x86: Set context.vdso before installing the mapping

In order to make arch_vma_name() work from inside
install_special_mapping() we need to set the context.vdso
before calling it.

( This is needed for performance counters to be able to track
  this special executable area. )

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 10 insertions, 3 deletions

diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index 1241f118ab56..58bc00f68b12 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -338,6 +338,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
                 }
         }
 
+        current->mm->context.vdso = (void *)addr;
+
         if (compat_uses_vma || !compat) {
                 /*
                  * MAYWRITE to allow gdb to COW and set breakpoints
@@ -358,11 +360,13 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
                         goto up_fail;
         }
 
-        current->mm->context.vdso = (void *)addr;
         current_thread_info()->sysenter_return =
                 VDSO32_SYMBOL(addr, SYSENTER_RETURN);
 
   up_fail:
+        if (ret)
+                current->mm->context.vdso = NULL;
+
         up_write(&mm->mmap_sem);
 
         return ret;
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 7133cdf9098b..93b7a2938b2f 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -115,15 +115,18 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
                 goto up_fail;
         }
 
+        current->mm->context.vdso = (void *)addr;
+
         ret = install_special_mapping(mm, addr, vdso_size,
                                       VM_READ|VM_EXEC|
                                       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
                                       VM_ALWAYSDUMP,
                                       vdso_pages);
-        if (ret)
+        if (ret) {
+                current->mm->context.vdso = NULL;
                 goto up_fail;
+        }
 
-        current->mm->context.vdso = (void *)addr;
 up_fail:
         up_write(&mm->mmap_sem);
         return ret;