mirror of https://gitee.com/openkylin/linux.git
3611f4d2a5
Arjan: With the help of kerneloops.org I've spotted a nice little interaction between the TTY layer and the bluetooth code, however the tty layer is not something I'm all too familiar with so I rather ask than brute-force fix the code incorrectly. The raw details are at: http://www.kerneloops.org/search.php?search=uart_flush_buffer What happens is that, on closing the bluetooth tty, the tty layer goes into the release_dev() function, which first does a bunch of stuff, then sets the file->private_data to NULL, does some more stuff and then calls the ldisc close function. Which in this case, is hci_uart_tty_close(). Now, hci_uart_tty_close() calls hci_uart_close() which clears some internal bit, and then calls hci_uart_flush()... which calls back to the tty layers' uart_flush_buffer() function. (in drivers/bluetooth/hci_tty.c around line 194) Which then WARN_ON()'s because that's not allowed/supposed to be called this late in the shutdown of the port.... Should the bluetooth driver even call this flush function at all?? David: This seems to be what happens: Hci_uart_close() flushes using hci_uart_flush(). Subsequently, in hci_dev_do_close(), (one step in hci_unregister_dev()), hci_uart_flush() is called again. The comment in uart_flush_buffer(), relating to the WARN_ON(), indicates you can't flush after the port is closed; which sounds reasonable. I think hci_uart_close() should set hdev->flush to NULL before returning. Hci_dev_do_close() does check for this. The code path is rather involved and I'm not entirely clear of all steps, but I think that's what should be done. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| bcm203x.c | ||
| bfusb.c | ||
| bluecard_cs.c | ||
| bpa10x.c | ||
| bt3c_cs.c | ||
| btsdio.c | ||
| btuart_cs.c | ||
| btusb.c | ||
| dtl1_cs.c | ||
| hci_bcsp.c | ||
| hci_h4.c | ||
| hci_ldisc.c | ||
| hci_ll.c | ||
| hci_uart.h | ||
| hci_usb.c | ||
| hci_usb.h | ||
| hci_vhci.c | ||