On Thu, May 12, 2022 at 12:37:39PM +0800, Albert Wang wrote:
> After inspecting further, we do see the locking is implicit, with the
> main gotcha being the unlock/re-lock. That creates a window for a race
> to happen. This change moves the NULL check to be adjacent to where
> to it's used and after the window is "closed".
>
> Fixes: 26288448120b ("usb: dwc3: gadget: Fix null pointer exception")
>
> Signed-off-by: Albert Wang <albertccwang@xxxxxxxxxx>
> ---
> drivers/usb/dwc3/gadget.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 19477f4bbf54..fda58951cf27 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -3366,14 +3366,19 @@ static bool dwc3_gadget_endpoint_trbs_complete(struct dwc3_ep *dep,
> struct dwc3 *dwc = dep->dwc;
> bool no_started_trb = true;
>
> - if (!dep->endpoint.desc)
> - return no_started_trb;
> -
> + /*
> + * This function eventually leads to dwc3_giveback() which unlocks
> + * the dwc->lock and relocks afterwards. This actually creates a
> + * a window for a race to happen.
> + */
> dwc3_gadget_ep_cleanup_completed_requests(dep, event, status);
>
> if (dep->flags & DWC3_EP_END_TRANSFER_PENDING)
> goto out;
>
> + if (!dep->endpoint.desc)
> + return no_started_trb;
> +
> if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
> list_empty(&dep->started_list) &&
> (list_empty(&dep->pending_list) || status == -EXDEV))
> --
> 2.36.0.550.gb090851708-goog
>
Hi,
This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
a patch that has triggered this response. He used to manually respond
to these common problems, but in order to save his sanity (he kept
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