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Message-ID: <685ef627-e377-bbf1-da11-7f7556ca2dd7@collabora.com>
Date: Thu, 2 Jul 2020 19:19:32 +0200
From: Andrzej Pietrasiewicz <andrzej.p@...labora.com>
To: Daniel Lezcano <daniel.lezcano@...aro.org>,
linux-pm@...r.kernel.org, linux-acpi@...r.kernel.org,
netdev@...r.kernel.org, linux-wireless@...r.kernel.org,
platform-driver-x86@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-renesas-soc@...r.kernel.org,
linux-rockchip@...ts.infradead.org
Cc: "Rafael J . Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>,
Vishal Kulkarni <vishal@...lsio.com>,
"David S . Miller" <davem@...emloft.net>,
Jiri Pirko <jiri@...lanox.com>,
Ido Schimmel <idosch@...lanox.com>,
Johannes Berg <johannes.berg@...el.com>,
Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
Luca Coelho <luciano.coelho@...el.com>,
Intel Linux Wireless <linuxwifi@...el.com>,
Kalle Valo <kvalo@...eaurora.org>,
Peter Kaestle <peter@...e.net>,
Darren Hart <dvhart@...radead.org>,
Andy Shevchenko <andy@...radead.org>,
Sebastian Reichel <sre@...nel.org>,
Miquel Raynal <miquel.raynal@...tlin.com>,
Amit Kucheria <amit.kucheria@...durent.com>,
Support Opensource <support.opensource@...semi.com>,
Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
Fabio Estevam <festevam@...il.com>,
NXP Linux Team <linux-imx@....com>,
Niklas Söderlund <niklas.soderlund@...natech.se>,
Heiko Stuebner <heiko@...ech.de>,
Orson Zhai <orsonzhai@...il.com>,
Baolin Wang <baolin.wang7@...il.com>,
Chunyan Zhang <zhang.lyra@...il.com>,
Zhang Rui <rui.zhang@...el.com>,
Allison Randal <allison@...utok.net>,
Enrico Weigelt <info@...ux.net>,
Gayatri Kammela <gayatri.kammela@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
kernel@...labora.com
Subject: Re: [PATCH v7 00/11] Stop monitoring disabled devices
Hi,
W dniu 02.07.2020 o 19:01, Daniel Lezcano pisze:
> On 02/07/2020 15:53, Andrzej Pietrasiewicz wrote:
>> Hi Daniel,
>>
>> <snip>
>>
>>>>>>>
>>>>>>> I did reproduce:
>>>>>>>
>>>>>>> v5.8-rc3 + series => imx6 hang at boot time
>>>>>>> v5.8-rc3 => imx6 boots correctly
>>>
>>> So finally I succeeded to reproduce it on my imx7 locally. The sensor
>>> was failing to initialize for another reason related to the legacy
>>> cooling device, this is why it is not appearing on the imx7.
>>>
>>> I can now git-bisect :)
>>>
>>
>> That would be very kind of you, thank you!
>
> With the lock correctness option enabled:
>
> [ 4.179223] imx_thermal tempmon: Extended Commercial CPU temperature
> grade - max:105C critical:100C passive:95C
> [ 4.189557]
> [ 4.191060] ============================================
> [ 4.196378] WARNING: possible recursive locking detected
> [ 4.201699] 5.8.0-rc3-00011-gf5e50bf4d3ef #42 Not tainted
> [ 4.207102] --------------------------------------------
> [ 4.212421] kworker/0:3/54 is trying to acquire lock:
> [ 4.217480] ca09a3e4 (&tz->lock){+.+.}-{3:3}, at:
> thermal_zone_device_is_enabled+0x18/0x34
> [ 4.225777]
> [ 4.225777] but task is already holding lock:
> [ 4.231615] ca09a3e4 (&tz->lock){+.+.}-{3:3}, at:
> thermal_zone_get_temp+0x38/0x6c
> [ 4.239121]
> [ 4.239121] other info that might help us debug this:
> [ 4.245655] Possible unsafe locking scenario:
> [ 4.245655]
> [ 4.251579] CPU0
> [ 4.254031] ----
> [ 4.256481] lock(&tz->lock);
> [ 4.259544] lock(&tz->lock);
> [ 4.262608]
> [ 4.262608] *** DEADLOCK ***
> [ 4.262608]
> [ 4.268533] May be due to missing lock nesting notation
> [ 4.268533]
> [ 4.275329] 4 locks held by kworker/0:3/54:
