From: Dmitry Safonov <dsafonov@virtuozzo.com>
To: <linux-kernel@vger.kernel.org>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>, <0x7f454c46@gmail.com>,
"Cyrill Gorcunov" <gorcunov@openvz.org>,
Andy Lutomirski <luto@kernel.org>, <oleg@redhat.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
<linux-mm@kvack.org>, <x86@kernel.org>
Subject: [PATCH 2/2] x86/vdso: set vdso pointer only after success
Date: Thu, 27 Oct 2016 17:15:16 +0300 [thread overview]
Message-ID: <20161027141516.28447-3-dsafonov@virtuozzo.com> (raw)
In-Reply-To: <20161027141516.28447-1-dsafonov@virtuozzo.com>
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, 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.
Cc: 0x7f454c46@gmail.com
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: oleg@redhat.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: x86@kernel.org
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
---
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 23c881caabd1..e739002427ed 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;
}
--
2.10.1
next prev parent reply other threads:[~2016-10-27 14:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-27 14:15 [PATCH 0/2] x86/vdso: small fixups for map_vdso Dmitry Safonov
2016-10-27 14:15 ` [PATCH 1/2] x86/prctl/uapi: remove ifdef for CHECKPOINT_RESTORE Dmitry Safonov
2016-10-28 6:48 ` [tip:x86/asm] x86/prctl/uapi: Remove #ifdef " tip-bot for Dmitry Safonov
2016-10-27 14:15 ` Dmitry Safonov [this message]
2016-10-27 22:25 ` [PATCH 2/2] x86/vdso: set vdso pointer only after success Andy Lutomirski
2016-10-28 6:49 ` [tip:x86/asm] x86/vdso: Set vDSO " tip-bot for Dmitry Safonov
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