1 files changed, 48 insertions, 72 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index e93de6daa188..e43bc2a692f5 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -32,7 +32,7 @@
 #include <linux/signal.h>
 #include <linux/signalfd.h>
 #include <linux/ratelimit.h>
-#include <linux/tracehook.h>
+#include <linux/task_work.h>
 #include <linux/capability.h>
 #include <linux/freezer.h>
 #include <linux/pid_namespace.h>
@@ -1308,43 +1308,6 @@ 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.
  *
@@ -1364,9 +1327,6 @@ 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;
@@ -1845,7 +1805,7 @@ int force_sig_pkuerr(void __user *addr, u32 pkey)
 }
 #endif
 
-int force_sig_perf(void __user *addr, u32 type, u64 sig_data)
+int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
 {
 	struct kernel_siginfo info;
 
@@ -1857,7 +1817,18 @@ int force_sig_perf(void __user *addr, u32 type, u64 sig_data)
 	info.si_perf_data = sig_data;
 	info.si_perf_type = type;
 
-	return force_sig_info(&info);
+	/*
+	 * Signals generated by perf events should not terminate the whole
+	 * process if SIGTRAP is blocked, however, delivering the signal
+	 * asynchronously is better than not delivering at all. But tell user
+	 * space if the signal was asynchronous, so it can clearly be
+	 * distinguished from normal synchronous ones.
+	 */
+	info.si_perf_flags = sigismember(&current->blocked, info.si_signo) ?
+				     TRAP_PERF_FLAG_ASYNC :
+				     0;
+
+	return send_sig_info(info.si_signo, &info, current);
 }
 
 /**
@@ -2229,14 +2200,17 @@ static void do_notify_parent_cldstop(struct task_struct *tsk,
  * That makes it a way to test a stopped process for
  * being ptrace-stopped vs being job-control-stopped.
  *
- * If we actually decide not to stop at all because the tracer
- * is gone, we keep current->exit_code unless clear_code.
+ * Returns the signal the ptracer requested the code resume
+ * with.  If the code did not stop because the tracer is gone,
+ * the stop signal remains unchanged unless clear_code.
  */
-static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
+static int ptrace_stop(int exit_code, int why, int clear_code,
+			unsigned long message, kernel_siginfo_t *info)
 	__releases(&current->sighand->siglock)
 	__acquires(&current->sighand->siglock)
 {
 	bool gstop_done = false;
+	bool read_code = true;
 
 	if (arch_ptrace_stop_needed()) {
 		/*
@@ -2278,6 +2252,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
 	 */
 	smp_wmb();
 
+	current->ptrace_message = message;
 	current->last_siginfo = info;
 	current->exit_code = exit_code;
 
@@ -2344,8 +2319,9 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
 
 		/* tasklist protects us from ptrace_freeze_traced() */
 		__set_current_state(TASK_RUNNING);
+		read_code = false;
 		if (clear_code)
-			current->exit_code = 0;
+			exit_code = 0;
 		read_unlock(&tasklist_lock);
 	}
 
@@ -2355,7 +2331,11 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
 	 * any signal-sending on another CPU that wants to examine it.
 	 */
 	spin_lock_irq(&current->sighand->siglock);
+	if (read_code)
+		exit_code = current->exit_code;
 	current->last_siginfo = NULL;
+	current->ptrace_message = 0;
+	current->exit_code = 0;
 
 	/* LISTENING can be set only during STOP traps, clear it */
 	current->jobctl &= ~JOBCTL_LISTENING;
@@ -2366,9 +2346,10 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
 	 * This sets TIF_SIGPENDING, but never clears it.
 	 */
 	recalc_sigpending_tsk(current);
+	return exit_code;
 }
 
-static void ptrace_do_notify(int signr, int exit_code, int why)
+static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message)
 {
 	kernel_siginfo_t info;
 
@@ -2379,18 +2360,21 @@ static void ptrace_do_notify(int signr, int exit_code, int why)
 	info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
 
