+ modules-dont-export-section-names-of-empty-sections-via-sysfs.patch added to -mm tree

+ modules-dont-export-section-names-of-empty-sections-via-sysfs.patch added to -mm tree

[akpm]

The patch titled
     modules: don't export section names of empty sections via sysfs
has been added to the -mm tree.  Its filename is
     modules-dont-export-section-names-of-empty-sections-via-sysfs.patch

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------------------------------------------------------
Subject: modules: don't export section names of empty sections via sysfs
From: Helge Deller <deller@gmx.de>

On the parisc architecture we face for each and every loaded kernel module
this kernel "badness warning":

  sysfs: cannot create duplicate filename '/module/ac97_bus/sections/.text'
  Badness at fs/sysfs/dir.c:487

Reason for that is, that on parisc all kernel modules do have multiple
.text sections due to the usage of the -ffunction-sections compiler flag
which is needed to reach all jump targets on this platform.

An objdump on such a kernel module gives:
Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .note.gnu.build-id 00000024  00000000  00000000  00000034  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  1 .text         00000000  00000000  00000000  00000058  2**0
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
  2 .text.ac97_bus_match 0000001c  00000000  00000000  00000058  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
  3 .text         00000000  00000000  00000000  000000d4  2**0
                  CONTENTS, ALLOC, LOAD, READONLY, CODE

...

Since the .text sections are empty (size of 0 bytes) and won't be loaded
by the kernel module loader anyway, I don't see a reason why such sections
need to be listed under /sys/module/<module_name>/sections/<section_name>
either.

The attached patch does solve this issue by not exporting section names
which are empty.

This fixes bugzilla http://bugzilla.kernel.org/show_bug.cgi?id=14703

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/module.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff -puN kernel/module.c~modules-dont-export-section-names-of-empty-sections-via-sysfs kernel/module.c
--- a/kernel/module.c~modules-dont-export-section-names-of-empty-sections-via-sysfs
+++ a/kernel/module.c
@@ -1037,7 +1037,8 @@ static void add_sect_attrs(struct module
 
 	/* Count loaded sections and allocate structures */
 	for (i = 0; i < nsect; i++)
-		if (sechdrs[i].sh_flags & SHF_ALLOC)
+		if (sechdrs[i].sh_flags & SHF_ALLOC
+		    && sechdrs[i].sh_size)
 			nloaded++;
 	size[0] = ALIGN(sizeof(*sect_attrs)
 			+ nloaded * sizeof(sect_attrs->attrs[0]),
@@ -1057,6 +1058,8 @@ static void add_sect_attrs(struct module
 	for (i = 0; i < nsect; i++) {
 		if (! (sechdrs[i].sh_flags & SHF_ALLOC))
 			continue;
+		if (!sechdrs[i].sh_size)
+			continue;
 		sattr->address = sechdrs[i].sh_addr;
 		sattr->name = kstrdup(secstrings + sechdrs[i].sh_name,
 					GFP_KERNEL);
_

Patches currently in -mm which might be from deller@gmx.de are

origin.patch
linux-next.patch
modules-dont-export-section-names-of-empty-sections-via-sysfs.patch
kernel-sysc-implement-prctlpr_get_endian-for-all-architectures.patch