Re: [linux-usb-devel] [PATCH -mm] drivers/usb/core/config.c: kzalloc(0,..)

From: Alan Stern
Date: Tue May 08 2007 - 11:57:27 EST


On Tue, 8 May 2007, Greg KH wrote:

> > The problem was in drivers/usb/core/config.c in function
> > usb_parse_interface:
> > ---
> > num_ep = num_ep_orig = alt->desc.bNumEndpoints;
> > ...
> > len = sizeof(struct usb_host_endpoint) * num_ep;
> > alt->endpoint = kzalloc(len, GFP_KERNEL);
> > ---
> >
> > num_ep can be 0, as it was in my case, so following patch makes this
> > situation more obvious
> > and clear.

How about instead just doing:

+ num_ep = max(num_ep, 1);
len = sizeof(struct usb_host_endpoint) * num_ep;

Also, wasn't it true at one point that it was legal to call kmalloc() with
a length of 0? ISTR seeing somewhere that it's true for regular malloc().

Alan Stern

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