[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>
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 45a3e9a..adfb32a 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -247,6 +247,13 @@
}
/*
+ * 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 @@
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;