Hi,
On Wed, 13 Jan 2021 at 03:21, Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote:
>
> Hi,
>
<trim>
>
> This patch landed in linux next-20210112 as commit eaa7995c529b
> ("regulator: core: avoid regulator_resolve_supply() race condition"). I
> found that it triggers a following lockdep warning during the DWC3
> driver registration on some Exynos based boards (this log is from
> Samsung Exynos5420-based Peach-Pit board):
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 5.11.0-rc1-00008-geaa7995c529b #10095 Not tainted
> ------------------------------------------------------
> swapper/0/1 is trying to acquire lock:
> c12e1b80 (regulator_list_mutex){+.+.}-{3:3}, at:
> regulator_lock_dependent+0x4c/0x2b0
>
> but task is already holding lock:
> df7190c0 (regulator_ww_class_mutex){+.+.}-{3:3}, at:
> regulator_resolve_supply+0x44/0x318
LKFT testing also found this lockdep warning on
arm64 - hi6220-hikey while booting.
[ 0.635532] WARNING: possible recursive locking detected
[ 0.635558] 5.11.0-rc3-next-20210118 #1 Not tainted
[ 0.635585] --------------------------------------------
[ 0.635611] swapper/0/1 is trying to acquire lock:
[ 0.635636] ffff000000a13158
(regulator_ww_class_mutex){+.+.}-{3:3}, at:
regulator_lock_recursive+0x9c/0x1e8
[ 0.635721]
[ 0.635721] but task is already holding lock:
[ 0.635749] ffff000000a13958
(regulator_ww_class_mutex){+.+.}-{3:3}, at:
regulator_resolve_supply+0x70/0x2f0
[ 0.635817]
[ 0.635817] other info that might help us debug this:
[ 0.635847] Possible unsafe locking scenario:
[ 0.635847]
[ 0.635875] CPU0
[ 0.635892] ----
[ 0.635909] lock(regulator_ww_class_mutex);
[ 0.635942] lock(regulator_ww_class_mutex);
[ 0.635974]
[ 0.635974] *** DEADLOCK ***
[ 0.635974]
[ 0.636002] May be due to missing lock nesting notation
[ 0.636002]
[ 0.636033] 4 locks held by swapper/0/1:
[ 0.636057] #0: ffff000000a02988 (&dev->mutex){....}-{3:3}, at:
__device_driver_lock+0x38/0x70
[ 0.636131] #1: ffff000000a13958
(regulator_ww_class_mutex){+.+.}-{3:3}, at:
regulator_resolve_supply+0x70/0x2f0
[ 0.636205] #2: ffff800012b102c0
(regulator_list_mutex){+.+.}-{3:3}, at:
regulator_lock_dependent+0x5c/0x290
[ 0.636280] #3: ffff8000137e3918
(regulator_ww_class_acquire){+.+.}-{0:0}, at:
regulator_enable+0x40/0xe0
[ 0.636352]
[ 0.636352] stack backtrace:
[ 0.636378] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
5.11.0-rc3-next-20210118 #1
[ 0.636415] Hardware name: HiKey Development Board (DT)
[ 0.636443] Call trace:
[ 0.636460] dump_backtrace+0x0/0x1f0
[ 0.636490] show_stack+0x2c/0x80
[ 0.636516] dump_stack+0xf8/0x160
[ 0.636543] __lock_acquire+0xa3c/0x1718
[ 0.636571] lock_acquire+0x3d8/0x4f0
[ 0.636596] __ww_mutex_lock.constprop.14+0xbc/0xf68
[ 0.636628] ww_mutex_lock+0x6c/0x3e8
[ 0.636653] regulator_lock_recursive+0x9c/0x1e8
[ 0.636683] regulator_lock_dependent+0x198/0x290
[ 0.636713] regulator_enable+0x40/0xe0
[ 0.636739] regulator_resolve_supply+0x1e8/0x2f0
[ 0.636767] regulator_register_resolve_supply+0x24/0x80
[ 0.636797] class_for_each_device+0x78/0xf8
[ 0.636825] regulator_register+0x840/0xbb0
[ 0.636851] devm_regulator_register+0x50/0xa8
[ 0.636879] reg_fixed_voltage_probe+0x224/0x410
[ 0.636908] platform_probe+0x6c/0xd8
[ 0.636932] really_probe+0x2b8/0x520
[ 0.636960] driver_probe_device+0xf4/0x168
[ 0.636988] device_driver_attach+0x74/0x98
[ 0.637014] __driver_attach+0xc4/0x178
[ 0.637039] bus_for_each_dev+0x84/0xd8
[ 0.637066] driver_attach+0x30/0x40
[ 0.637092] bus_add_driver+0x170/0x258
[ 0.637119] driver_register+0x64/0x118
[ 0.637144] __platform_driver_register+0x34/0x40
[ 0.637172] regulator_fixed_voltage_init+0x20/0x28
[ 0.637205] do_one_initcall+0x94/0x4a0
[ 0.637231] kernel_init_freeable+0x2f0/0x344
[ 0.637261] kernel_init+0x18/0x120
Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Full boot log here:
https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20210118/testrun/3771538/suite/linux-log-parser/test/check-kernel-warning-2159912/log
metadata:
git branch: master
git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
git describe: next-20210112
kernel-config:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/hikey/lkft/linux-next/935/config
--
Linaro LKFT
https://lkft.linaro.org