 	/* Let the debugger run.  */
-	ptrace_stop(exit_code, why, 1, &info);
+	return ptrace_stop(exit_code, why, 1, message, &info);
 }
 
-void ptrace_notify(int exit_code)
+int ptrace_notify(int exit_code, unsigned long message)
 {
+	int signr;
+
 	BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
-	if (unlikely(current->task_works))
+	if (unlikely(task_work_pending(current)))
 		task_work_run();
 
 	spin_lock_irq(&current->sighand->siglock);
-	ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
+	signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message);
 	spin_unlock_irq(&current->sighand->siglock);
+	return signr;
 }
 
 /**
@@ -2545,11 +2529,10 @@ static void do_jobctl_trap(void)
 			signr = SIGTRAP;
 		WARN_ON_ONCE(!signr);
 		ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
-				 CLD_STOPPED);
+				 CLD_STOPPED, 0);
 	} else {
 		WARN_ON_ONCE(!signr);
-		ptrace_stop(signr, CLD_STOPPED, 0, NULL);
-		current->exit_code = 0;
+		ptrace_stop(signr, CLD_STOPPED, 0, 0, NULL);
 	}
 }
 
@@ -2602,15 +2585,12 @@ static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type)
 	 * comment in dequeue_signal().
 	 */
 	current->jobctl |= JOBCTL_STOP_DEQUEUED;
-	ptrace_stop(signr, CLD_TRAPPED, 0, info);
+	signr = ptrace_stop(signr, CLD_TRAPPED, 0, 0, info);
 
 	/* We're back.  Did the debugger cancel the sig?  */
-	signr = current->exit_code;
 	if (signr == 0)
 		return signr;
 
-	current->exit_code = 0;
-
 	/*
 	 * Update the siginfo structure if the signal has
 	 * changed.  If the debugger wanted something
@@ -2667,20 +2647,12 @@ bool get_signal(struct ksignal *ksig)
 	struct signal_struct *signal = current->signal;
 	int signr;
 
-	if (unlikely(current->task_works))
+	clear_notify_signal();
+	if (unlikely(task_work_pending(current)))
 		task_work_run();
 
-	/*
-	 * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so
-	 * that the arch handlers don't all have to do it. If we get here
-	 * without TIF_SIGPENDING, just exit after running signal work.
-	 */
-	if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) {
-		if (test_thread_flag(TIF_NOTIFY_SIGNAL))
-			tracehook_notify_signal();
-		if (!task_sigpending(current))
-			return false;
-	}
+	if (!task_sigpending(current))
+		return false;
 
 	if (unlikely(uprobe_deny_signal()))
 		return false;
@@ -2939,7 +2911,8 @@ static void signal_delivered(struct ksignal *ksig, int stepping)
 	set_current_blocked(&blocked);
 	if (current->sas_ss_flags & SS_AUTODISARM)
 		sas_ss_reset(current);
-	tracehook_signal_handler(stepping);
+	if (stepping)
+		ptrace_notify(SIGTRAP, 0);
 }
 
 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
@@ -3470,6 +3443,7 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
 		to->si_addr = ptr_to_compat(from->si_addr);
 		to->si_perf_data = from->si_perf_data;
 		to->si_perf_type = from->si_perf_type;
+		to->si_perf_flags = from->si_perf_flags;
 		break;
 	case SIL_CHLD:
 		to->si_pid = from->si_pid;
@@ -3547,6 +3521,7 @@ static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
 		to->si_addr = compat_ptr(from->si_addr);
 		to->si_perf_data = from->si_perf_data;
 		to->si_perf_type = from->si_perf_type;
+		to->si_perf_flags = from->si_perf_flags;
 		break;
 	case SIL_CHLD:
 		to->si_pid    = from->si_pid;
@@ -4760,6 +4735,7 @@ static inline void siginfo_buildtime_checks(void)
 	CHECK_OFFSET(si_pkey);
 	CHECK_OFFSET(si_perf_data);
 	CHECK_OFFSET(si_perf_type);
+	CHECK_OFFSET(si_perf_flags);
 
 	/* sigpoll */
 	CHECK_OFFSET(si_band);