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Message-ID: <20210511163907.GB901897@rowland.harvard.edu>
Date: Tue, 11 May 2021 12:39:07 -0400
From: Alan Stern <stern@...land.harvard.edu>
To: Chunfeng Yun <chunfeng.yun@...iatek.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
"Gustavo A . R . Silva" <gustavoars@...nel.org>,
Bixuan Cui <cuibixuan@...wei.com>,
Eugeniu Rosca <erosca@...adit-jv.com>,
Oliver Neukum <oneukum@...e.com>, linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org,
Tianping Fang <tianping.fang@...iatek.com>,
Eddie Hung <eddie.hung@...iatek.com>,
Ikjoon Jang <ikjn@...omium.org>
Subject: Re: [PATCH] usb: core: hub: fix race condition about TRSMRCY of
resume
On Tue, May 11, 2021 at 06:15:22PM +0800, Chunfeng Yun wrote:
> This may happen if the port becomes resume status exactly
> when usb_port_resume() gets port status, it still need provide
> a TRSMCRY time before access the device.
>
> Reported-by: Tianping Fang <tianping.fang@...iatek.com>
> Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
This should also say:
CC: <stable@...r.kernel.org>
> ---
> drivers/usb/core/hub.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index b2bc4b7c4289..fc7d6cdacf16 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -3642,9 +3642,6 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
> * sequence.
> */
> status = hub_port_status(hub, port1, &portstatus, &portchange);
> -
> - /* TRSMRCY = 10 msec */
> - msleep(10);
> }
>
> SuspendCleared:
> @@ -3659,6 +3656,9 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
> usb_clear_port_feature(hub->hdev, port1,
> USB_PORT_FEAT_C_SUSPEND);
> }
> +
> + /* TRSMRCY = 10 msec */
> + msleep(10);
> }
>
> if (udev->persist_enabled)
Acked-by: Alan Stern <stern@...land.harvard.edu>
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