markers: fix duplicate modpost entry

When a kernel was rebuilt, the previous Module.markers was not cleared.
It caused markers with different format strings to appear as duplicates
when a markers was changed.  This problem is present since
scripts/mod/modpost.c started to generate Module.markers, commit
b2e3e658b344c6bcfb8fb694100ab2f2b5b2edb0

It therefore applies to 2.6.25, 2.6.26 and linux-next.

I merely merged the patches from Roland, Wenji and Takashi here.

Credits to
Roland McGrath <roland@redhat.com>
Wenji Huang <wenji.huang@oracle.com>
and
Takashi Nishiie <t-nishiie@np.css.fujitsu.com>

for providing the individual fixes.

- Changelog :
  - Integrated Takashi's Makefile modification to clear Module.markers upon
    make clean.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Roland McGrath <roland@redhat.com>
Cc: Wenji Huang <wenji.huang@oracle.com>
Cc: Takashi Nishiie <t-nishiie@np.css.fujitsu.com>
Cc: <stable@kernel.org>		[2.6.25.x, 2.6.26.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 3 insertions, 1 deletions

diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 17092d6c7db3..9ee9783aea57 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -101,6 +101,7 @@ quiet_cmd_kernel-mod = MODPOST $@
       cmd_kernel-mod = $(modpost) $@
 
 vmlinux.o: FORCE
+        @rm -fr $(kernelmarkersfile)
         $(call cmd,kernel-mod)
 
 # Declare generated files as targets for modpost
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index a07f91aac920..8f038e6d5f98 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1992,7 +1992,8 @@ static void read_markers(const char *fname)
                         mod->skip = 1;
                 }
 
-                add_marker(mod, marker, fmt);
+                if (!mod->skip)
+                        add_marker(mod, marker, fmt);
         }
         return;
 fail: