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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
irq.c 
/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * Based on arch/i386/kernel/irq.c
 *   Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 *
 * 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/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel_stat.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/sysdev.h>

/*
 * 'what should we do if we get a hw irq event on an illegal vector'.
 * each architecture has to answer this themselves.
 */
void ack_bad_irq(unsigned int irq)
{
	printk("unexpected IRQ %u\n", irq);
}

#ifdef CONFIG_PROC_FS
int show_interrupts(struct seq_file *p, void *v)
{
	int i = *(loff_t *)v, cpu;
	struct irqaction *action;
	unsigned long flags;

	if (i == 0) {
		seq_puts(p, "           ");
		for_each_online_cpu(cpu)
			seq_printf(p, "CPU%d       ", cpu);
		seq_putc(p, '\n');
	}

	if (i < NR_IRQS) {
		spin_lock_irqsave(&irq_desc[i].lock, flags);
		action = irq_desc[i].action;
		if (!action)
			goto unlock;

		seq_printf(p, "%3d: ", i);
		for_each_online_cpu(cpu)
			seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
		seq_printf(p, " %8s", irq_desc[i].chip->name ? : "-");
		seq_printf(p, "  %s", action->name);
		for (action = action->next; action; action = action->next)
			seq_printf(p, ", %s", action->name);

		seq_putc(p, '\n');
	unlock:
		spin_unlock_irqrestore(&irq_desc[i].lock, flags);
	}

	return 0;
}
#endif
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