* [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe
@ 2023-03-20 14:43 Rob Clark
2023-03-20 14:43 ` [PATCH v2 15/23] PM / devfreq: Drop unneed locking to appease lockdep Rob Clark
` (7 more replies)
0 siblings, 8 replies; 14+ messages in thread
From: Rob Clark @ 2023-03-20 14:43 UTC (permalink / raw)
To: dri-devel
Cc: Daniel Vetter, freedreno, linux-arm-msm, Rob Clark,
Akhil P Oommen, Chia-I Wu, Dmitry Baryshkov, Douglas Anderson,
Geert Uytterhoeven, Joel Fernandes (Google),
Konrad Dybcio, Konrad Dybcio,
moderated list:DMA BUFFER SHARING FRAMEWORK, open list,
open list:DMA BUFFER SHARING FRAMEWORK,
open list:DEVICE FREQUENCY (DEVFREQ),
Luca Weiss, Maximilian Luz, Nathan Chancellor, Rafael J. Wysocki,
Sean Paul
From: Rob Clark <robdclark@chromium.org>
Inspired by https://lore.kernel.org/dri-devel/20200604081224.863494-10-daniel.vetter@ffwll.ch/
it seemed like a good idea to get rid of memory allocation in job_run()
fence signaling path, and use lockdep annotations to yell at us about
anything that could deadlock against shrinker/reclaim. Anything that
can trigger reclaim, or block on any other thread that has triggered
reclaim, can block the GPU shrinker from releasing memory if it is
waiting the job to complete, causing deadlock.
The first patch pre-allocates the hw_fence, splitting allocation and
initialization, to avoid allocation in the job_run() path. The next
eight decouple the obj lock from job_run(), as the obj lock is required
to pin/unpin backing pages (ie. holding an obj lock in job_run() could
deadlock the shrinker by blocking forward progress towards pinned buffers
becoming idle). Followed by two so that we could idr_preload() in order
to avoid memory allocations under locks indirectly connected to the
shrinker path.
Next are three paths to decouple initialization (where allocations are
needed) from GPU runpm and devfreq, to avoid allocations in the fence
signaling path. Followed by various PM devfreq/qos and interconnect
locking fixes to decouple initialization (allocation) from runtime.
And finally, the last patch is a modified version of danvet's patch to
add lockdep annotations to gpu scheduler, but does so conditionally so
that drivers can opt-in.
v2: Switch from embedding hw_fence in submit/job object to preallocating
the hw_fence. Rework "fenced unpin" locking to drop obj lock from
fence signaling path (ie. the part that was still WIP in the first
iteration of the patchset). Adds the final patch to enable fence
signaling annotations now that job_run() and job_free() are safe.
The PM devfreq/QoS and interconnect patches are unchanged.
Rob Clark (23):
drm/msm: Pre-allocate hw_fence
drm/msm: Move submit bo flags update from obj lock
drm/msm/gem: Tidy up VMA API
drm/msm: Decouple vma tracking from obj lock
drm/msm/gem: Simplify vmap vs LRU tracking
drm/gem: Export drm_gem_lru_move_tail_locked()
drm/msm/gem: Move update_lru()
drm/msm/gem: Protect pin_count/madv by LRU lock
drm/msm/gem: Avoid obj lock in job_run()
drm/msm: Switch idr_lock to spinlock
drm/msm: Use idr_preload()
drm/msm/gpu: Move fw loading out of hw_init() path
drm/msm/gpu: Move BO allocation out of hw_init
drm/msm/a6xx: Move ioremap out of hw_init path
PM / devfreq: Drop unneed locking to appease lockdep
PM / devfreq: Teach lockdep about locking order
PM / QoS: Fix constraints alloc vs reclaim locking
PM / QoS: Decouple request alloc from dev_pm_qos_mtx
PM / QoS: Teach lockdep about dev_pm_qos_mtx locking order
soc: qcom: smd-rpm: Use GFP_ATOMIC in write path
interconnect: Fix locking for runpm vs reclaim
interconnect: Teach lockdep about icc_bw_lock order
drm/sched: Add (optional) fence signaling annotation
drivers/base/power/qos.c | 83 +++++++++---
