Re: [PATCH 4.19 00/24] 4.19.176-rc1 review

[Naresh Kamboju]

On Thu, 11 Feb 2021 at 20:36, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> This is the start of the stable review cycle for the 4.19.176 release.
> There are 24 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Sat, 13 Feb 2021 15:01:39 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
>         https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.19.176-rc1.gz
> or in the git tree and branch at:
>         git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.19.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h

The following lockdep noticed on the arm beaglebone x15 device.
I have not bisected this problem yet.
Suspecting this patch,

> David Collins <collinsd@xxxxxxxxxxxxxx>
>     regulator: core: avoid regulator_resolve_supply() race condition


[    2.470568] WARNING: possible recursive locking detected
[    2.470580] 4.19.176-rc1 #1 Not tainted
[    2.470590] --------------------------------------------
[    2.470600] swapper/0/1 is trying to acquire lock:
[    2.470611] (ptrval) (&rdev->mutex){+.+.}, at: regulator_enable+0x44/0x20c
[    2.470639]
[    2.470639] but task is already holding lock:
[    2.470650] (ptrval) (&rdev->mutex){+.+.}, at:
regulator_lock_nested+0x28/0x88
[    2.470676]
[    2.470676] other info that might help us debug this:
[    2.470687]  Possible unsafe locking scenario:
[    2.470687]
[    2.470698]        CPU0
[    2.470707]        ----
[    2.470716]   lock(&rdev->mutex);
[    2.470728]   lock(&rdev->mutex);
[    2.470740]
[    2.470740]  *** DEADLOCK ***
[    2.470740]
[    2.470752]  May be due to missing lock nesting notation
[    2.470752]
[    2.470765] 2 locks held by swapper/0/1:
[    2.470774]  #0: (ptrval) (&dev->mutex){....}, at: __driver_attach+0x78/0x168
[    2.470797]  #1: (ptrval) (&rdev->mutex){+.+.}, at:
regulator_lock_nested+0x28/0x88
[    2.470820]
[    2.470820] stack backtrace:
[    2.470836] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.19.176-rc1 #1
[    2.470846] Hardware name: Generic DRA74X (Flattened Device Tree)
[    2.470871] [<c0416430>] (unwind_backtrace) from [<c040f920>]
(show_stack+0x20/0x24)
[    2.470891] [<c040f920>] (show_stack) from [<c1306bec>]
(dump_stack+0xe8/0x114)
[    2.470910] [<c1306bec>] (dump_stack) from [<c04c2a04>]
(__lock_acquire+0x7cc/0x1acc)
[    2.470925] [<c04c2a04>] (__lock_acquire) from [<c04c46ec>]
(lock_acquire+0xdc/0x238)
[    2.470941] [<c04c46ec>] (lock_acquire) from [<c130a008>]
(__mutex_lock+0xa0/0xaf4)
[    2.470958] [<c130a008>] (__mutex_lock) from [<c130aa88>]
(mutex_lock_nested+0x2c/0x34)
[    2.470974] [<c130aa88>] (mutex_lock_nested) from [<c0ae9434>]
(regulator_enable+0x44/0x20c)
[    2.470990] [<c0ae9434>] (regulator_enable) from [<c0ae9780>]
(regulator_resolve_supply+0x184/0x2c8)
[    2.471006] [<c0ae9780>] (regulator_resolve_supply) from
[<c0ae98e8>] (regulator_register_resolve_supply+0x24/0x8c)
[    2.471022] [<c0ae98e8>] (regulator_register_resolve_supply) from
[<c0c294f0>] (class_for_each_device+0x70/0xe8)
[    2.471037] [<c0c294f0>] (class_for_each_device) from [<c0aea368>]
(regulator_register+0xa18/0xc58)
[    2.471053] [<c0aea368>] (regulator_register) from [<c0aebd64>]
(devm_regulator_register+0x54/0x84)
[    2.471069] [<c0aebd64>] (devm_regulator_register) from
[<c0af8c28>] (pbias_regulator_probe+0x1f4/0x2d0)
[    2.471084] [<c0af8c28>] (pbias_regulator_probe) from [<c0c29da0>]
(platform_drv_probe+0x58/0xa8)
[    2.471101] [<c0c29da0>] (platform_drv_probe) from [<c0c273b8>]
(really_probe+0x310/0x418)
[    2.471119] [<c0c273b8>] (really_probe) from [<c0c276e4>]
(driver_probe_device+0x88/0x1dc)
[    2.471135] [<c0c276e4>] (driver_probe_device) from [<c0c27984>]
(__driver_attach+0x14c/0x168)
[    2.471150] [<c0c27984>] (__driver_attach) from [<c0c24e08>]
(bus_for_each_dev+0x84/0xc4)
[    2.471167] [<c0c24e08>] (bus_for_each_dev) from [<c0c26a18>]
(driver_attach+0x2c/0x30)
[    2.471184] [<c0c26a18>] (driver_attach) from [<c0c26380>]
(bus_add_driver+0x1d0/0x274)
[    2.471199] [<c0c26380>] (bus_add_driver) from [<c0c28a4c>]
(driver_register+0x84/0x118)
[    2.471213] [<c0c28a4c>] (driver_register) from [<c0c29cf0>]
(__platform_driver_register+0x50/0x58)
[    2.471231] [<c0c29cf0>] (__platform_driver_register) from
[<c1ca3174>] (pbias_regulator_driver_init+0x24/0x28)
[    2.471249] [<c1ca3174>] (pbias_regulator_driver_init) from
[<c0403a68>] (do_one_initcall+0xa0/0x394)
[    2.471268] [<c0403a68>] (do_one_initcall) from [<c1c01454>]
(kernel_init_freeable+0x3ec/0x484)
[    2.471283] [<c1c01454>] (kernel_init_freeable) from [<c1306ff4>]
(kernel_init+0x18/0x128)
[    2.471299] [<c1306ff4>] (kernel_init) from [<c04010ac>]
(ret_from_fork+0x14/0x28)
[    2.471310] Exception stack(0xee19bfb0 to 0xee19bff8)
[    2.471323] bfa0:                                     00000000
00000000 00000000 00000000
[    2.471336] bfc0: 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000
[    2.471348] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    2.471385] vtt_fixed: supplied by smps3

test log link,
https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-4.19.y/build/v4.19.175-25-g30e16c3fd5ac/testrun/3938030/suite/linux-log-parser/test/check-kernel-warning-2263196/log

metadata:
  git branch: linux-4.19.y
  git repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
  git commit: 30e16c3fd5acd42264d873aacb75891f3cd202c4
  git describe: v4.19.175-25-g30e16c3fd5ac
  make_kernelversion: 4.19.176-rc1
  kernel-config:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/am57xx-evm/lkft/linux-stable-rc-4.19/747/config

-- 
Linaro LKFT
https://lkft.linaro.org