Re: [LTP] [PATCH] mprotect04: fix powerpc crash when copying exec_func

[Jan S. <jst...@re...>]

----- Original Message -----
> From: "Cyril Hrubis" <ch...@su...>
> To: "Jan Stancek" <jst...@re...>
> Cc: ltp...@li...
> Sent: Wednesday, 9 September, 2015 3:26:42 PM
> Subject: Re: [LTP] [PATCH] mprotect04: fix powerpc crash when copying exec_func
> 
> Hi!
> > > > I'm seeing this on RHEL6.7 kernel, I haven't tried latest upstream yet.
> > > 
> > > Ah, you are right, the memory is not touched in the write_null()
> > > function at all.
> > 
> > Right, I got confused by "access_ok(VERIFY_READ, buf, count)"
> > in vfs_write(), but after reading code and comments it's clear it
> > only checks if range _may_ be valid:
> >  * access_ok: - Checks if a user space pointer is valid
> >  ...
> >  * Returns true (nonzero) if the memory block may be valid, false (zero)
> >  * if it is definitely invalid.
> >  *
> >  * Note that, depending on architecture, this function probably just
> >  * checks that the pointer is in the user space range - after calling
> >  * this function, memory access functions may still return -EFAULT.
> 
> I do not have further questions. Acked.

Pushed.

Regards,
Jan

> 
> --
> Cyril Hrubis
> ch...@su...
>