lkml.org 
[lkml]   [2007]   [May]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: undefined reference to `__clear_user' (was: Re: [patch 2/13] signal/timer/event fds v10 - signalfd core ...)
On Sun, 13 May 2007 12:28:23 +0200 (CEST) Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> Hi Davide,
>
> On Mon, 2 Apr 2007, Davide Libenzi wrote:
> > --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> > +++ linux-2.6.21-rc5.fds/fs/signalfd.c 2007-04-02 15:06:29.000000000 -0700
>
> > +/*
> > + * Copied from copy_siginfo_to_user() in kernel/signal.c
> > + */
> > +static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
> > + siginfo_t const *kinfo)
> > +{
> > + long err;
> > +
> > + BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
> > +
> > + /*
> > + * Unused memebers should be zero ...
> > + */
> > + err = __clear_user(uinfo, sizeof(*uinfo));
> ^^^^^^^^^^^^
>
> Shouldn't this be `clear_user()'? I don't see any access_ok() calls
> before this call (I do see them in copy_siginfo_to_user() in
> kernel/signal.c), but of course I may miss something...
>
> I only noticed because m68k doesn't have __clear_user(), as this routine
> was never needed by generic code before your change.
>

The vfs does the access_ok() checking on entry to read, write, readv,
writev, pread and pwrite.

I _think_ that covers everything, in which case all the code which
implements reading and writing can use the __ functions. We have a lot of
code which doesn't avail itself of that optimisation though: 12 zillion
sysfs and proc handlers, for a start.

(I think. I only recently noticed this and might have missed a path).
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-05-13 12:47    [W:0.218 / U:0.508 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site