diff options
| -rw-r--r-- | kernel/signal.c | 69 |
1 files changed, 17 insertions, 52 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index e99ec2f891a..e3bdec91462 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1682,8 +1682,7 @@ out: * Returns nonzero if we've actually stopped and released the siglock. * Returns zero if we didn't stop and still hold the siglock. */ -static int -do_signal_stop(int signr) +static int do_signal_stop(int signr) { struct signal_struct *sig = current->signal; struct sighand_struct *sighand = current->sighand; @@ -1703,7 +1702,6 @@ do_signal_stop(int signr) set_current_state(TASK_STOPPED); if (stop_count == 0) sig->flags = SIGNAL_STOP_STOPPED; - spin_unlock_irq(&sighand->siglock); } else if (thread_group_empty(current)) { /* @@ -1712,71 +1710,38 @@ do_signal_stop(int signr) current->exit_code = current->signal->group_exit_code = signr; set_current_state(TASK_STOPPED); sig->flags = SIGNAL_STOP_STOPPED; - spin_unlock_irq(&sighand->siglock); } else { /* + * (sig->group_stop_count == 0) * There is no group stop already in progress. - * We must initiate one now, but that requires - * dropping siglock to get both the tasklist lock - * and siglock again in the proper order. Note that - * this allows an intervening SIGCONT to be posted. - * We need to check for that and bail out if necessary. + * We must initiate one now. */ struct task_struct *t; - spin_unlock_irq(&sighand->siglock); - - /* signals can be posted during this window */ - - read_lock(&tasklist_lock); - spin_lock_irq(&sighand->siglock); + current->exit_code = signr; + sig->group_exit_code = signr; - if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) { + stop_count = 0; + for (t = next_thread(current); t != current; t = next_thread(t)) /* - * Another stop or continue happened while we - * didn't have the lock. We can just swallow this - * signal now. If we raced with a SIGCONT, that - * should have just cleared it now. If we raced - * with another processor delivering a stop signal, - * then the SIGCONT that wakes us up should clear it. + * Setting state to TASK_STOPPED for a group + * stop is always done with the siglock held, + * so this check has no races. */ - read_unlock(&tasklist_lock); - return 0; - } - - if (sig->group_stop_count == 0) { - sig->group_exit_code = signr; - stop_count = 0; - for (t = next_thread(current); t != current; - t = next_thread(t)) - /* - * Setting state to TASK_STOPPED for a group - * stop is always done with the siglock held, - * so this check has no races. - */ - if (!t->exit_state && - !(t->state & (TASK_STOPPED|TASK_TRACED))) { - stop_count++; - signal_wake_up(t, 0); - } - sig->group_stop_count = stop_count; - } - else { - /* A race with another thread while unlocked. */ - signr = sig->group_exit_code; - stop_count = --sig->group_stop_count; - } + if (!t->exit_state && + !(t->state & (TASK_STOPPED|TASK_TRACED))) { + stop_count++; + signal_wake_up(t, 0); + } + sig->group_stop_count = stop_count; - current->exit_code = signr; set_current_state(TASK_STOPPED); if (stop_count == 0) sig->flags = SIGNAL_STOP_STOPPED; - - spin_unlock_irq(&sighand->siglock); - read_unlock(&tasklist_lock); } + spin_unlock_irq(&sighand->siglock); finish_stop(stop_count); return 1; } |