Re: [Freedreno] [PATCH] drm/msm/a6xx: Fix GMU lockdep splat
Hi,
On Thu, Aug 3, 2023 at 10:34 AM Rob Clark wrote:
>
> From: Rob Clark
>
> For normal GPU devfreq, we need to acquire the GMU lock while already
> holding devfreq locks. But in the teardown path, we were calling
> dev_pm_domain_detach() while already holding the GMU lock, resulting in
> this lockdep splat:
>
>==
>WARNING: possible circular locking dependency detected
>6.4.3-debug+ #3 Not tainted
>--
>ring0/391 is trying to acquire lock:
>ff80a025c078 (>lock){+.+.}-{3:3}, at:
> qos_notifier_call+0x30/0x74
>
>but task is already holding lock:
>ff809b8c1ce8 (&(c->notifiers)->rwsem){}-{3:3}, at:
> blocking_notifier_call_chain+0x34/0x78
>
>which lock already depends on the new lock.
>
>the existing dependency chain (in reverse order) is:
>
>-> #4 (&(c->notifiers)->rwsem){}-{3:3}:
> down_write+0x58/0x74
> __blocking_notifier_chain_register+0x64/0x84
> blocking_notifier_chain_register+0x1c/0x28
> freq_qos_add_notifier+0x5c/0x7c
> dev_pm_qos_add_notifier+0xd4/0xf0
> devfreq_add_device+0x42c/0x560
> devm_devfreq_add_device+0x6c/0xb8
> msm_devfreq_init+0xa8/0x16c [msm]
> msm_gpu_init+0x368/0x54c [msm]
> adreno_gpu_init+0x248/0x2b0 [msm]
> a6xx_gpu_init+0x2d0/0x384 [msm]
> adreno_bind+0x264/0x2bc [msm]
> component_bind_all+0x124/0x1f4
> msm_drm_bind+0x2d0/0x5f4 [msm]
> try_to_bring_up_aggregate_device+0x88/0x1a4
> __component_add+0xd4/0x128
> component_add+0x1c/0x28
> dp_display_probe+0x37c/0x3c0 [msm]
> platform_probe+0x70/0xc0
> really_probe+0x148/0x280
> __driver_probe_device+0xfc/0x114
> driver_probe_device+0x44/0x100
> __device_attach_driver+0x64/0xdc
> bus_for_each_drv+0xb0/0xd8
> __device_attach+0xe4/0x140
> device_initial_probe+0x1c/0x28
> bus_probe_device+0x44/0xb0
> deferred_probe_work_func+0xb0/0xc8
> process_one_work+0x288/0x3d8
> worker_thread+0x1f0/0x260
> kthread+0xf0/0x100
> ret_from_fork+0x10/0x20
>
>-> #3 (dev_pm_qos_mtx){+.+.}-{3:3}:
> __mutex_lock+0xc8/0x388
> mutex_lock_nested+0x2c/0x38
> dev_pm_qos_remove_notifier+0x3c/0xc8
> genpd_remove_device+0x40/0x11c
> genpd_dev_pm_detach+0x88/0x130
> dev_pm_domain_detach+0x2c/0x3c
> a6xx_gmu_remove+0x44/0xdc [msm]
> a6xx_destroy+0x7c/0xa4 [msm]
> adreno_unbind+0x50/0x64 [msm]
> component_unbind+0x44/0x64
> component_unbind_all+0xb4/0xbc
> msm_drm_uninit.isra.0+0x124/0x17c [msm]
> msm_drm_bind+0x340/0x5f4 [msm]
> try_to_bring_up_aggregate_device+0x88/0x1a4
> __component_add+0xd4/0x128
> component_add+0x1c/0x28
> dp_display_probe+0x37c/0x3c0 [msm]
> platform_probe+0x70/0xc0
> really_probe+0x148/0x280
> __driver_probe_device+0xfc/0x114
