X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=kernel%2Fexit.c;h=5c8ecbaa19a530cc4d417a897457b0d0318bc39b;hb=d15bcfdbe1818478891d714343f037cfe60875f0;hp=b55ed4cc91044803a45b74d568d83f9727575b8b;hpb=b643b0fdbc59cf6bbb086974b29d2571e9e9f646;p=firefly-linux-kernel-4.4.55.git diff --git a/kernel/exit.c b/kernel/exit.c index b55ed4cc9104..5c8ecbaa19a5 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -7,7 +7,6 @@ #include #include #include -#include #include #include #include @@ -25,8 +24,10 @@ #include #include #include +#include #include #include +#include #include #include #include @@ -42,6 +43,7 @@ #include /* for audit_free() */ #include #include +#include #include #include @@ -82,6 +84,14 @@ static void __exit_signal(struct task_struct *tsk) sighand = rcu_dereference(tsk->sighand); spin_lock(&sighand->siglock); + /* + * Notify that this sighand has been detached. This must + * be called with the tsk->sighand lock held. Also, this + * access tsk->sighand internally, so it must be called + * before tsk->sighand is reset. + */ + signalfd_detach_locked(tsk); + posix_cpu_timers_exit(tsk); if (atomic_dec_and_test(&sig->count)) posix_cpu_timers_exit_group(tsk); @@ -113,6 +123,8 @@ static void __exit_signal(struct task_struct *tsk) sig->nvcsw += tsk->nvcsw; sig->nivcsw += tsk->nivcsw; sig->sched_time += tsk->sched_time; + sig->inblock += task_io_get_inblock(tsk); + sig->oublock += task_io_get_oublock(tsk); sig = NULL; /* Marker for below. */ } @@ -255,26 +267,25 @@ static int has_stopped_jobs(struct pid *pgrp) } /** - * reparent_to_init - Reparent the calling kernel thread to the init task of the pid space that the thread belongs to. + * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd * * If a kernel thread is launched as a result of a system call, or if - * it ever exits, it should generally reparent itself to init so that - * it is correctly cleaned up on exit. + * it ever exits, it should generally reparent itself to kthreadd so it + * isn't in the way of other processes and is correctly cleaned up on exit. * * The various task state such as scheduling policy and priority may have * been inherited from a user process, so we reset them to sane values here. * - * NOTE that reparent_to_init() gives the caller full capabilities. + * NOTE that reparent_to_kthreadd() gives the caller full capabilities. */ -static void reparent_to_init(void) +static void reparent_to_kthreadd(void) { write_lock_irq(&tasklist_lock); ptrace_unlink(current); /* Reparent to init */ remove_parent(current); - current->parent = child_reaper(current); - current->real_parent = child_reaper(current); + current->real_parent = current->parent = kthreadd_task; add_parent(current); /* Set the exit signal to SIGCHLD so we signal init on exit */ @@ -300,12 +311,12 @@ void __set_special_pids(pid_t session, pid_t pgrp) if (process_session(curr) != session) { detach_pid(curr, PIDTYPE_SID); set_signal_session(curr->signal, session); - attach_pid(curr, PIDTYPE_SID, session); + attach_pid(curr, PIDTYPE_SID, find_pid(session)); } if (process_group(curr) != pgrp) { detach_pid(curr, PIDTYPE_PGID); curr->signal->pgrp = pgrp; - attach_pid(curr, PIDTYPE_PGID, pgrp); + attach_pid(curr, PIDTYPE_PGID, find_pid(pgrp)); } } @@ -348,7 +359,7 @@ int disallow_signal(int sig) return -EINVAL; spin_lock_irq(¤t->sighand->siglock); - sigaddset(¤t->blocked, sig); + current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); return 0; @@ -401,7 +412,7 @@ void daemonize(const char *name, ...) current->files = init_task.files; atomic_inc(¤t->files->count); - reparent_to_init(); + reparent_to_kthreadd(); } EXPORT_SYMBOL(daemonize); @@ -751,11 +762,8 @@ static void exit_notify(struct task_struct *tsk) read_lock(&tasklist_lock); spin_lock_irq(&tsk->sighand->siglock); for (t = next_thread(tsk); t != tsk; t = next_thread(t)) - if (!signal_pending(t) && !