Messages in this thread Patch in this message | | | From | Yoshihiro Shimoda <> | Subject | RE: [PATCH] usb: gadget: udc: renesas_usb3: Fix use after free bug in renesas_usb3_remove due to race condition | Date | Fri, 10 Mar 2023 04:56:31 +0000 |
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Hi Zheng,
> From: Zheng Wang, Sent: Friday, March 10, 2023 4:30 AM > > In renesas_usb3_probe, &usb3->role_work is bound with > renesas_usb3_role_work. renesas_usb3_start will be called > to start the work. > > If we remove the module which will call renesas_usb3_remove > to make cleanup, there may be a unfinished work. The possible > sequence is as follows:
Thank you for the patch! I think we should remove double spaces like below. (Also "an" unfinished):
----- If we remove the module which will call renesas_usb3_remove to make cleanup, there may be an unfinished work. The possible sequence is as follows: -----
> Fix it by canceling the work before cleanup in the renesas_usb3_remove > > CPU0 CPUc1
s/CPUc1/CPU1/
> |renesas_usb3_role_work > renesas_usb3_remove | > usb_role_switch_unregister | > device_unregister | > kfree(sw); | > free usb3->role_sw | > | usb_role_switch_set_role > | //use usb3->role_sw
Adding a blank line here is better, I think.
> Fixes: 39facfa01c9f ("usb: gadget: udc: renesas_usb3: Add register of usb role switch") > Signed-off-by: Zheng Wang <zyytlz.wz@163.com> > --- > drivers/usb/gadget/udc/renesas_usb3.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c > index bee6bceafc4f..23b5f1706d25 100644 > --- a/drivers/usb/gadget/udc/renesas_usb3.c > +++ b/drivers/usb/gadget/udc/renesas_usb3.c > @@ -2658,6 +2658,8 @@ static int renesas_usb3_remove(struct platform_device *pdev) > { > struct renesas_usb3 *usb3 = platform_get_drvdata(pdev); > > + cancel_work_sync(&usb3->extcon_work);
IIUC, this work is not related to the issue. But, what do you think? If so, adding this should be a separate patch with the following Fixes tag:
Fixes: 3b68e7ca3888 ("usb: gadget: udc: renesas_usb3: add extcon support")
Best regards, Yoshihiro Shimoda
> + cancel_work_sync(&usb3->role_work); > debugfs_remove_recursive(usb3->dentry); > device_remove_file(&pdev->dev, &dev_attr_role); > > -- > 2.25.1
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