> driver_probe_device+0x44/0x100
> __device_attach_driver+0x64/0xdc
> bus_for_each_drv+0xb0/0xd8
> __device_attach+0xe4/0x140
> device_initial_probe+0x1c/0x28
> bus_probe_device+0x44/0xb0
> deferred_probe_work_func+0xb0/0xc8
> process_one_work+0x288/0x3d8
> worker_thread+0x1f0/0x260
> kthread+0xf0/0x100
> ret_from_fork+0x10/0x20
>
>-> #2 (_gpu->gmu.lock){+.+.}-{3:3}:
> __mutex_lock+0xc8/0x388
> mutex_lock_nested+0x2c/0x38
> a6xx_gpu_set_freq+0x38/0x64 [msm]
> msm_devfreq_target+0x170/0x18c [msm]
> devfreq_set_target+0x90/0x1e4
> devfreq_update_target+0xb4/0xf0
> update_devfreq+0x1c/0x28
> devfreq_monitor+0x3c/0x10c
> process_one_work+0x288/0x3d8
> worker_thread+0x1f0/0x260
> kthread+0xf0/0x100
> ret_from_fork+0x10/0x20
>
>-> #1 (>lock){+.+.}-{3:3}:
> __mutex_lock+0xc8/0x388
> mutex_lock_nested+0x2c/0x38
> msm_devfreq_get_dev_status+0x4c/0x104 [msm]
> devfreq_simple_ondemand_func+0x5c/0x128
> devfreq_update_target+0x68/0xf0
> update_devfreq+0x1c/0x28
> devfreq_monitor+0x3c/0x10c
> process_one_work+0x288/0x3d8
> worker_thread+0x1f0/0x260
> kthread+0xf0/0x100
> ret_from_fork+0x10/0x20
>
>-> #0 (>lock){+.+.}-{3:3}:
> __lock_acquire+0xdf8/0x109c
> lock_acquire+0x234/0x284
> __mutex_lock+0xc8/0x388
> mutex_lock_nested+0x2c/0x38
> qos_notifier_call+0x30/0x74
> qos_min_notifier_call+0x1c/0x28
> notifier_call_chain+0xf4/0x114
>
[Freedreno] [PATCH] drm/msm/a6xx: Fix GMU lockdep splat
From: Rob Clark
For normal GPU devfreq, we need to acquire the GMU lock while already
holding devfreq locks. But in the teardown path, we were calling
dev_pm_domain_detach() while already holding the GMU lock, resulting in
this lockdep splat:
==
WARNING: possible circular locking dependency detected
6.4.3-debug+ #3 Not tainted
--
ring0/391 is trying to acquire lock:
ff80a025c078 (>lock){+.+.}-{3:3}, at:
qos_notifier_call+0x30/0x74
but task is already holding lock:
ff809b8c1ce8 (&(c->notifiers)->rwsem){}-{3:3}, at:
blocking_notifier_call_chain+0x34/0x78
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&(c->notifiers)->rwsem){}-{3:3}:
down_write+0x58/0x74
__blocking_notifier_chain_register+0x64/0x84
blocking_notifier_chain_register+0x1c/0x28
freq_qos_add_notifier+0x5c/0x7c
dev_pm_qos_add_notifier+0xd4/0xf0
devfreq_add_device+0x42c/0x560
devm_devfreq_add_device+0x6c/0xb8
msm_devfreq_init+0xa8/0x16c [msm]
msm_gpu_init+0x368/0x54c [msm]
adreno_gpu_init+0x248/0x2b0 [msm]
a6xx_gpu_init+0x2d0/0x384 [msm]
adreno_bind+0x264/0x2bc [msm]
component_bind_all+0x124/0x1f4
msm_drm_bind+0x2d0/0x5f4 [msm]
try_to_bring_up_aggregate_device+0x88/0x1a4
__component_add+0xd4/0x128
component_add+0x1c/0x28
