Re: [PATCH] usb: cdns3: gadget: fix resource leak on gadget init failure
From: Peter Chen (CIX)
Date: Mon Mar 30 2026 - 01:56:48 EST
On 26-03-28 23:15:50, Yongchao Wu wrote:
> When cdns3_gadget_start() fails, the DRD gadget is left in an
> initialized state, causing a resource leak. When switching to host
> mode, the stale state triggers a synchronous external abort in
> xhci_gen_setup(), leading to kernel panic:
>
> [ 1301.377716][ T5000][E] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP
> [ 1301.382485][ T5000][I] pc : xhci_gen_setup+0xa4/0x408
> [ 1301.393391][ T5000][I] backtrace:
> ...
> xhci_gen_setup+0xa4/0x408 <-- CRASH
> xhci_plat_setup+0x44/0x58
> usb_add_hcd+0x284/0x678
> ...
> cdns_role_set+0x9c/0xbc <-- Role switch
>
> Fix by calling cdns_drd_gadget_off() in the error path to properly
> clean up the DRD gadget state. This prevents both the resource leak
> and the kernel panic during role switching.
>
Good catch.
I have two questions:
- What exactly resource is leaked?
- Do you call cdns_drd_host_on before setup host?
Besides, you may add Fixed-by tag and Cc to stable tree.
Peter
> Signed-off-by: Yongchao Wu <yongchao.wu@xxxxxxxxxxxxx>
> ---
> drivers/usb/cdns3/cdns3-gadget.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
> index d59a60a16..4cc3f2ffb 100644
> --- a/drivers/usb/cdns3/cdns3-gadget.c
> +++ b/drivers/usb/cdns3/cdns3-gadget.c
> @@ -3428,6 +3428,7 @@ static int __cdns3_gadget_init(struct cdns *cdns)
> ret = cdns3_gadget_start(cdns);
> if (ret) {
> pm_runtime_put_sync(cdns->dev);
> + cdns_drd_gadget_off(cdns);
> return ret;
> }
>
> --
> 2.43.0
>
>
--
Best regards,
Peter