![Pavel Machek](/assets/img/avatar_default.png)
strace /bin/bash misbehaves after resume; this fixes it. (akpm: it's scary calling refrigerator() in state TASK_TRACED, but it seems to do the right thing). Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
165 lines
3.8 KiB
C
165 lines
3.8 KiB
C
/*
|
|
* drivers/power/process.c - Functions for starting/stopping processes on
|
|
* suspend transitions.
|
|
*
|
|
* Originally from swsusp.
|
|
*/
|
|
|
|
|
|
#undef DEBUG
|
|
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/suspend.h>
|
|
#include <linux/module.h>
|
|
#include <linux/syscalls.h>
|
|
|
|
/*
|
|
* Timeout for stopping processes
|
|
*/
|
|
#define TIMEOUT (20 * HZ)
|
|
|
|
|
|
static inline int freezeable(struct task_struct * p)
|
|
{
|
|
if ((p == current) ||
|
|
(p->flags & PF_NOFREEZE) ||
|
|
(p->exit_state == EXIT_ZOMBIE) ||
|
|
(p->exit_state == EXIT_DEAD) ||
|
|
(p->state == TASK_STOPPED))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/* Refrigerator is place where frozen processes are stored :-). */
|
|
void refrigerator(void)
|
|
{
|
|
/* Hmm, should we be allowed to suspend when there are realtime
|
|
processes around? */
|
|
long save;
|
|
save = current->state;
|
|
pr_debug("%s entered refrigerator\n", current->comm);
|
|
printk("=");
|
|
|
|
frozen_process(current);
|
|
spin_lock_irq(¤t->sighand->siglock);
|
|
recalc_sigpending(); /* We sent fake signal, clean it up */
|
|
spin_unlock_irq(¤t->sighand->siglock);
|
|
|
|
while (frozen(current)) {
|
|
current->state = TASK_UNINTERRUPTIBLE;
|
|
schedule();
|
|
}
|
|
pr_debug("%s left refrigerator\n", current->comm);
|
|
current->state = save;
|
|
}
|
|
|
|
static inline void freeze_process(struct task_struct *p)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (!freezing(p)) {
|
|
freeze(p);
|
|
spin_lock_irqsave(&p->sighand->siglock, flags);
|
|
signal_wake_up(p, 0);
|
|
spin_unlock_irqrestore(&p->sighand->siglock, flags);
|
|
}
|
|
}
|
|
|
|
/* 0 = success, else # of processes that we failed to stop */
|
|
int freeze_processes(void)
|
|
{
|
|
int todo, nr_user, user_frozen;
|
|
unsigned long start_time;
|
|
struct task_struct *g, *p;
|
|
unsigned long flags;
|
|
|
|
printk( "Stopping tasks: " );
|
|
start_time = jiffies;
|
|
user_frozen = 0;
|
|
do {
|
|
nr_user = todo = 0;
|
|
read_lock(&tasklist_lock);
|
|
do_each_thread(g, p) {
|
|
if (!freezeable(p))
|
|
continue;
|
|
if (frozen(p))
|
|
continue;
|
|
if (p->mm && !(p->flags & PF_BORROWED_MM)) {
|
|
/* The task is a user-space one.
|
|
* Freeze it unless there's a vfork completion
|
|
* pending
|
|
*/
|
|
if (!p->vfork_done)
|
|
freeze_process(p);
|
|
nr_user++;
|
|
} else {
|
|
/* Freeze only if the user space is frozen */
|
|
if (user_frozen)
|
|
freeze_process(p);
|
|
todo++;
|
|
}
|
|
} while_each_thread(g, p);
|
|
read_unlock(&tasklist_lock);
|
|
todo += nr_user;
|
|
if (!user_frozen && !nr_user) {
|
|
sys_sync();
|
|
start_time = jiffies;
|
|
}
|
|
user_frozen = !nr_user;
|
|
yield(); /* Yield is okay here */
|
|
if (todo && time_after(jiffies, start_time + TIMEOUT))
|
|
break;
|
|
} while(todo);
|
|
|
|
/* This does not unfreeze processes that are already frozen
|
|
* (we have slightly ugly calling convention in that respect,
|
|
* and caller must call thaw_processes() if something fails),
|
|
* but it cleans up leftover PF_FREEZE requests.
|
|
*/
|
|
if (todo) {
|
|
printk( "\n" );
|
|
printk(KERN_ERR " stopping tasks timed out "
|
|
"after %d seconds (%d tasks remaining):\n",
|
|
TIMEOUT / HZ, todo);
|
|
read_lock(&tasklist_lock);
|
|
do_each_thread(g, p) {
|
|
if (freezeable(p) && !frozen(p))
|
|
printk(KERN_ERR " %s\n", p->comm);
|
|
if (freezing(p)) {
|
|
pr_debug(" clean up: %s\n", p->comm);
|
|
p->flags &= ~PF_FREEZE;
|
|
spin_lock_irqsave(&p->sighand->siglock, flags);
|
|
recalc_sigpending_tsk(p);
|
|
spin_unlock_irqrestore(&p->sighand->siglock, flags);
|
|
}
|
|
} while_each_thread(g, p);
|
|
read_unlock(&tasklist_lock);
|
|
return todo;
|
|
}
|
|
|
|
printk( "|\n" );
|
|
BUG_ON(in_atomic());
|
|
return 0;
|
|
}
|
|
|
|
void thaw_processes(void)
|
|
{
|
|
struct task_struct *g, *p;
|
|
|
|
printk( "Restarting tasks..." );
|
|
read_lock(&tasklist_lock);
|
|
do_each_thread(g, p) {
|
|
if (!freezeable(p))
|
|
continue;
|
|
if (!thaw_process(p))
|
|
printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
|
|
} while_each_thread(g, p);
|
|
|
|
read_unlock(&tasklist_lock);
|
|
schedule();
|
|
printk( " done\n" );
|
|
}
|
|
|
|
EXPORT_SYMBOL(refrigerator);
|