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hidapi/libusb/hid.c: fix race condition on device close (bug #5484) 

From hidapi mainstream git: https://github.com/libusb/hidapi/issues/142
d2c3a9862e

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.
This commit is contained in:
Ozkan Sezer 2021-01-19 19:50:10 +03:00
parent ee93f0edee
commit 07f83cd5a6
1 changed files with 10 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
src/hidapi/libusb/hid.c
View File

@ -157,7 +157,7 @@ struct hid_device_ {
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 @@ static void LIBUSB_CALL read_callback(struct libusb_transfer *transfer)
}
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 @@ static void LIBUSB_CALL read_callback(struct libusb_transfer *transfer)
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 @@ static int read_thread(void *param)
res != LIBUSB_ERROR_TIMEOUT &&
res != LIBUSB_ERROR_OVERFLOW &&
res != LIBUSB_ERROR_INTERRUPTED) {
dev->shutdown_thread = 1;
break;
}
}
@ -895,8 +897,8 @@ static int read_thread(void *param)
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