On Fri, Dec 18, 2015 at 12:12:05AM +0100, Arnd Bergmann wrote:
> On Thursday 17 December 2015 17:58:52 Bamvor Jian Zhang wrote:
> > The arg of ioctl in ppdev is the pointer of integer except the
> > timeval in PPSETTIME, PPGETTIME. Different size of timeval
> > is already supported by the previous patches. So, it is safe
> > to add compat support.
> > 
> > Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
> > 
> 
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> 
> (I think I replied with the reviewed-by tag before to this patch)

I was testing this series today. And it is breaking my userspace code. I
am attaching my userspace code for you to check. Its very simple
userspace code:
1: open
2: ioctl to claim
3: ioctl - PPGETTIME
4: ioctl - PPSETTIME
5: ioctl - PPGETTIME
6: ioctl - release
7: close

Without this series it works as expected.

With this series applied, the userspace code prints the error message:
PPNEGOT: Bad address

I traced it with strace and:
ioctl(3, PPGETTIME, 0xbfe91508)         = -1 EFAULT (Bad address)

regards
sudip