> [ 4.279517] #0: cb0066a8 ((wq_completion)events){+.+.}-{0:0}, at:
> process_one_work+0x224/0x808
> [ 4.288241] #1: ca075f10 (deferred_probe_work){+.+.}-{0:0}, at:
> process_one_work+0x224/0x808
> [ 4.296787] #2: cb1a48d8 (&dev->mutex){....}-{3:3}, at:
> __device_attach+0x30/0x140
> [ 4.304468] #3: ca09a3e4 (&tz->lock){+.+.}-{3:3}, at:
> thermal_zone_get_temp+0x38/0x6c
> [ 4.312408]
> [ 4.312408] stack backtrace:
> [ 4.316778] CPU: 0 PID: 54 Comm: kworker/0:3 Not tainted
> 5.8.0-rc3-00011-gf5e50bf4d3ef #42
> [ 4.325048] Hardware name: Freescale i.MX7 Dual (Device Tree)
> [ 4.330809] Workqueue: events deferred_probe_work_func
> [ 4.335973] [<c0312384>] (unwind_backtrace) from [<c030c580>]
> (show_stack+0x10/0x14)
> [ 4.343734] [<c030c580>] (show_stack) from [<c079d7d8>]
> (dump_stack+0xe8/0x114)
> [ 4.351062] [<c079d7d8>] (dump_stack) from [<c03abf78>]
> (__lock_acquire+0xbfc/0x2cb4)
> [ 4.358909] [<c03abf78>] (__lock_acquire) from [<c03ae9c4>]
> (lock_acquire+0xf4/0x4e4)
> [ 4.366758] [<c03ae9c4>] (lock_acquire) from [<c10630fc>]
> (__mutex_lock+0xb0/0xaa8)
> [ 4.374431] [<c10630fc>] (__mutex_lock) from [<c1063b10>]
> (mutex_lock_nested+0x1c/0x24)
> [ 4.382452] [<c1063b10>] (mutex_lock_nested) from [<c0d932c0>]
> (thermal_zone_device_is_enabled+0x18/0x34)
> [ 4.392036] [<c0d932c0>] (thermal_zone_device_is_enabled) from
> [<c0d9da90>] (imx_get_temp+0x30/0x208)
> [ 4.401271] [<c0d9da90>] (imx_get_temp) from [<c0d97484>]
> (thermal_zone_get_temp+0x4c/0x6c)
> [ 4.409640] [<c0d97484>] (thermal_zone_get_temp) from [<c0d93df0>]
> (thermal_zone_device_update+0x8c/0x258)
> [ 4.419310] [<c0d93df0>] (thermal_zone_device_update) from
> [<c0d9401c>] (thermal_zone_device_set_mode+0x60/0x88)
> [ 4.429500] [<c0d9401c>] (thermal_zone_device_set_mode) from
> [<c0d9e1d4>] (imx_thermal_probe+0x3e4/0x578)
> [ 4.439082] [<c0d9e1d4>] (imx_thermal_probe) from [<c0a78388>]
> (platform_drv_probe+0x48/0x98)
> [ 4.447622] [<c0a78388>] (platform_drv_probe) from [<c0a7603c>]
> (really_probe+0x218/0x348)
> [ 4.455903] [<c0a7603c>] (really_probe) from [<c0a76278>]
> (driver_probe_device+0x5c/0xb4)
> [ 4.464098] [<c0a76278>] (driver_probe_device) from [<c0a743bc>]
> (bus_for_each_drv+0x58/0xb8)
> [ 4.472638] [<c0a743bc>] (bus_for_each_drv) from [<c0a75db0>]
> (__device_attach+0xd4/0x140)
> [ 4.480919] [<c0a75db0>] (__device_attach) from [<c0a750b0>]
> (bus_probe_device+0x88/0x90)
> [ 4.489112] [<c0a750b0>] (bus_probe_device) from [<c0a75564>]
> (deferred_probe_work_func+0x68/0x98)
> [ 4.498088] [<c0a75564>] (deferred_probe_work_func) from [<c0369988>]
> (process_one_work+0x2e0/0x808)
> [ 4.507237] [<c0369988>] (process_one_work) from [<c036a150>]
> (worker_thread+0x2a0/0x59c)
> [ 4.515432] [<c036a150>] (worker_thread) from [<c0372208>]
> (kthread+0x16c/0x178)
> [ 4.522843] [<c0372208>] (kthread) from [<c0300174>]
> (ret_from_fork+0x14/0x20)
> [ 4.530074] Exception stack(0xca075fb0 to 0xca075ff8)
> [ 4.535138] 5fa0: 00000000
> 00000000 00000000 00000000
> [ 4.543328] 5fc0: 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000 00000000
> [ 4.551516] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
>
>
>
Thanks!
That confirms your suspicions.
So the reason is that ->get_temp() is called while the mutex is held and
thermal_zone_device_is_enabled() wants to take the same mutex.
Is adding a comment to thermal_zone_device_is_enabled() to never call
it while the mutex is held and adding another version of it which does
not take the mutex ok?
Andrzej
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