleanup_cancelled_requests(dep);
+
 	dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
 	dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
-	dwc3_gadget_ep_cleanup_cancelled_requests(dep);
 
 	if (dep->flags & DWC3_EP_PENDING_CLEAR_STALL) {
 		struct dwc3 *dwc = dep->dwc;