[S390] perf_counter: fix vdso detection

s390 version of f2053f1a "powerpc/perf_counter: Fix vdso detection".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 45a3e9a7ae21..adfb32aa6d59 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -247,6 +247,13 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
         }
 
         /*
+         * Put vDSO base into mm struct. We need to do this before calling
+         * install_special_mapping or the perf counter mmap tracking code
+         * will fail to recognise it as a vDSO (since arch_vma_name fails).
+         */
+        current->mm->context.vdso_base = vdso_base;
+
+        /*
          * our vma flags don't have VM_WRITE so by default, the process
          * isn't allowed to write those pages.
          * gdb can break that with ptrace interface, and thus trigger COW
@@ -267,14 +274,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
                                      VM_ALWAYSDUMP,
                                      vdso_pagelist);
         if (rc)
-                goto out_up;
-
-        /* Put vDSO base into mm struct */
-        current->mm->context.vdso_base = vdso_base;
-
-        up_write(&mm->mmap_sem);
-        return 0;
-
+                current->mm->context.vdso_base = 0;
 out_up:
         up_write(&mm->mmap_sem);
         return rc;