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Message-ID: <CAGETcx9xjyPw01gmhtu9XShmkmXriTPgoc8UfSQgHhkQg5S=VQ@mail.gmail.com>
Date: Wed, 22 Jul 2020 08:25:32 -0700
From: Saravana Kannan <saravanak@...gle.com>
To: paulmck@...nel.org
Cc: Arnd Bergmann <arnd@...db.de>,
Naresh Kamboju <naresh.kamboju@...aro.org>,
open list <linux-kernel@...r.kernel.org>, rcu@...r.kernel.org,
Linux-Next Mailing List <linux-next@...r.kernel.org>,
lkft-triage@...ts.linaro.org,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
Josh Triplett <josh@...htriplett.org>,
Steven Rostedt <rostedt@...dmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Lai Jiangshan <jiangshanlai@...il.com>,
Joel Fernandes <joel@...lfernandes.org>,
Stephen Rothwell <sfr@...b.auug.org.au>,
walter-zh.wu@...iatek.com, neeraju@...eaurora.org,
Vinod Koul <vinod.koul@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: BUG: sleeping function called from invalid context at
kernel/locking/mutex.c db410c
On Wed, Jul 22, 2020 at 6:01 AM Paul E. McKenney <paulmck@...nel.org> wrote:
>
> On Wed, Jul 22, 2020 at 10:04:21AM +0200, Arnd Bergmann wrote:
> > On Wed, Jul 22, 2020 at 9:44 AM Naresh Kamboju
> > <naresh.kamboju@...aro.org> wrote:
> > >
> > > Kernel BUG noticed on arm64 db410c device while booting linux next 20200721 tag.
> > > Continually popping up these BUG messages on the boot console and kernel warning
> > > also noticed.
> > >
> > > metadata:
> > > git branch: master
> > > git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> > > git commit: de2e69cfe54a8f2ed4b75f09d3110c514f45d38e
> > > git describe: next-20200721
> > > kernel-config:
> > > http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/dragonboard-410c/lkft/linux-next/818/config
> > > build-location:
> > > http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/dragonboard-410c/lkft/linux-next/818
> > >
> > > Crash log:
> > > [ 0.444349] BUG: sleeping function called from invalid context at
> > > /usr/src/kernel/kernel/locking/mutex.c:935
> > > [ 0.444422] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid:
> > > 30, name: kworker/0:1
> > > [ 0.444458] 2 locks held by kworker/0:1/30:
> > > [ 0.444489] #0: ffff00000eb15138
> > > ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x208/0x768
> > > [ 0.444627] #1: ffff800013713df0
> > > ((work_completion)(&sdp->work)){+.+.}-{0:0}, at:
> > > process_one_work+0x208/0x768
> > > [ 0.444761] CPU: 0 PID: 30 Comm: kworker/0:1 Not tainted
> > > 5.8.0-rc6-next-20200721 #1
> > > [ 0.444787] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
> > > [ 0.444817] Workqueue: rcu_gp srcu_invoke_callbacks
> > > [ 0.444856] Call trace:
> > > [ 0.444883] dump_backtrace+0x0/0x1f8
> > > [ 0.444910] show_stack+0x2c/0x38
> > > [ 0.444939] dump_stack+0xf0/0x16c
> > > [ 0.444969] ___might_sleep+0x144/0x208
> > > [ 0.444996] __might_sleep+0x54/0x90
> > > [ 0.445027] __mutex_lock+0x64/0x970
> > > [ 0.445055] mutex_lock_nested+0x54/0x70
> > > [ 0.445084] device_del+0x44/0x3c0
> > > [ 0.445110] device_unregister+0x24/0x78
> > > [ 0.445138] __device_link_free_srcu+0x64/0x70
> > > [ 0.445164] srcu_invoke_callbacks+0x10c/0x1a0
> >
> > The device_unregister() was added to __device_link_free_srcu() as part
> > of commit 287905e68dd2 ("driver core: Expose device link details in sysfs")
> >
> > I'm fairly sure this is what introduced the console output, though the
> > code before it is already suspicious:
> >
> > call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
> >
> > According to the documentation, call_srcu() must not call any sleeping
> > functions, which is what the 'in_atomic(): 1' above is about.
>
> Yes, the callback function, in this case __device_link_free_srcu(),
> will execute from softirq context.
>
> > However, from what I can tell, the put_device() and pm_runtime_put()
> > calls in device_link_free() can also potentially sleep even if they normally
> > don't warn about that.
>
> The usual workaround is to have __device_link_free_srcu() schedule a
> workqueue that invokes the potentially sleeping functions.
>
> Thanx, Paul
Thanks for reporting. It was already reported and fixed last week.
Waiting on Greg to pull it in.
https://lore.kernel.org/lkml/CAGETcx9quqtV9TeD8WEcLLijGeV+7hXqnyiMv7F8xo+vyF_7iw@mail.gmail.com/#t
-Saravana
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