1 files changed, 16 insertions, 18 deletions

diff --git a/executor/executor.cc b/executor/executor.cc
index f0d32dcea..2635d5a7c 100644
--- a/executor/executor.cc
+++ b/executor/executor.cc
@@ -199,7 +199,6 @@ struct thread_t {
 	uint32 reserrno;
 	bool fault_injected;
 	cover_t cov;
-	bool extra_cover;
 };
 
 static thread_t threads[kMaxThreads];
@@ -288,7 +287,7 @@ struct feature_t {
 	void (*setup)();
 };
 
-static thread_t* schedule_call(int call_index, int call_num, bool colliding, uint64 copyout_index, uint64 num_args, uint64* args, uint64* pos, bool extra_cover);
+static thread_t* schedule_call(int call_index, int call_num, bool colliding, uint64 copyout_index, uint64 num_args, uint64* args, uint64* pos);
 static void handle_completion(thread_t* th);
 static void copyout_call_results(thread_t* th);
 static void write_call_output(thread_t* th, bool finished);
@@ -591,8 +590,8 @@ retry:
 	}
 
 	int call_index = 0;
-	bool prog_extra_cover = false;
 	int prog_extra_timeout = 0;
+	int prog_extra_cover_timeout = 0;
 	for (;;) {
 		uint64 call_num = read_input(&input_pos);
 		if (call_num == instr_eof)
@@ -687,14 +686,11 @@ retry:
 		// Normal syscall.
 		if (call_num >= ARRAY_SIZE(syscalls))
 			fail("invalid command number %llu", call_num);
-		bool call_extra_cover = false;
 		// call_extra_timeout must match timeout in pkg/csource/csource.go.
 		int call_extra_timeout = 0;
 		// TODO: find a way to tune timeout values.
-		if (strncmp(syscalls[call_num].name, "syz_usb", strlen("syz_usb")) == 0) {
-			prog_extra_cover = true;
-			call_extra_cover = true;
-		}
+		if (strncmp(syscalls[call_num].name, "syz_usb", strlen("syz_usb")) == 0)
+			prog_extra_cover_timeout = 500;
 		if (strncmp(syscalls[call_num].name, "syz_usb_connect", strlen("syz_usb_connect")) == 0) {
 			prog_extra_timeout = 2000;
 			call_extra_timeout = 2000;
@@ -721,7 +717,7 @@ retry:
 		for (uint64 i = num_args; i < kMaxArgs; i++)
 			args[i] = 0;
 		thread_t* th = schedule_call(call_index++, call_num, colliding, copyout_index,
-					     num_args, args, input_pos, call_extra_cover);
+					     num_args, args, input_pos);
 
 		if (colliding && (call_index % 2) == 0) {
 			// Don't wait for every other call.
@@ -779,8 +775,6 @@ retry:
 					write_call_output(th, false);
 				}
 			}
-			if (prog_extra_cover)
-				write_extra_output();
 		}
 	}
 
@@ -788,10 +782,16 @@ retry:
 	close_fds();
 #endif
 
-	if (prog_extra_cover) {
-		sleep_ms(500);
-		if (!colliding && !collide)
+	if (!colliding && !collide) {
+		write_extra_output();
+		// Check for new extra coverage in small intervals to avoid situation
+		// that we were killed on timeout before we write any.
+		// Check for extra coverage is very cheap, effectively a memory load.
+		const int kSleepMs = 100;
+		for (int i = 0; i < prog_extra_cover_timeout / kSleepMs; i++) {
+			sleep_ms(kSleepMs);
 			write_extra_output();
+		}
 	}
 
 	if (flag_collide && !flag_fault && !colliding && !collide) {
@@ -801,7 +801,7 @@ retry:
 	}
 }
 
-thread_t* schedule_call(int call_index, int call_num, bool colliding, uint64 copyout_index, uint64 num_args, uint64* args, uint64* pos, bool extra_cover)
+thread_t* schedule_call(int call_index, int call_num, bool colliding, uint64 copyout_index, uint64 num_args, uint64* args, uint64* pos)
 {
 	// Find a spare thread to execute the call.
 	int i;
@@ -832,7 +832,6 @@ thread_t* schedule_call(int call_index, int call_num, bool colliding, uint64 cop
 	th->num_args = num_args;
 	for (int i = 0; i < kMaxArgs; i++)
 		th->args[i] = args[i];
-	th->extra_cover = extra_cover;
 	event_set(&th->ready);
 	running++;
 	return th;
@@ -891,8 +890,7 @@ void handle_completion(thread_t* th)
 		copyout_call_results(th);
 	if (!collide && !th->colliding) {
 		write_call_output(th, true);
-		if (th->extra_cover)
-			write_extra_output();
+		write_extra_output();
 	}
 	th->executing = false;
 	running--;