Hi Guys,
I'm working on a linux gamepad implementation using libusb and it's working
great so far. Thank you for the wonderful project :)
One thing I did notice is when my gamepad gets unplugged there are
sometimes segfault generated.
At arrive callback, I call libusb_open and saved two things:
libusb_device *dev;
libusb_device_handle *dev_handle;
At left callback, I do this:
libusb_close(dev_handle);
dev = NULL;
Is setting NULL pointer a bad idea and should I just let libusb handle all
the cases? I sometimes send rumble command to the gamepad, which doesn't
actually comes from the same thread that handle_event gets called. I use
the NULL pointer
After some investigation, I have found two cases where the segfault can
happen.
1. In linux_usbfs.c in function op_handle_events():
If list_for_each_entry on ctx->open_devs never get into the loop, the
hpriv will
be NULL and usbi_remove_pollfd will trigger a segfault. A simple null check
on the hpriv will get us off this one but I'm not sure if this is desired.
2. In linux_usbfs.c in function submit_bulk_transfer
usbi_err(TRANSFER_CTX(transfer), "submiturb failed error %d errno=%d", r,
errno);
TRANSFER_CTX(transfer) refers to transfer->dev_hanlde->dev->ctx, which dev
can be either NULL if I set it or some invalid value like 0x10.
Thanks,
Kuangye
--
Kuangye (Vincent) Guo
kuangye....@gmail.com
(347)-463-4248
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