(t->flags & PF_EXITING)) { - recalc_sigpending_tsk(t); - if (signal_pending(t)) - signal_wake_up(t, 0); - } + if (!signal_pending(t) && !(t->flags & PF_EXITING)) + recalc_sigpending_and_wake(t); spin_unlock_irq(&tsk->sighand->siglock); read_unlock(&tasklist_lock); } @@ -884,13 +892,29 @@ fastcall NORET_TYPE void do_exit(long code) if (unlikely(tsk->flags & PF_EXITING)) { printk(KERN_ALERT "Fixing recursive fault but reboot is needed!\n"); + /* + * We can do this unlocked here. The futex code uses + * this flag just to verify whether the pi state + * cleanup has been done or not. In the worst case it + * loops once more. We pretend that the cleanup was + * done as there is no way to return. Either the + * OWNER_DIED bit is set by now or we push the blocked + * task into the wait for ever nirwana as well. + */ + tsk->flags |= PF_EXITPIDONE; if (tsk->io_context) exit_io_context(); set_current_state(TASK_UNINTERRUPTIBLE); schedule(); } + /* + * tsk->flags are checked in the futex code to protect against + * an exiting task cleaning up the robust pi futexes. + */ + spin_lock_irq(&tsk->pi_lock); tsk->flags |= PF_EXITING; + spin_unlock_irq(&tsk->pi_lock); if (unlikely(in_atomic())) printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", @@ -904,7 +928,7 @@ fastcall NORET_TYPE void do_exit(long code) } group_dead = atomic_dec_and_test(&tsk->signal->live); if (group_dead) { - hrtimer_cancel(&tsk->signal->real_timer); + hrtimer_cancel(&tsk->signal->real_timer); exit_itimers(tsk->signal); } acct_collect(code, group_dead); @@ -957,6 +981,12 @@ fastcall NORET_TYPE void do_exit(long code) * Make sure we are holding no locks: */ debug_check_no_locks_held(tsk); + /* + * We can do this unlocked here. The futex code uses this flag + * just to verify whether the pi state cleanup has been done + * or not. In the worst case it loops once more. + */ + tsk->flags |= PF_EXITPIDONE; if (tsk->io_context) exit_io_context(); @@ -1033,6 +1063,8 @@ asmlinkage void sys_exit_group(int error_code) static int eligible_child(pid_t pid, int options, struct task_struct *p) { + int err; + if (pid > 0) { if (p->pid != pid) return 0; @@ -1066,8 +1098,9 @@ static int eligible_child(pid_t pid, int options, struct task_struct *p) if (delay_group_leader(p)) return 2; - if (security_task_wait(p)) - return 0; + err = security_task_wait(p); + if (err) + return err; return 1; } @@ -1191,6 +1224,12 @@ static int wait_task_zombie(struct task_struct *p, int noreap, p->nvcsw + sig->nvcsw + sig->cnvcsw; psig->cnivcsw += p->nivcsw + sig->nivcsw + sig->cnivcsw; + psig->cinblock += + task_io_get_inblock(p) + + sig->inblock + sig->cinblock; + psig->coublock += + task_io_get_oublock(p) + + sig->oublock + sig->coublock; spin_unlock_irq(&p->parent->sighand->siglock); } @@ -1449,6 +1488,7 @@ static long do_wait(pid_t pid, int options, struct siginfo __user *infop, DECLARE_WAITQUEUE(wait, current); struct task_struct *tsk; int flag, retval; + int allowed, denied; add_wait_queue(¤t->signal->wait_chldexit,&wait); repeat: @@ -1457,6 +1497,7 @@ repeat: * match our criteria, even if we are not able to reap it yet. */ flag = 0; + allowed = denied = 0; current->state = TASK_INTERRUPTIBLE; read_lock(&tasklist_lock); tsk = current; @@ -1472,6 +1513,12 @@ repeat: if (!ret) continue; + if (unlikely(ret < 0)) { + denied = ret; + continue; + } + allowed = 1; + switch (p->state) { case TASK_TRACED: /* @@ -1570,6 +1617,8 @@ check_continued: goto repeat; } retval = -ECHILD; + if (unlikely(denied) && !allowed) + retval = denied; end: current->state = TASK_RUNNING; remove_wait_queue(¤t->signal->wait_chldexit,&wait);