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SubjectRe: w1: 3.14-rc7 - possible recursive locking detected
From
Hi,

On Mon, Mar 24, 2014 at 1:01 PM, Evgeniy Polyakov <zbr@ioremap.net> wrote:
> Hi everyone
>
> 24.03.2014, 01:50, "David Fries" <David@Fries.net>:
>> On Mon, Mar 17, 2014 at 10:38:13PM +0100, Belisko Marek wrote:
>>> booting latest 3.14-rc7 on gta04 board gives following warning:
>>>
>>> [ 3.101409] Driver for 1-wire Dallas network protocol.
>>> [ 3.109649] omap_hdq omap_hdq: OMAP HDQ Hardware Rev 0.5. Driver in
>>> [ 3.400146] CPU0
>>> [ 3.402709] ----
>>> [ 3.405273] lock(&(&priv->bus_notifier)->rwsem);
>>> [ 3.410308] lock(&(&priv->bus_notifier)->rwsem);
>>> [ 3.415374]
>>> [ 3.415374] *** DEADLOCK ***
>>>
>>> AFAIK we didn't see that on (at least 3/14-rc2).
>>
>> The last drivers/w1 change went in before v3.14-rc1, so if it is
>> something in the w1 code, it has either been there or something else
>> in the rest of the kernel changed to expose it. I'm using the ds2490
>> USB w1 dongle, I didn't see that problem when enabling lock debugging
>> on 3.14.0-rc5+ which includes some changes I'm working on.
>>
>> https://github.com/dfries/linux.git w1_rework
>
> Can it be a bug in omap w1 driver?
We test with actual Linus master and it's even worse (it hangs completely).
Trace look little bit different and it only happens when booting via
device tree (not with board file).

