} while_each_thread(p, t);
return;
}
-
- /*
- * There will be a core dump. We make all threads other
- * than the chosen one go into a group stop so that nothing
- * happens until it gets scheduled, takes the signal off
- * the shared queue, and does the core dump. This is a
- * little more complicated than strictly necessary, but it
- * keeps the signal state that winds up in the core dump
- * unchanged from the death state, e.g. which thread had
- * the core-dump signal unblocked.
- */
- rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
- rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
- p->signal->group_stop_count = 0;
- p->signal->group_exit_task = t;
- p = t;
- do {
- p->signal->group_stop_count++;
- signal_wake_up(t, t == p);
- } while_each_thread(p, t);
- return;
}
/*
{
struct task_struct *t;
- p->signal->flags = SIGNAL_GROUP_EXIT;
p->signal->group_stop_count = 0;
for (t = next_thread(p); t != p; t = next_thread(t)) {
return 1;
}
+/*
+ * Return nonzero if there is a SIGKILL that should be waking us up.
+ * Called with the siglock held.
+ */
+static int sigkill_pending(struct task_struct *tsk)
+{
+ return ((sigismember(&tsk->pending.signal, SIGKILL) ||
+ sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) &&
+ !unlikely(sigismember(&tsk->blocked, SIGKILL)));
+}
+
/*
* This must be called with current->sighand->siglock held.
*
*/
static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info)
{
+ int killed = 0;
+
+ if (arch_ptrace_stop_needed(exit_code, info)) {
+ /*
+ * The arch code has something special to do before a
+ * ptrace stop. This is allowed to block, e.g. for faults
+ * on user stack pages. We can't keep the siglock while
+ * calling arch_ptrace_stop, so we must release it now.
+ * To preserve proper semantics, we must do this before
+ * any signal bookkeeping like checking group_stop_count.
+ * Meanwhile, a SIGKILL could come in before we retake the
+ * siglock. That must prevent us from sleeping in TASK_TRACED.
+ * So after regaining the lock, we must check for SIGKILL.
+ */
+ spin_unlock_irq(¤t->sighand->siglock);
+ arch_ptrace_stop(exit_code, info);
+ spin_lock_irq(¤t->sighand->siglock);
+ killed = sigkill_pending(current);
+ }
+
/*
* If there is a group stop in progress,
* we must participate in the bookkeeping.
current->exit_code = exit_code;
/* Let the debugger run. */
- set_current_state(TASK_TRACED);
+ __set_current_state(TASK_TRACED);
spin_unlock_irq(¤t->sighand->siglock);
try_to_freeze();
read_lock(&tasklist_lock);
- if (may_ptrace_stop()) {
+ if (!unlikely(killed) && may_ptrace_stop()) {
do_notify_parent_cldstop(current, CLD_TRAPPED);
read_unlock(&tasklist_lock);
schedule();
struct signal_struct *sig = current->signal;
int stop_count;
- if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED))
- return 0;
-
if (sig->group_stop_count > 0) {
/*
* There is a group stop in progress. We don't need to
*/
stop_count = --sig->group_stop_count;
} else {
+ struct task_struct *t;
+
+ if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
+ unlikely(sig->group_exit_task))
+ return 0;
/*
* There is no group stop already in progress.
* We must initiate one now.
*/
- struct task_struct *t;
-
sig->group_exit_code = signr;
stop_count = 0;
return 1;
}
-/*
- * Do appropriate magic when group_stop_count > 0.
- * We return nonzero if we stopped, after releasing the siglock.
- * We return zero if we still hold the siglock and should look
- * for another signal without checking group_stop_count again.
- */
-static int handle_group_stop(void)
-{
- int stop_count;
-
- if (current->signal->group_exit_task == current) {
- /*
- * Group stop is so we can do a core dump,
- * We are the initiating thread, so get on with it.
- */
- current->signal->group_exit_task = NULL;
- return 0;
- }
-
- if (current->signal->flags & SIGNAL_GROUP_EXIT)
- /*
- * Group stop is so another thread can do a core dump,
- * or else we are racing against a death signal.
- * Just punt the stop so we can get the next signal.
- */
- return 0;
-
- /*
- * There is a group stop in progress. We stop
- * without any associated signal being in our queue.
- */
- stop_count = --current->signal->group_stop_count;
- if (stop_count == 0)
- current->signal->flags = SIGNAL_STOP_STOPPED;
- current->exit_code = current->signal->group_exit_code;
- set_current_state(TASK_STOPPED);
- spin_unlock_irq(¤t->sighand->siglock);
- finish_stop(stop_count);
- return 1;
-}
-
int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
struct pt_regs *regs, void *cookie)
{
struct k_sigaction *ka;
if (unlikely(current->signal->group_stop_count > 0) &&
- handle_group_stop())
+ do_signal_stop(0))
goto relock;
signr = dequeue_signal(current, mask, info);
projects / firefly-linux-kernel-4.4.55.git / blobdiff