/* 0 = success, else # of processes that we failed to stop */ int freeze_processes(void) { int todo; unsigned long start_time; struct task_struct *g, *p; unsigned long flags; printk( "Stopping tasks: " ); start_time = jiffies; 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); 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 ); 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) { 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); read_unlock(&tasklist_lock); return todo; } printk( "|\n" ); BUG_ON(in_atomic()); return 0; }
/* 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; }