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@xxxxxxxxxxx>
---
drivers/usb/dwc3/gadget.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
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;
--
2.31.1
