| Message ID | 20230803173431.48947-1-robdclark@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/msm/a6xx: Fix GMU lockdep splat | expand |
Hi, On Thu, Aug 3, 2023 at 10:34 AM Rob Clark <robdclark@gmail.com> wrote: > > From: Rob Clark <robdclark@chromium.org> > > 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: > ffffff80a025c078 (&devfreq->lock){+.+.}-{3:3}, at: qos_notifier_call+0x30/0x74 > > but task is already holding lock: > ffffff809b8c1ce8 (&(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 (&a6xx_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 (&df->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 (&devfreq->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] > msm_devfreq_active+0xc0/0xf0 [msm] > msm_gpu_submit+0xc8/0x12c [msm] > msm_job_run+0x88/0x128 [msm] > drm_sched_main+0x240/0x324 [gpu_sched] > kthread+0xf0/0x100 > ret_from_fork+0x10/0x20 > > other info that might help us debug this: > Chain exists of: > &devfreq->lock --> dev_pm_qos_mtx --> &(c->notifiers)->rwsem > Possible unsafe locking scenario: > CPU0 CPU1 > ---- ---- > rlock(&(c->notifiers)->rwsem); > lock(dev_pm_qos_mtx); > lock(&(c->notifiers)->rwsem); > lock(&devfreq->lock); > > *** DEADLOCK *** > 4 locks held by ring0/391: > #0: ffffff809c811170 (&gpu->lock){+.+.}-{3:3}, at: msm_job_run+0x7c/0x128 [msm] > #1: ffffff809c811208 (&gpu->active_lock){+.+.}-{3:3}, at: msm_gpu_submit+0xa8/0x12c [msm] > #2: ffffffecbbb46600 (dev_pm_qos_mtx){+.+.}-{3:3}, at: dev_pm_qos_update_request+0x38/0x68 > #3: ffffff809b8c1ce8 (&(c->notifiers)->rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x34/0x78 > > stack backtrace: > CPU: 6 PID: 391 Comm: ring0 Not tainted 6.4.3debug+ #3 > Hardware name: Google Villager (rev1+) with LTE (DT) > Call trace: > dump_backtrace+0xb4/0xf0 > show_stack+0x20/0x30 > dump_stack_lvl+0x60/0x84 > dump_stack+0x18/0x24 > print_circular_bug+0x1cc/0x234 > check_noncircular+0x78/0xac > __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] > msm_devfreq_active+0xc0/0xf0 [msm] > msm_gpu_submit+0xc8/0x12c [msm] > msm_job_run+0x88/0x128 [msm] > drm_sched_main+0x240/0x324 [gpu_sched] > kthread+0xf0/0x100 > ret_from_fork+0x10/0x20 > > Fix this by only synchronizing access to gmu->initialized. > > Fixes: 4cd15a3e8b36 ("drm/msm/a6xx: Make GPU destroy a bit safer") > Cc: Douglas Anderson <dianders@chromium.org> > Signed-off-by: Rob Clark <robdclark@chromium.org> > --- > drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 11 ++++++++--- > drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 2 -- > 2 files changed, 8 insertions(+), 5 deletions(-) While this is tangled enough that I can't necessarily think through every aspect of it, this seems to me like it should do the trick. Thanks for the fix! Reviewed-by: Douglas Anderson <dianders@chromium.org> -Doug
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c index bf7f855f4a34..3e0033666a2a 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c @@ -1441,8 +1441,15 @@ void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu) struct a6xx_gmu *gmu = &a6xx_gpu->gmu; struct platform_device *pdev = to_platform_device(gmu->dev); - if (!gmu->initialized) + mutex_lock(&gmu->lock); + if (!gmu->initialized) { + mutex_unlock(&gmu->lock); return; + } + + gmu->initialized = false; + + mutex_unlock(&gmu->lock); pm_runtime_force_suspend(gmu->dev); @@ -1472,8 +1479,6 @@ void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu) /* Drop reference taken in of_find_device_by_node */ put_device(gmu->dev); - - gmu->initialized = false; } static int cxpd_notifier_cb(struct notifier_block *nb, diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c index 9be3260c8033..67dd2eeecf62 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c @@ -2091,9 +2091,7 @@ static void a6xx_destroy(struct msm_gpu *gpu) a6xx_llc_slices_destroy(a6xx_gpu); - mutex_lock(&a6xx_gpu->gmu.lock); a6xx_gmu_remove(a6xx_gpu); - mutex_unlock(&a6xx_gpu->gmu.lock); adreno_gpu_cleanup(adreno_gpu);