Re: Locking problem in usbserial with 2.6.23-git 5a34417f

From: Larry Finger
Date: Fri Oct 19 2007 - 17:29:30 EST


Jiri Kosina wrote:
> On Fri, 19 Oct 2007, Larry Finger wrote:
>
>> While attempting to configure a new USB modem, the following locking
>> problem occurred. In addition, shortly after this problem occurred, the
>> computer froze. The log data starts at the point that usbserial was
>> loaded and contains everything that was written to disk before the
>> machine locked up. Some info may be missing from the end of the stack
>> dump.
>
> I guess this one is needed.
>
>
> From: Jiri Kosina <jkosina@xxxxxxx>
>
> USB: usbserial - fix potential deadlock between write() and irq
>
> usb_serial_generic_write() doesn't disable interrupts when taking port->lock,
> and could therefore deadlock with usb_serial_generic_read_bulk_callback()
> being called from interrupt, taking the same lock. Fix it.
>
> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
>

Yes, this patch did fix the locking problem.

Thanks,

Larry
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