On Wed, Apr 17, 2019 at 05:05:33PM +0000, zhuyan (M) wrote: > On Wed, 17 Apr 2019, Alan Stern wrote: > > > On Wed, 17 Apr 2019, zhuyan (M) wrote: > > > > > On Tue, 16 Apr 2019 11:07:56 -0400, Alan Stern wrote: > > > > > > > On Tue, 16 Apr 2019, zhuyan (M) wrote: > > > > > On Tue, 16 Apr 2019 at 11:45:45 +0200, Greg KH wrote: > > > > > > On Tue, Apr 09, 2019 at 10:37:12PM +0800, zhuyan wrote: > > > > > > > In function fhci_queue_urb, the divisor of expression > > > > > > > (urb->transfer_buffer_length % usb_maxpacket(urb->dev, > > > > > > > urb->pipe, > > > > > > > usb_pipeout(urb->pipe))) may be zero. > > > > > > > > > > > > How can you hit that? > > > > > > > > > > > > > When it is zero, unexpected results may occur, so it is > > > > > > > necessary to ensure that the divisor is not zero. > > > > > > > > > > > > > > Signed-off-by: zhuyan <zhuyan34@xxxxxxxxxx> > > > > > > > > > > > > I need a "Full" name here, not just a single name. Whatever you use to sign documents is good. > > > > > > > > > > > > thanks, > > > > > > > > > > > > greg k-h > > > > > > > > > > In function usb_maxpacket, when ep is NULL, its return value is 0. > > > > > > > > fhci_queue_urb() shouldn't use urb->pipe to compute the maxpacket > > > > size anyway. It should use usb_endpoint_maxp(&urb->ep->desc). > > > > > > Currently, fhci_queue_urb(), call usb_maxpacket() multiple times to > > > calculate the maxpacket size. The usb_maxpacket() will call > > > usb_endpoint_maxp() to compute the maxpacket size. > > > > I know that. What fhci_queue_urb() is doing is wrong. You should change it: > > Make it call usb_endpoint_maxp directly instead of calling usb_maxpacket. > > > > >From 1996456d0cc17b5ff7746a598ff355b25d13db3e Mon Sep 17 00:00:00 2001 > From: zhuyan <zhuyan34@xxxxxxxxxx> > Date: Thu, 18 Apr 2019 00:53:03 +0800 > Subject: [PATCH] usb: host: fix divide-by-zero in function fhci_queue_urb > > fhci_queue_urb() shouldn't use urb->pipe to compute the maxpacket > size anyway.It should use usb_endpoint_maxp(&urb->ep->desc). > > In function fhci_queue_urb, the divisor of expression > (urb->transfer_buffer_length % usb_maxpacket(urb->dev, urb->pipe, > usb_pipeout(urb->pipe))) may be zero. When it is zero, unexpected results > may occur, so it is necessary to ensure that the divisor is not zero. > > Signed-off-by: zhuyan <zhuyan34@xxxxxxxxxx> I still need a full name here and on the From: line :( thanks, greg k-h
