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authorAnton Blanchard <anton@samba.org>2009-09-21 16:57:40 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-09-24 15:31:45 +1000
commitf2053f1a7bf6005b4e81826b1ac8d0b4117c4cf0 (patch)
treed8c69b5ead3bfb5b09d05dd4804ce022cdea8883 /arch/powerpc
parent8bbde7a7062facf8af35bcc9a64cbafe8f36f3cf (diff)
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powerpc/perf_counter: Fix vdso detection
perf_counter uses arch_vma_name() to detect a vdso region which in turn uses current->mm->context.vdso_base. We need to initialise this before doing the mmap or else we fail to detect the vdso. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/vdso.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 3faaf29..94e2df3 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -241,6 +241,13 @@ 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 on
@@ -260,11 +267,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
VM_ALWAYSDUMP,
vdso_pagelist);
- if (rc)
+ if (rc) {
+ current->mm->context.vdso_base = 0;
goto fail_mmapsem;
-
- /* Put vDSO base into mm struct */
- current->mm->context.vdso_base = vdso_base;
+ }
up_write(&mm->mmap_sem);
return 0;