Commit-ID: 67dece7d4c5841e84a3c795e79bf0dcd5be54f55
Gitweb: http://git.kernel.org/tip/67dece7d4c5841e84a3c795e79bf0dcd5be54f55
Author: Dmitry Safonov <[email protected]>
AuthorDate: Thu, 27 Oct 2016 17:15:16 +0300
Committer: Ingo Molnar <[email protected]>
CommitDate: Fri, 28 Oct 2016 08:15:55 +0200
x86/vdso: Set vDSO pointer only after success
Those pointers were initialized before call to _install_special_mapping()
after the commit:
f7b6eb3fa072 ("x86: Set context.vdso before installing the mapping")
This is not required anymore as special mappings have their vma name and
don't use arch_vma_name() after commit:
a62c34bd2a8a ("x86, mm: Improve _install_special_mapping and fix x86 vdso
naming")
So, this way to init looks less entangled.
I even belive that we can remove NULL initializers:
- on failure load_elf_binary() will not start a new thread;
- arch_prctl will have the same pointers as before syscall.
Signed-off-by: Dmitry Safonov <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: [email protected]
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/entry/vdso/vma.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 23c881c..e739002 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -161,8 +161,6 @@ static int map_vdso(const struct vdso_image *image,
unsigned long addr)
}
text_start = addr - image->sym_vvar_start;
- current->mm->context.vdso = (void __user *)text_start;
- current->mm->context.vdso_image = image;
/*
* MAYWRITE to allow gdb to COW and set breakpoints
@@ -189,14 +187,12 @@ static int map_vdso(const struct vdso_image *image,
unsigned long addr)
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
do_munmap(mm, text_start, image->size);
+ } else {
+ current->mm->context.vdso = (void __user *)text_start;
+ current->mm->context.vdso_image = image;
}
up_fail:
- if (ret) {
- current->mm->context.vdso = NULL;
- current->mm->context.vdso_image = NULL;
- }
-
up_write(&mm->mmap_sem);
return ret;
}
