Re: [PATCH 2/4] usb: musb: Fix sleeping function called from invalid context for hdrc glue

[Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Fri, Nov 11, 2016 at 07:42:50AM -0800, Tony Lindgren wrote:
> * Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> [161111 04:03]:
> > On Thu, Nov 10, 2016 at 12:40:03PM -0700, Tony Lindgren wrote:

> From tony Mon Sep 17 00:00:00 2001
> From: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
> Date: Wed, 2 Nov 2016 19:59:05 -0700
> Subject: [PATCH] usb: musb: Fix sleeping function called from invalid
>  context for hdrc glue
> 
> Commit 65b3f50ed6fa ("usb: musb: Add PM runtime support for MUSB DSPS
> glue layer") wrongly added a call for pm_runtime_get_sync to otg_timer
> that runs in softirq context. That causes a "BUG: sleeping function called
> from invalid context" every time when polling the cable status:
> 
> [<c015ebb4>] (__might_sleep) from [<c0413d60>] (__pm_runtime_resume+0x9c/0xa0)
> [<c0413d60>] (__pm_runtime_resume) from [<c04d0bc4>] (otg_timer+0x3c/0x254)
> [<c04d0bc4>] (otg_timer) from [<c0191180>] (call_timer_fn+0xfc/0x41c)
> [<c0191180>] (call_timer_fn) from [<c01915c0>] (expire_timers+0x120/0x210)
> [<c01915c0>] (expire_timers) from [<c0191acc>] (run_timer_softirq+0xa4/0xdc)
> [<c0191acc>] (run_timer_softirq) from [<c010168c>] (__do_softirq+0x12c/0x594)
> 
> I did not notice that as I did not have CONFIG_DEBUG_ATOMIC_SLEEP enabled.
> And looks like also musb_gadget_queue() suffers from the same problem.
> 
> Let's fix the issue by using a list of delayed work then call it on
> resume. Note that we want to do this only when musb core and it's
> parent devices are awake, and we need to make sure the DSPS glue
> timer is stopped as noted by Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>.
> Note that we already are re-enabling the timer with mod_timer() in
> dsps_musb_enable().
> 
> Later on we may be able to remove other delayed work in the musb driver
> and just do it from pending_resume_work. But this should be done only
> for delayed work that does not have other timing requirements beyond
> just being run on resume.
> 
> Fixes: 65b3f50ed6fa ("usb: musb: Add PM runtime support for MUSB DSPS
> glue layer")
> Reported-by: Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Signed-off-by: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>

Looks good to me now. Feel free to add

Reviewed-by: Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

Thanks,
Johan
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html