From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: musb RPM sleep-while-atomic in 4.9-rc1 Date: Tue, 25 Oct 2016 10:32:37 +0200 Message-ID: <20161025083237.GF12024@localhost> References: <20161020153749.GC12413@localhost> <20161021070848.rum7wrlihjayqdbh@atomide.com> <20161021092530.GO2765@localhost> <20161021094904.q66kjsl33yzf2kir@atomide.com> <20161021110725.GA5192@localhost> <20161021112745.lancojpgv4h6aqpw@atomide.com> <20161024173538.26xvlitxiwjmh4fx@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20161024173538.26xvlitxiwjmh4fx-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tony Lindgren Cc: Johan Hovold , Bin Liu , linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-omap@vger.kernel.org On Mon, Oct 24, 2016 at 10:35:38AM -0700, Tony Lindgren wrote: > From: Tony Lindgren > Date: Mon, 24 Oct 2016 09:18:02 -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: > > [] (__might_sleep) from [] (__pm_runtime_resume+0x9c/0xa0) > [] (__pm_runtime_resume) from [] (otg_timer+0x3c/0x254) > [] (otg_timer) from [] (call_timer_fn+0xfc/0x41c) > [] (call_timer_fn) from [] (expire_timers+0x120/0x210) > [] (expire_timers) from [] (run_timer_softirq+0xa4/0xdc) > [] (run_timer_softirq) from [] (__do_softirq+0x12c/0x594) > > I did not notice that as I did not have CONFIG_DEBUG_ATOMIC_SLEEP enabled. > > Let's fix the issue by adding dsps_check_status() and dsps_runtime_resume() > functions. And let's have otg_timer() check for the PM runtime status, and > if not already enabled, have dsps_runtime_resume() call dsps_check_status() > directly. While this makes the sleeping-while-atomic warning go away, it does not seem correct. In case we were suspended, the glue layer will now call dsps_check_status while the controller (child) is still suspended: [ 8.577538] musb-hdrc musb-hdrc.0.auto: otg_timer [ 8.582642] musb-dsps 47401400.usb: dsps_runtime_resume [ 8.600651] musb-hdrc musb-hdrc.0.auto: dsps_check_status [ 8.630617] musb-hdrc musb-hdrc.0.auto: musb_runtime_resume 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