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-rw-r--r--kernel/signal.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 9b04631acde8..e93de6daa188 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1308,6 +1308,43 @@ enum sig_handler {
};
/*
+ * On some archictectures, PREEMPT_RT has to delay sending a signal from a
+ * trap since it cannot enable preemption, and the signal code's
+ * spin_locks turn into mutexes. Instead, it must set TIF_NOTIFY_RESUME
+ * which will send the signal on exit of the trap.
+ */
+#ifdef CONFIG_RT_DELAYED_SIGNALS
+static inline bool force_sig_delayed(struct kernel_siginfo *info,
+ struct task_struct *t)
+{
+ if (!in_atomic())
+ return false;
+
+ if (WARN_ON_ONCE(t->forced_info.si_signo))
+ return true;
+
+ if (is_si_special(info)) {
+ WARN_ON_ONCE(info != SEND_SIG_PRIV);
+ t->forced_info.si_signo = info->si_signo;
+ t->forced_info.si_errno = 0;
+ t->forced_info.si_code = SI_KERNEL;
+ t->forced_info.si_pid = 0;
+ t->forced_info.si_uid = 0;
+ } else {
+ t->forced_info = *info;
+ }
+ set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
+ return true;
+}
+#else
+static inline bool force_sig_delayed(struct kernel_siginfo *info,
+ struct task_struct *t)
+{
+ return false;
+}
+#endif
+
+/*
* Force a signal that the process can't ignore: if necessary
* we unblock the signal and change any SIG_IGN to SIG_DFL.
*
@@ -1327,6 +1364,9 @@ force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
struct k_sigaction *action;
int sig = info->si_signo;
+ if (force_sig_delayed(info, t))
+ return 0;
+
spin_lock_irqsave(&t->sighand->siglock, flags);
action = &t->sighand->action[sig-1];
ignored = action->sa.sa_handler == SIG_IGN;