linux-kernel - [PATCH 1/2] exec: kill the unnecessary mm->def_flags setting in load_elf

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Message-ID: <20140122174627.GB29710@redhat.com>
Date:	Wed, 22 Jan 2014 18:46:27 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Alex Thorlton <athorlton@....com>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	"Kirill A. Shutemov" <kirill@...temov.name>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Rik van Riel <riel@...hat.com>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Andy Lutomirski <luto@...capital.net>,
	Al Viro <viro@...iv.linux.org.uk>,
	Kees Cook <keescook@...omium.org>,
	Andrea Arcangeli <aarcange@...hat.com>
Subject: [PATCH 1/2] exec: kill the unnecessary mm->def_flags setting in
	load_elf_binary()

load_elf_binary() sets current->mm->def_flags = def_flags and
def_flags is always zero. Not only this looks strange, this is
unnecessary because mm_init() has already set ->def_flags = 0.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 fs/binfmt_elf.c |    4 ----
 1 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 571a423..19f569c 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -582,7 +582,6 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	unsigned long start_code, end_code, start_data, end_data;
 	unsigned long reloc_func_desc __maybe_unused = 0;
 	int executable_stack = EXSTACK_DEFAULT;
-	unsigned long def_flags = 0;
 	struct pt_regs *regs = current_pt_regs();
 	struct {
 		struct elfhdr elf_ex;
@@ -722,9 +721,6 @@ static int load_elf_binary(struct linux_binprm *bprm)
 	if (retval)
 		goto out_free_dentry;
 
-	/* OK, This is the point of no return */
-	current->mm->def_flags = def_flags;
-
 	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
 	   may depend on the personality.  */
 	SET_PERSONALITY(loc->elf_ex);
-- 
1.5.5.1


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