Re: 2.6.23-rc4-mm1 build issue: ia64 link error

["Satyam Sharma" <satyam.sharma@gmail.com>]

On 9/8/07, Satyam Sharma <satyam.sharma@gmail.com> wrote:
> On 9/7/07, Andrew Morton <akpm@linux-foundation.org> wrote:
> > > On Fri, 7 Sep 2007 00:34:59 -0700 "Luck, Tony" <tony.luck@intel.com> wrote:
> > > > local symbol 0: discarded in section `.exit.text' from arch/ia64/kernel/built-in.o
> > >
> > > This usually means that there is a static __exit function (or __devexit etc.)
> > > somewhere in the object being linked.  The error message is pretty unhelpful
> > > in figuring out *where* in the module.  Look at the 'mm' patches that touch
> > > arch/ia64/kernel to see if one of them tinkers with __exit* attributes.
> >
> > Confused.  There are >2500 static __exit functions in the tree, including
> > ones like
> >
> > arch/ia64/kernel/esi.c:static void __exit esi_exit (void)
>
> That message means the linker found someone referencing an .exit.text
> function -- on other archs this would've been a section mismatch but on
> ia64 its a link error due to reasons below
> (although it would not have ever caused an oops).
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In general, there's obviously nothing wrong with ia64's policy of discarding
.exit.text at link time (in fact it's a good optimization), and generally most
references from .init.text (or .text) to .exit.text would really be oopsen.

But not so with this case, because with HOTPLUG_CPU=n (which is when
this link error can occur) it's not possible for the notifier to be
called out in
the first place, and especially not for a CPU_DEAD event, which is when
this reference could've occurred in practice.

Anyway, I came across another little thing while investigating this, patch
attached ...


Satyam

[PATCH] ia64 perfmon: Remove exit_pfm_fs()

Because it is dead code and not referenced by anybody else (that file
cannot be built modular).

Signed-off-by: Satyam Sharma <satyam@infradead.org>

---

 arch/ia64/kernel/perfmon.c |    7 -------
 1 file changed, 7 deletions(-)

--- linux-2.6.23-rc4-mm1/arch/ia64/kernel/perfmon.c~fix	2007-09-08 12:54:24.000000000 +0530
+++ linux-2.6.23-rc4-mm1/arch/ia64/kernel/perfmon.c	2007-09-08 12:54:56.000000000 +0530
@@ -1539,13 +1539,6 @@ init_pfm_fs(void)
 	return err;
 }
 
-static void __exit
-exit_pfm_fs(void)
-{
-	unregister_filesystem(&pfm_fs_type);
-	mntput(pfmfs_mnt);
-}
-
 static ssize_t
 pfm_read(struct file *filp, char __user *buf, size_t size, loff_t *ppos)
 {