Re: Build error: `.exit.text' referenced in section `.rodata'

[Thorsten Kranzkowski <dl8bcu@xxxxxxxxx>]

On Sun, May 11, 2008 at 11:55:07AM -0500, James Bottomley wrote:
> On Sun, 2008-05-11 at 15:19 +0000, Thorsten Kranzkowski wrote:
> > Hello,
> > 
> > compiling 2.6.26-rc1 (latest git) on an Alpha DS20 (ev6, everything built in,
> > gcc version 4.1.2) fails with the following link errors:
> > 
> >   CC      init/version.o
> >   LD      init/built-in.o
> >   LD      .tmp_vmlinux1
> > `.exit.text' referenced in section `.rodata' of drivers/built-in.o: defined in discarded section `.exit.text' of drivers/built-in.o


> > I believe the problem is static int sd_major(int major_idx) being inlined
> > into exit_sd(). IIUC the switch statement therein uses sort of a jump table.
> > And the targets of this jump table can not be resolved because the section
> > they live in is just discarded.
> 
> It's plausible.  However, my version of gcc (4.2.3) doesn't actually
> inline this; even when I force it to by adding the inline directive to
> sd_major() I don't see the problem.  I suspect it might be a gcc bug
> 
> > 
> > applying this patch makes the problem go away:
> > 
> > Signed-off-by: Thorsten Kranzkowski <dl8bcu@xxxxxxxxx>
> > 
> > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> > index 01cefbb..adf79ad 100644
> > --- a/drivers/scsi/sd.c
> > +++ b/drivers/scsi/sd.c
> > @@ -1913,7 +1913,7 @@ err_out:
> >   *
> >   *	Note: this function unregisters this driver from the scsi mid-level.
> >   **/
> > -static void __exit exit_sd(void)
> > +static void exit_sd(void)
> 
> We can't really do this because that text genuinely does belong in the
> exit section.  We might be able to fix it up on the alpha by just adding
> the noinline directive to sd_major.  Does this work?

Yes, this works as well! Thanks!

   text    data     bss     dec     hex filename
6834571  504320  397508 7736399  760c4f vmlinux
6835267  504056  397508 7736831  760dff vmlinux-exit_sd-not-in-.exit.text

Tested-by: Thorsten Kranzkowski <dl8bcu@xxxxxxxxx>
 
Now I'll update gcc and try again with gcc 4.2.3.

> James
> 
> ---
> 
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 01cefbb..060ba18 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -280,7 +280,7 @@ static struct scsi_driver sd_template = {
>   * As we stay compatible with our numbering scheme, we can reuse 
>   * the well-know SCSI majors 8, 65--71, 136--143.
>   */
> -static int sd_major(int major_idx)
> +static noinline int sd_major(int major_idx)
>  {
>  	switch (major_idx) {
>  	case 0:
> 
> 

Thorsten.

-- 
| Thorsten Kranzkowski        Internet: dl8bcu@xxxxxxxxx                      |
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