Messages in this thread Patch in this message | | | Date | Thu, 27 Oct 2016 23:49:25 -0700 | From | tip-bot for Dmitry Safonov <> | Subject | [tip:x86/asm] x86/vdso: Set vDSO pointer only after success |
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Commit-ID: 67dece7d4c5841e84a3c795e79bf0dcd5be54f55 Gitweb: http://git.kernel.org/tip/67dece7d4c5841e84a3c795e79bf0dcd5be54f55 Author: Dmitry Safonov <dsafonov@virtuozzo.com> AuthorDate: Thu, 27 Oct 2016 17:15:16 +0300 Committer: Ingo Molnar <mingo@kernel.org> 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 <dsafonov@virtuozzo.com> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: 0x7f454c46@gmail.com Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Cc: oleg@redhat.com Link: http://lkml.kernel.org/r/20161027141516.28447-3-dsafonov@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- 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; }
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