[ 2.807434] Driver for 1-wire Dallas network protocol.
[ 2.814117] omap_hdq omap_hdq: OMAP HDQ Hardware Rev 0.5. Driver in
Interrupt mode
[ 3.034271] call_modprobe: w1-family-0x1
[ 3.051818]
[ 3.053405] =============================================
[ 3.059051] [ INFO: possible recursive locking detected ]
[ 3.064727] 3.14.0-gta04 #556 Not tainted
[ 3.068939] ---------------------------------------------
[ 3.074615] w1_bus_master1/795 is trying to acquire lock:
[ 3.080261] (&(&priv->bus_notifier)->rwsem){.+.+.+}, at:
[<c0058ab0>] __blocking_notifier_call_chain+0x28/0x58
[ 3.090911]
[ 3.090911] but task is already holding lock:
[ 3.097045] (&(&priv->bus_notifier)->rwsem){.+.+.+}, at:
[<c0058ab0>] __blocking_notifier_call_chain+0x28/0x58
[ 3.107666]
[ 3.107666] other info that might help us debug this:
[ 3.114501] Possible unsafe locking scenario:
[ 3.114501]
[ 3.120727] CPU0
[ 3.123291] ----
[ 3.125854] lock(&(&priv->bus_notifier)->rwsem);
[ 3.130889] lock(&(&priv->bus_notifier)->rwsem);
[ 3.135925]
[ 3.135925] *** DEADLOCK ***
[ 3.135925]
[ 3.142150] May be due to missing lock nesting notation
[ 3.142150]
[ 3.149291] 2 locks held by w1_bus_master1/795:
[ 3.154052] #0: (&dev->mutex#3){+.+.+.}, at: [<c03ba1c8>]
w1_attach_slave_device+0xc4/0x1c8
[ 3.163055] #1: (&(&priv->bus_notifier)->rwsem){.+.+.+}, at:
[<c0058ab0>] __blocking_notifier_call_chain+0x28/0x58
[ 3.174163]
[ 3.174163] stack backtrace:
[ 3.178741] CPU: 0 PID: 795 Comm: w1_bus_master1 Not tainted
3.14.0-gta04 #556
[ 3.186370] [<c0013ca0>] (unwind_backtrace) from [<c0010f68>]
(show_stack+0x10/0x14)
[ 3.194488] [<c0010f68>] (show_stack) from [<c04f0900>]
(dump_stack+0x6c/0x88)
[ 3.202117] [<c04f0900>] (dump_stack) from [<c00746bc>]
(print_deadlock_bug+0xc0/0xf0)
[ 3.210449] [<c00746bc>] (print_deadlock_bug) from [<c0075f80>]
(validate_chain.isra.29+0x4dc/0x534)
[ 3.220031] [<c0075f80>] (validate_chain.isra.29) from [<c0076dac>]
(__lock_acquire+0x728/0x834)
[ 3.229248] [<c0076dac>] (__lock_acquire) from [<c00774b8>]
(lock_acquire+0xf4/0x118)
[ 3.237487] [<c00774b8>] (lock_acquire) from [<c04f8e04>]
(down_read+0x24/0x34)
[ 3.245178] [<c04f8e04>] (down_read) from [<c0058ab0>]
(__blocking_notifier_call_chain+0x28/0x58)
[ 3.254516] [<c0058ab0>] (__blocking_notifier_call_chain) from
[<c0058af4>] (blocking_notifier_call_chain+0x14/0x18)
[ 3.265563] [<c0058af4>] (blocking_notifier_call_chain) from
[<c0301db8>] (device_add+0x1f4/0x368)
[ 3.274993] [<c0301db8>] (device_add) from [<c03055cc>]
(platform_device_add+0x138/0x1c8)
[ 3.283569] [<c03055cc>] (platform_device_add) from [<c03bd124>]
(w1_bq27000_add_slave+0x44/0x74)
[ 3.292907] [<c03bd124>] (w1_bq27000_add_slave) from [<c03b9ed8>]
(w1_bus_notify.part.0+0x48/0xc8)
[ 3.302337] [<c03b9ed8>] (w1_bus_notify.part.0) from [<c04fbe1c>]
(notifier_call_chain+0x38/0x68)
[ 3.311645] [<c04fbe1c>] (notifier_call_chain) from [<c0058acc>]
(__blocking_notifier_call_chain+0x44/0x58)
[ 3.321899] [<c0058acc>] (__blocking_notifier_call_chain) from
[<c0058af4>] (blocking_notifier_call_chain+0x14/0x18)
[ 3.332946] [<c0058af4>] (blocking_notifier_call_chain) from
[<c0301db8>] (device_add+0x1f4/0x368)
[ 3.342346] [<c0301db8>] (device_add) from [<c03b9ad0>]
(__w1_attach_slave_device+0x9c/0x134)
[ 3.351318] [<c03b9ad0>] (__w1_attach_slave_device) from
[<c03ba238>] (w1_attach_slave_device+0x134/0x1c8)
[ 3.361480] [<c03ba238>] (w1_attach_slave_device) from [<c03ba348>]
(w1_slave_found+0x7c/0x98)
[ 3.370513] [<c03ba348>] (w1_slave_found) from [<c03bc818>]
(omap_w1_search_bus+0x54/0x5c)
[ 3.379211] [<c03bc818>] (omap_w1_search_bus) from [<c03bc758>]
(w1_search_devices+0x3c/0x48)
[ 3.388153] [<c03bc758>] (w1_search_devices) from [<c03baaec>]
(w1_search_process_cb+0x64/0x108)
[ 3.397399] [<c03baaec>] (w1_search_process_cb) from [<c03bac60>]
(w1_process+0x68/0x14c)
[ 3.405975] [<c03bac60>] (w1_process) from [<c0054bdc>] (kthread+0xdc/0xf0)
[ 3.413299] [<c0054bdc>] (kthread) from [<c000dca8>]
(ret_from_fork+0x14/0x2c)
[ 24.451049] INFO: rcu_sched detected stalls on CPUs/tasks: {}
(detected by 0, t=2102 jiffies, g=4294967086, c=4294967085, q=19)
[ 24.463134] INFO: Stall ended before state dump start
[ 87.501037] INFO: rcu_sched detected stalls on CPUs/tasks: {}
(detected by 0, t=8407 jiffies, g=4294967086, c=4294967085, q=19)
[ 87.513122] INFO: Stall ended before state dump start
[ 150.551055] INFO: rcu_sched detected stalls on CPUs/tasks: {}
(detected by 0, t=14712 jiffies, g=4294967086, c=4294967085, q=19)
[ 150.563232] INFO: Stall ended before state dump start
[ 213.601043] INFO: rcu_sched detected stalls on CPUs/tasks: {}
(detected by 0, t=21017 jiffies, g=4294967086, c=4294967085, q=19)
[ 213.613220] INFO: Stall ended before state dump start
[ 276.651062] INFO: rcu_sched detected stalls on CPUs/tasks: {}
(detected by 0, t=27322 jiffies, g=4294967086, c=4294967085, q=19)
[ 276.663238] INFO: Stall ended before state dump start

BR,

marek

--
as simple and primitive as possible
-------------------------------------------------
Marek Belisko - OPEN-NANDRA
Freelance Developer

Ruska Nova Ves 219 | Presov, 08005 Slovak Republic
Tel: +421 915 052 184
skype: marekwhite
twitter: #opennandra
web: http://open-nandra.com


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