#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/module.h>
+#include <linux/syscalls.h>
+#include <linux/freezer.h>
/*
* Timeout for stopping processes
*/
-#define TIMEOUT (6 * HZ)
+#define TIMEOUT (20 * HZ)
+#define FREEZER_KERNEL_THREADS 0
+#define FREEZER_USER_SPACE 1
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))
+ (p->exit_state == EXIT_DEAD))
return 0;
return 1;
}
long save;
save = current->state;
pr_debug("%s entered refrigerator\n", current->comm);
- printk("=");
frozen_process(current);
spin_lock_irq(¤t->sighand->siglock);
current->state = save;
}
-/* 0 = success, else # of processes that we failed to stop */
-int freeze_processes(void)
+static inline void freeze_process(struct task_struct *p)
+{
+ unsigned long flags;
+
+ if (!freezing(p)) {
+ rmb();
+ if (!frozen(p)) {
+ if (p->state == TASK_STOPPED)
+ force_sig_specific(SIGSTOP, p);
+
+ freeze(p);
+ spin_lock_irqsave(&p->sighand->siglock, flags);
+ signal_wake_up(p, p->state == TASK_STOPPED);
+ spin_unlock_irqrestore(&p->sighand->siglock, flags);
+ }
+ }
+}
+
+static void cancel_freezing(struct task_struct *p)
{
- int todo;
- unsigned long start_time;
- struct task_struct *g, *p;
unsigned long flags;
- printk( "Stopping tasks: " );
- start_time = jiffies;
+ if (freezing(p)) {
+ pr_debug(" clean up: %s\n", p->comm);
+ do_not_freeze(p);
+ spin_lock_irqsave(&p->sighand->siglock, flags);
+ recalc_sigpending_tsk(p);
+ spin_unlock_irqrestore(&p->sighand->siglock, flags);
+ }
+}
+
+static inline int is_user_space(struct task_struct *p)
+{
+ return p->mm && !(p->flags & PF_BORROWED_MM);
+}
+
+static unsigned int try_to_freeze_tasks(int freeze_user_space)
+{
+ struct task_struct *g, *p;
+ unsigned long end_time;
+ unsigned int todo;
+
+ end_time = jiffies + TIMEOUT;
do {
todo = 0;
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (!freezeable(p))
continue;
+
if (frozen(p))
continue;
- freeze(p);
- spin_lock_irqsave(&p->sighand->siglock, flags);
- signal_wake_up(p, 0);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
+ if (p->state == TASK_TRACED && frozen(p->parent)) {
+ cancel_freezing(p);
+ continue;
+ }
+ if (is_user_space(p)) {
+ if (!freeze_user_space)
+ continue;
+
+ /* Freeze the task unless there is a vfork
+ * completion pending
+ */
+ if (!p->vfork_done)
+ freeze_process(p);
+ } else {
+ if (freeze_user_space)
+ continue;
+
+ freeze_process(p);
+ }
todo++;
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
yield(); /* Yield is okay here */
- if (todo && time_after(jiffies, start_time + TIMEOUT)) {
- printk( "\n" );
- printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo );
+ if (todo && time_after(jiffies, end_time))
break;
- }
- } while(todo);
+ } 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) {
+ /* 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.
+ */
+ printk("\n");
+ printk(KERN_ERR "Stopping %s timed out after %d seconds "
+ "(%d tasks refusing to freeze):\n",
+ freeze_user_space ? "user space processes" :
+ "kernel threads",
+ TIMEOUT / HZ, todo);
read_lock(&tasklist_lock);
- do_each_thread(g, p)
- 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);
+ do_each_thread(g, p) {
+ if (is_user_space(p) == !freeze_user_space)
+ continue;
+
+ if (freezeable(p) && !frozen(p))
+ printk(KERN_ERR " %s\n", p->comm);
+
+ cancel_freezing(p);
+ } while_each_thread(g, p);
read_unlock(&tasklist_lock);
- return todo;
}
- printk( "|\n" );
+ return todo;
+}
+
+/**
+ * freeze_processes - tell processes to enter the refrigerator
+ *
+ * Returns 0 on success, or the number of processes that didn't freeze,
+ * although they were told to.
+ */
+int freeze_processes(void)
+{
+ unsigned int nr_unfrozen;
+
+ printk("Stopping tasks ... ");
+ nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE);
+ if (nr_unfrozen)
+ return nr_unfrozen;
+
+ sys_sync();
+ nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
+ if (nr_unfrozen)
+ return nr_unfrozen;
+
+ printk("done.\n");
BUG_ON(in_atomic());
return 0;
}
-void thaw_processes(void)
+static void thaw_tasks(int thaw_user_space)
{
struct task_struct *g, *p;
- printk( "Restarting tasks..." );
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (!freezeable(p))
continue;
+
+ if (is_user_space(p) == !thaw_user_space)
+ continue;
+
if (!thaw_process(p))
- printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
+ printk(KERN_WARNING " Strange, %s not stopped\n",
+ p->comm );
} while_each_thread(g, p);
-
read_unlock(&tasklist_lock);
+}
+
+void thaw_processes(void)
+{
+ printk("Restarting tasks ... ");
+ thaw_tasks(FREEZER_KERNEL_THREADS);
+ thaw_tasks(FREEZER_USER_SPACE);
schedule();
- printk( " done\n" );
+ printk("done.\n");
}
EXPORT_SYMBOL(refrigerator);
git://git.onelab.eu / linux-2.6.git / blobdiff