Re: [usb:usb-next 50/92] drivers/usb/serial/pl2303.c:149 pl2303_vendor_read() error: doing dma on the stack (buf)

[Dan Carpenter <dan.carpenter@oracle.com>]

On Sat, Jan 04, 2014 at 12:23:41PM +0100, Johan Hovold wrote:
> On Sat, Jan 04, 2014 at 05:28:35AM +0800, kbuild test robot wrote:
> > tree:   git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-next
> > head:   bd6383c81d5f33e01688a87c50a8d3a878aa43d5
> > commit: 362eb02603be7bb835c47f2cf585954a5080449d [50/92] USB: pl2303: add error handling to vendor read and write functions
> > 
> > New smatch warnings:
> > drivers/usb/serial/pl2303.c:149 pl2303_vendor_read() error: doing dma on the stack (buf)
> >
> > Old smatch warnings:
> > drivers/usb/serial/pl2303.c:673 pl2303_ioctl() warn: check that 'ser' doesn't leak information (struct has a hole after 'iomem_reg_shift')
> > 
> > vim +149 drivers/usb/serial/pl2303.c
> > 
> > 8bf769eb Johan Hovold   2012-10-15  133  };
> > 8bf769eb Johan Hovold   2012-10-15  134  
> > ^1da177e Linus Torvalds 2005-04-16  135  struct pl2303_private {
> > ^1da177e Linus Torvalds 2005-04-16  136  	spinlock_t lock;
> > ^1da177e Linus Torvalds 2005-04-16  137  	u8 line_control;
> > ^1da177e Linus Torvalds 2005-04-16  138  	u8 line_status;
> > 623c8263 Johan Hovold   2013-12-29  139  
> > 623c8263 Johan Hovold   2013-12-29  140  	u8 line_settings[7];
> > ^1da177e Linus Torvalds 2005-04-16  141  };
> > ^1da177e Linus Torvalds 2005-04-16  142  
> > 362eb026 Johan Hovold   2013-12-29  143  static int pl2303_vendor_read(struct usb_serial *serial, u16 value,
> > 362eb026 Johan Hovold   2013-12-29  144  							unsigned char buf[1])
> 
> This is a false positive. A pointer passed as an array is still just a
> pointer (and in this case the buffer it points to is not on the stack).
> 
> Looks like smatch needs to be updated.
> 

Thanks.  I have written a fix for this and will push next week.

regards,
dan carpenter