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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
sys_avr32.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/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/unistd.h>

#include <asm/mman.h>
#include <asm/uaccess.h>

asmlinkage int sys_pipe(unsigned long __user *filedes)
{
	int fd[2];
	int error;

	error = do_pipe(fd);
	if (!error) {
		if (copy_to_user(filedes, fd, sizeof(fd)))
			error = -EFAULT;
	}
	return error;
}

asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
			  unsigned long prot, unsigned long flags,
			  unsigned long fd, off_t offset)
{
	int error = -EBADF;
	struct file *file = NULL;

	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
	if (!(flags & MAP_ANONYMOUS)) {
		file = fget(fd);
		if (!file)
			return error;
	}

	down_write(&current->mm->mmap_sem);
	error = do_mmap_pgoff(file, addr, len, prot, flags, offset);
	up_write(&current->mm->mmap_sem);

	if (file)
		fput(file);
	return error;
}

int kernel_execve(const char *file, char **argv, char **envp)
{
	register long scno asm("r8") = __NR_execve;
	register long sc1 asm("r12") = (long)file;
	register long sc2 asm("r11") = (long)argv;
	register long sc3 asm("r10") = (long)envp;

	asm volatile("scall"
		     : "=r"(sc1)
		     : "r"(scno), "0"(sc1), "r"(sc2), "r"(sc3)
		     : "cc", "memory");
	return sc1;
}
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