Hi Michael,
On Wed, Dec 02, 2015 at 05:14:47PM +0100, Michael Kerrisk (man-pages) wrote:
> Hello Namhyung Kim,
>
> I need some explanation here. This is not a simple
> typo fix, I believe. Why do you think the current text
> is wrong?
Actually la_pltenter() is called regardless of the value of framesizep
but la_pltexit() is called only if la_pltenter() returns with non-zero
framesizep set. I spent long time to figure out why la_pltexit() is
not called at all.
Quoting comments in glibc/sysdeps/x86_64/dl-trampoline.h:
/* There's nothing in the frame size, so there
will be no call to the _dl_call_pltexit. */
and
/* At this point we need to prepare new stack for the function
which has to be called. We copy the original stack to a
temporary buffer of the size specified by the 'framesize'
returned from _dl_profile_fixup */
I think it's because it needs to preserve 'inregs' to be passed to
la_pltexit().
The _dl_profile_fixup() sets the '*framesizep' to maximum value of
what la_pltenter() sets. Please see glibc/elf/dl-runtime.c file.
Thanks,
Namhyung
>
> On 11/03/2015 01:18 AM, Namhyung Kim wrote:
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxx>
> > ---
> > man7/rtld-audit.7 | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/man7/rtld-audit.7 b/man7/rtld-audit.7
> > index d0f7563..643bc57 100644
> > --- a/man7/rtld-audit.7
> > +++ b/man7/rtld-audit.7
> > @@ -400,7 +400,7 @@ If different
> > invocations for this symbol return different values,
> > then the maximum returned value is used.
> > The
> > -.BR la_pltenter ()
> > +.BR la_pltexit ()
> > function is called only if this buffer is
> > explicitly set to a suitable value.
> >
> >
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
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