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Revision a98fdcef941e107eeabae622d85a1f476f25a160 authored by Oleg Nesterov on 14 January 2008, 21:02:37 UTC, committed by Linus Torvalds on 14 January 2008, 21:23:00 UTC 
fix the "remove task_ppid_nr_ns" commit
 
Commit 84427eaef1fb91704c7112bdb598c810003b99f3 (remove task_ppid_nr_ns)
moved the task_tgid_nr_ns(task->real_parent) outside of lock_task_sighand().
This is wrong, ->real_parent could be freed/reused.

Both ->parent/real_parent point to nothing after __exit_signal() because
we remove the child from ->children list, and thus the child can't be
reparented when its parent exits.

rcu_read_lock() protects ->parent/real_parent, but _only_ if we know it was
valid before we take rcu lock.

Revert this part of the patch.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 4fd3670
Raw File
init_task.c 
/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/init_task.h>
#include <linux/mqueue.h>

#include <asm/pgtable.h>

static struct fs_struct init_fs = INIT_FS;
static struct files_struct init_files = INIT_FILES;
static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
struct mm_struct init_mm = INIT_MM(init_mm);

EXPORT_SYMBOL(init_mm);

/*
 * Initial thread structure. Must be aligned on an 8192-byte boundary.
 */
union thread_union init_thread_union
	__attribute__((__section__(".data.init_task"))) =
		{ INIT_THREAD_INFO(init_task) };

/*
 * Initial task structure.
 *
 * All other task structs will be allocated on slabs in fork.c
 */
struct task_struct init_task = INIT_TASK(init_task);

EXPORT_SYMBOL(init_task);
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