diff options
| author | Manish Nagar <manish.nagar@oss.qualcomm.com> | 2025-11-20 13:14:35 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-11-21 15:15:48 +0100 |
| commit | e4037689a366743c4233966f0e74bc455820d316 (patch) | |
| tree | 2a004d13a5868337e6849a2814464db671869471 | |
| parent | 1f73b8b56cf35de29a433aee7bfff26cea98be3f (diff) | |
usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths
This patch addresses a race condition caused by unsynchronized
execution of multiple call paths invoking `dwc3_remove_requests()`,
leading to premature freeing of USB requests and subsequent crashes.
Three distinct execution paths interact with `dwc3_remove_requests()`:
Path 1:
Triggered via `dwc3_gadget_reset_interrupt()` during USB reset
handling. The call stack includes:
- `dwc3_ep0_reset_state()`
- `dwc3_ep0_stall_and_restart()`
- `dwc3_ep0_out_start()`
- `dwc3_remove_requests()`
- `dwc3_gadget_del_and_unmap_request()`
Path 2:
Also initiated from `dwc3_gadget_reset_interrupt()`, but through
`dwc3_stop_active_transfers()`. The call stack includes:
- `dwc3_stop_active_transfers()`
- `dwc3_remove_requests()`
- `dwc3_gadget_del_and_unmap_request()`
Path 3:
Occurs independently during `adb root` execution, which triggers
USB function unbind and bind operations. The sequence includes:
- `gserial_disconnect()`
- `usb_ep_disable()`
- `dwc3_gadget_ep_disable()`
- `dwc3_remove_requests()` with `-ESHUTDOWN` status
Path 3 operates asynchronously and lacks synchronization with Paths
1 and 2. When Path 3 completes, it disables endpoints and frees 'out'
requests. If Paths 1 or 2 are still processing these requests,
accessing freed memory leads to a crash due to use-after-free conditions.
To fix this added check for request completion and skip processing
if already completed and added the request status for ep0 while queue.
Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
Cc: stable <stable@kernel.org>
Suggested-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Manish Nagar <manish.nagar@oss.qualcomm.com>
Link: https://patch.msgid.link/20251120074435.1983091-1-manish.nagar@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/dwc3/ep0.c | 1 | ||||
| -rw-r--r-- | drivers/usb/dwc3/gadget.c | 7 |
2 files changed, 8 insertions, 0 deletions
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index b4229aa13f37..e0bad5708664 100644 --- a/drivers/usb/dwc3/ep0.c +++ b/drivers/usb/dwc3/ep0.c @@ -94,6 +94,7 @@ static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep, req->request.actual = 0; req->request.status = -EINPROGRESS; req->epnum = dep->number; + req->status = DWC3_REQUEST_STATUS_QUEUED; list_add_tail(&req->list, &dep->pending_list); diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 6f18b4840a25..5e4997f974dd 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -228,6 +228,13 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req, { struct dwc3 *dwc = dep->dwc; + /* + * The request might have been processed and completed while the + * spinlock was released. Skip processing if already completed. + */ + if (req->status == DWC3_REQUEST_STATUS_COMPLETED) + return; + dwc3_gadget_del_and_unmap_request(dep, req, status); req->status = DWC3_REQUEST_STATUS_COMPLETED; |