Messages in this thread | | | Date | Thu, 25 Jun 2009 11:56:37 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [GIT pull] futex fixes for 2.6.31 |
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On Thu, 25 Jun 2009, Zhang, Yanmin wrote: > On Wed, 2009-06-24 at 21:48 +0200, Thomas Gleixner wrote: > > +static int fault_in_user_writeable(u32 __user *uaddr) > > +{ > > + int ret = get_user_pages(current, current->mm, (unsigned long)uaddr, > > + sizeof(*uaddr), 1, 0, NULL, NULL); > The 4th parameter of get_user_pages means page number. sizeof(*uaddr) is equal to > 4, so you want 4 pages?
Grrr. I looked up the prototype of it in include/linux/mm.h:
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);
len == number of pages ! How intutitive. :(
I guess Linus tripped over it as well. See: http://lkml.org/lkml/2009/6/21/95
> > > In fact, since you're not actually interested in the page, you _could_ > > > just do > > > > > > get_user_pages(tsk, mm, uaddr, 4, 1, 0, NULL, NULL);
Will fix, thanks for noticing!
tglx | |