hidapi/libusb/hid.c: fix race condition on device close (bug #5484)
From hidapi mainstream git: https://github.com/libusb/hidapi/issues/142
https://github.com/libusb/hidapi/commit/d2c3a9862eefe2d3f4db0f00c0238277bfb4e44b
Read callback may fire itself on its own even after its been requested
to stop and exactly before the calling code waits for its completion in
indefinite loop. Explicitly preventing re-fireing the submission loop
fixes the issue.
diff --git a/src/hidapi/libusb/hid.c b/src/hidapi/libusb/hid.c
index 8fa98b0..0ba007e 100644
--- a/src/hidapi/libusb/hid.c
+++ b/src/hidapi/libusb/hid.c
@@ -157,7 +157,7 @@
SDL_cond *condition;
SDL_ThreadBarrier barrier; /* Ensures correct startup sequence */
int shutdown_thread;
- int cancelled;
+ int transfer_loop_finished;
struct libusb_transfer *transfer;
/* List of received input reports. */
@@ -823,13 +823,9 @@
}
else if (transfer->status == LIBUSB_TRANSFER_CANCELLED) {
dev->shutdown_thread = 1;
- dev->cancelled = 1;
- return;
}
else if (transfer->status == LIBUSB_TRANSFER_NO_DEVICE) {
dev->shutdown_thread = 1;
- dev->cancelled = 1;
- return;
}
else if (transfer->status == LIBUSB_TRANSFER_TIMED_OUT) {
//LOG("Timeout (normal)\n");
@@ -838,12 +834,17 @@
LOG("Unknown transfer code: %d\n", transfer->status);
}
+ if (dev->shutdown_thread) {
+ dev->transfer_loop_finished = 1;
+ return;
+ }
+
/* Re-submit the transfer object. */
res = libusb_submit_transfer(transfer);
if (res != 0) {
LOG("Unable to submit URB. libusb error code: %d\n", res);
dev->shutdown_thread = 1;
- dev->cancelled = 1;
+ dev->transfer_loop_finished = 1;
}
}
@@ -886,6 +887,7 @@
res != LIBUSB_ERROR_TIMEOUT &&
res != LIBUSB_ERROR_OVERFLOW &&
res != LIBUSB_ERROR_INTERRUPTED) {
+ dev->shutdown_thread = 1;
break;
}
}
@@ -895,8 +897,8 @@
if no transfers are pending, but that's OK. */
libusb_cancel_transfer(dev->transfer);
- while (!dev->cancelled)
- libusb_handle_events_completed(usb_context, &dev->cancelled);
+ while (!dev->transfer_loop_finished)
+ libusb_handle_events_completed(usb_context, &dev->transfer_loop_finished);
/* Now that the read thread is stopping, Wake any threads which are
waiting on data (in hid_read_timeout()). Do this under a mutex to
