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-rw-r--r--kernel/signal.c38
1 files changed, 35 insertions, 3 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 589292f38530..06177e2b3917 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -817,6 +817,30 @@ static int check_kill_permission(int sig, struct siginfo *info,
return security_task_kill(t, info, sig, 0);
}
+/**
+ * ptrace_trap_notify - schedule trap to notify ptracer
+ * @t: tracee wanting to notify tracer
+ *
+ * This function schedules sticky ptrace trap which is cleared on the next
+ * TRAP_STOP to notify ptracer of an event. @t must have been seized by
+ * ptracer.
+ *
+ * If @t is running, STOP trap will be taken. If already trapped, STOP
+ * trap will be eventually taken without returning to userland after the
+ * existing traps are finished by PTRACE_CONT.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+static void ptrace_trap_notify(struct task_struct *t)
+{
+ WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
+ assert_spin_locked(&t->sighand->siglock);
+
+ task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
+ signal_wake_up(t, 0);
+}
+
/*
* Handle magic process-wide effects of stop/continue signals. Unlike
* the signal actions, these happen immediately at signal-generation
@@ -855,7 +879,10 @@ static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns)
do {
task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
- wake_up_state(t, __TASK_STOPPED);
+ if (likely(!(t->ptrace & PT_SEIZED)))
+ wake_up_state(t, __TASK_STOPPED);
+ else
+ ptrace_trap_notify(t);
} while_each_thread(p, t);
/*
@@ -1797,8 +1824,10 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
gstop_done = task_participate_group_stop(current);
- /* any trap clears pending STOP trap */
+ /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
+ if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
+ task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
/* entering a trap, clear TRAPPING */
task_clear_jobctl_trapping(current);
@@ -1972,7 +2001,10 @@ static bool do_signal_stop(int signr)
if (!task_is_stopped(t) &&
task_set_jobctl_pending(t, signr | gstop)) {
sig->group_stop_count++;
- signal_wake_up(t, 0);
+ if (likely(!(t->ptrace & PT_SEIZED)))
+ signal_wake_up(t, 0);
+ else
+ ptrace_trap_notify(t);
}
}
}