[PATCH] c/r: prctl: fix build error for no-MMU case

[PATCH] c/r: prctl: fix build error for no-MMU case

[Mark Salter]

Commit 1ad75b9e1 added some address checking to prctl_set_mm()
used by checkpoint-restore. This causes a build error for no-MMU
systems:

   kernel/sys.c: In function 'prctl_set_mm':
   kernel/sys.c:1868:34: error: 'mmap_min_addr' undeclared (first use in this function)

The test for mmap_min_addr doesn't make a lot of sense for no-MMU
code as noted in commit 6e1415467. This patch defines mmap_min_addr
as 0UL in the no-MMU case so that the compiler will optimize away
tests for "addr < mmap_min_addr".

Signed-off-by: Mark Salter <msalter@redhat.com>
---
 include/linux/security.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 3dea6a9..d143b8e 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -118,6 +118,7 @@ void reset_security_ops(void);
 extern unsigned long mmap_min_addr;
 extern unsigned long dac_mmap_min_addr;
 #else
+#define mmap_min_addr		0UL
 #define dac_mmap_min_addr	0UL
 #endif
 
-- 
1.7.9.1

Re: [PATCH] c/r: prctl: fix build error for no-MMU case

[Cyrill Gorcunov]

On Mon, Sep 24, 2012 at 05:41:32PM -0400, Mark Salter wrote:
> Commit 1ad75b9e1 added some address checking to prctl_set_mm()
> used by checkpoint-restore. This causes a build error for no-MMU
> systems:
> 
>    kernel/sys.c: In function 'prctl_set_mm':
>    kernel/sys.c:1868:34: error: 'mmap_min_addr' undeclared (first use in this function)
> 
> The test for mmap_min_addr doesn't make a lot of sense for no-MMU
> code as noted in commit 6e1415467. This patch defines mmap_min_addr
> as 0UL in the no-MMU case so that the compiler will optimize away
> tests for "addr < mmap_min_addr".
> 
> Signed-off-by: Mark Salter <msalter@redhat.com>

Thanks, Mark! I should add that this mmap_min_addr currently
referenced in other parts of code only under CONFIG_MMU so this
definition in header should not break anything.

Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>