dp_display_probe+0x37c/0x3c0 [msm]
platform_probe+0x70/0xc0
really_probe+0x148/0x280
__driver_probe_device+0xfc/0x114
driver_probe_device+0x44/0x100
__device_attach_driver+0x64/0xdc
bus_for_each_drv+0xb0/0xd8
__device_attach+0xe4/0x140
device_initial_probe+0x1c/0x28
bus_probe_device+0x44/0xb0
deferred_probe_work_func+0xb0/0xc8
process_one_work+0x288/0x3d8
worker_thread+0x1f0/0x260
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
-> #3 (dev_pm_qos_mtx){+.+.}-{3:3}:
__mutex_lock+0xc8/0x388
mutex_lock_nested+0x2c/0x38
dev_pm_qos_remove_notifier+0x3c/0xc8
genpd_remove_device+0x40/0x11c
genpd_dev_pm_detach+0x88/0x130
dev_pm_domain_detach+0x2c/0x3c
a6xx_gmu_remove+0x44/0xdc [msm]
a6xx_destroy+0x7c/0xa4 [msm]
adreno_unbind+0x50/0x64 [msm]
component_unbind+0x44/0x64
component_unbind_all+0xb4/0xbc
msm_drm_uninit.isra.0+0x124/0x17c [msm]
msm_drm_bind+0x340/0x5f4 [msm]
try_to_bring_up_aggregate_device+0x88/0x1a4
__component_add+0xd4/0x128
component_add+0x1c/0x28
dp_display_probe+0x37c/0x3c0 [msm]
platform_probe+0x70/0xc0
really_probe+0x148/0x280
__driver_probe_device+0xfc/0x114
driver_probe_device+0x44/0x100
__device_attach_driver+0x64/0xdc
bus_for_each_drv+0xb0/0xd8
__device_attach+0xe4/0x140
device_initial_probe+0x1c/0x28
bus_probe_device+0x44/0xb0
deferred_probe_work_func+0xb0/0xc8
process_one_work+0x288/0x3d8
worker_thread+0x1f0/0x260
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
-> #2 (_gpu->gmu.lock){+.+.}-{3:3}:
__mutex_lock+0xc8/0x388
mutex_lock_nested+0x2c/0x38
a6xx_gpu_set_freq+0x38/0x64 [msm]
msm_devfreq_target+0x170/0x18c [msm]
devfreq_set_target+0x90/0x1e4
devfreq_update_target+0xb4/0xf0
update_devfreq+0x1c/0x28
devfreq_monitor+0x3c/0x10c
process_one_work+0x288/0x3d8
worker_thread+0x1f0/0x260
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
-> #1 (>lock){+.+.}-{3:3}:
__mutex_lock+0xc8/0x388
mutex_lock_nested+0x2c/0x38
msm_devfreq_get_dev_status+0x4c/0x104 [msm]
devfreq_simple_ondemand_func+0x5c/0x128
devfreq_update_target+0x68/0xf0
update_devfreq+0x1c/0x28
devfreq_monitor+0x3c/0x10c
process_one_work+0x288/0x3d8
worker_thread+0x1f0/0x260
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
-> #0 (>lock){+.+.}-{3:3}:
__lock_acquire+0xdf8/0x109c
lock_acquire+0x234/0x284
__mutex_lock+0xc8/0x388
mutex_lock_nested+0x2c/0x38
qos_notifier_call+0x30/0x74
qos_min_notifier_call+0x1c/0x28
notifier_call_chain+0xf4/0x114
blocking_notifier_call_chain+0x4c/0x78
pm_qos_update_target+0x184/0x190
freq_qos_apply+0x4c/0x64
apply_constraint+0xf8/0xfc
__dev_pm_qos_update_request+0x138/0x164
dev_pm_qos_update_request+0x44/0x68
msm_devfreq_boost+0x40/0x70 [msm]
