Re: [Xenomai-help] Bug with Xenomai and xeno_heap: Eeek! page_mapcount(page) went negative!

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

M. Koehrer wrote:
> Hello Gilles,
> 
> I tried a couple of Xenomai/Kernel combinations.
> The result is the following:
> 
> Xeno 2.4.4 and kernel 2.6.25: ok 
> Xeno 2.4.5 and kernel 2.6.25: ok 
> Xeno 2.4.5 and kernel 2.6.26: crash
> (In all tests, I used the adeos patch that was part of the release Xenomai version).
> 
> Thus, some rmap code in kernel 2.6.26 seems to be different than with 2.6.25.
> 
> I hope that helps to find out what is wrong...

Yes, thanks. This is a bug which should have been fixed since then. But 
here is a patch for your version. Could you try it?


diff --git a/include/linux/mm.h b/include/linux/mm.h
index 816cf71..568cd8d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -109,7 +109,7 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_CAN_NONLINEAR 0x08000000	/* Has ->fault & does nonlinear pages */
 #define VM_MIXEDMAP	0x10000000	/* Can contain "struct page" and pure PFN pages */
 
-#define VM_PINNED	0x10000000	/* Disable faults for the vma */
+#define VM_PINNED	0x20000000	/* Disable faults for the vma */
 
 #ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS


-- 
                                                 Gilles.