Re: [patch] i386, vdso=[0|1] boot option and /proc/sys/vm/vdso_enabled

[Zachary Amsden]

Andrew Morton wrote:
> vmm:/home/akpm# echo 1 > /proc/sys/vm/vdso_enabled 
> vmm:/home/akpm# 
> vmm:/home/akpm> ls -l
> zsh: segmentation fault  ls -l
>
>   
> > That could tell us whether 
> > it's an init bug or a glibc bug.
> >     
>
> It tells us neither.  This could be a new kernel bug which only certain old
> userspace setups are known to trigger.  Until we know exactly why this is
> occurring, we don't know where the bug is.
>
> And once we've worked that thing out, and if we determine that the bug is
> in userspace then we might be able to craft the patch in such a fashion
> that the old userspace continues to work, which would be a win.
>   

Please try my patch - sent earlier, but attached again.  It will tell 
you with 100% confidence if the problem is with userspace expecting the 
vsyscall page to be at a particular address.
Index: linux-2.6.17-rc/include/asm-i386/fixmap.h
===================================================================
--- linux-2.6.17-rc.orig/include/asm-i386/fixmap.h	2006-03-19 21:53:29.000000000 -0800
+++ linux-2.6.17-rc/include/asm-i386/fixmap.h	2006-05-19 18:16:00.000000000 -0700
@@ -20,7 +20,7 @@
  * Leave one empty page between vmalloc'ed areas and
  * the start of the fixmap.
  */
-#define __FIXADDR_TOP	0xfffff000
+#define __FIXADDR_TOP	0xffbff000
 
 #ifndef __ASSEMBLY__
 #include <linux/kernel.h>