Messages in this thread | | | Date | Thu, 2 Apr 2009 23:55:08 +0100 | From | Alan Cox <> | Subject | Re: mutex_lock_slowpath warning using mxser tty driver (input/output error) |
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On Thu, 02 Apr 2009 22:23:57 +0200 Jiri Slaby <jirislaby@gmail.com> wrote:
> On 04/02/2009 08:44 PM, Alan Cox wrote: > >> It appears to want to lock a mutex in interrupt context, something > >> that's a definite no-no. > >> > >> CCed the folks who might know a thing or two about the driver. > > > > Moxa is not a USB driver so the USB trace at the end makes no sense at > > all. > > Yes, unreliable stack entries, but echo_set_canon_col is called from irq > context and locks mutex.
Which means that either the driver is calling the ldisc receive handlers from an IRQ directly (not allowed) or calling the tty_flip_buffer_push paths and set tty->low_latency
2.6.29 is the first kernel that catches this bug with warnings.
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