drivers/devfreq/devfreq.c | 52 ++++----
drivers/gpu/drm/drm_gem.c | 11 +-
drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 48 ++++---
drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 18 ++-
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 46 ++++---
drivers/gpu/drm/msm/adreno/adreno_device.c | 6 +
drivers/gpu/drm/msm/adreno/adreno_gpu.c | 9 +-
drivers/gpu/drm/msm/msm_drv.c | 6 +-
drivers/gpu/drm/msm/msm_fence.c | 12 +-
drivers/gpu/drm/msm/msm_fence.h | 3 +-
drivers/gpu/drm/msm/msm_gem.c | 145 ++++++++++++++-------
drivers/gpu/drm/msm/msm_gem.h | 29 +++--
drivers/gpu/drm/msm/msm_gem_submit.c | 27 ++--
drivers/gpu/drm/msm/msm_gem_vma.c | 91 ++++++++++---
drivers/gpu/drm/msm/msm_gpu.h | 8 +-
drivers/gpu/drm/msm/msm_ringbuffer.c | 9 +-
drivers/gpu/drm/msm/msm_submitqueue.c | 2 +-
drivers/gpu/drm/scheduler/sched_main.c | 9 ++
drivers/interconnect/core.c | 18 ++-
drivers/soc/qcom/smd-rpm.c | 2 +-
include/drm/drm_gem.h | 1 +
include/drm/gpu_scheduler.h | 2 +
23 files changed, 416 insertions(+), 221 deletions(-)
--
2.39.2
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH v2 15/23] PM / devfreq: Drop unneed locking to appease lockdep
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
@ 2023-03-20 14:43 ` Rob Clark
2023-03-20 14:43 ` [PATCH v2 16/23] PM / devfreq: Teach lockdep about locking order Rob Clark
` (6 subsequent siblings)
7 siblings, 0 replies; 14+ messages in thread
From: Rob Clark @ 2023-03-20 14:43 UTC (permalink / raw)
To: dri-devel
Cc: Daniel Vetter, freedreno, linux-arm-msm, Rob Clark, MyungJoo Ham,
Kyungmin Park, Chanwoo Choi, open list:DEVICE FREQUENCY (DEVFREQ),
open list
From: Rob Clark <robdclark@chromium.org>
In the process of adding lockdep annotation for GPU job_run() path to
catch potential deadlocks against the shrinker/reclaim path, I turned
up this lockdep splat:
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc8-debug+ #556 Not tainted
------------------------------------------------------
ring0/123 is trying to acquire lock:
ffffff8087219078 (&devfreq->lock){+.+.}-{3:3}, at: devfreq_monitor_resume+0x3c/0xf0
but task is already holding lock:
ffffffd6f64e57e8 (dma_fence_map){++++}-{0:0}, at: msm_job_run+0x68/0x150
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (dma_fence_map){++++}-{0:0}:
__dma_fence_might_wait+0x74/0xc0
dma_resv_lockdep+0x1f4/0x2f4
do_one_initcall+0x104/0x2bc
kernel_init_freeable+0x344/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #2 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}:
fs_reclaim_acquire+0x80/0xa8
slab_pre_alloc_hook.constprop.0+0x40/0x25c
__kmem_cache_alloc_node+0x60/0x1cc
__kmalloc+0xd8/0x100
topology_parse_cpu_capacity+0x8c/0x178
get_cpu_for_node+0x88/0xc4
parse_cluster+0x1b0/0x28c
parse_cluster+0x8c/0x28c
init_cpu_topology+0x168/0x188
smp_prepare_cpus+0x24/0xf8
kernel_init_freeable+0x18c/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire+0x3c/0x48
fs_reclaim_acquire+0x54/0xa8
slab_pre_alloc_hook.constprop.0+0x40/0x25c
__kmem_cache_alloc_node+0x60/0x1cc
__kmalloc_node_track_caller+0xb8/0xe0
kstrdup+0x70/0x90
kstrdup_const+0x38/0x48
kvasprintf_const+0x48/0xbc
kobject_set_name_vargs+0x40/0xb0
dev_set_name+0x64/0x8c
devfreq_add_device+0x31c/0x55c
devm_devfreq_add_device+0x6c/0xb8
msm_devfreq_init+0xa8/0x16c
msm_gpu_init+0x38c/0x570
adreno_gpu_init+0x1b4/0x2b4
a6xx_gpu_init+0x15c/0x3e4
adreno_bind+0x218/0x254
component_bind_all+0x114/0x1ec
msm_drm_bind+0x2b8/0x608
try_to_bring_up_aggregate_device+0x88/0x1a4
__component_add+0xec/0x13c
component_add+0x1c/0x28
dsi_dev_attach+0x28/0x34
dsi_host_attach+0xdc/0x124
mipi_dsi_attach+0x30/0x44
devm_mipi_dsi_attach+0x2c/0x70
ti_sn_bridge_probe+0x298/0x2c4
auxiliary_bus_probe+0x7c/0x94
really_probe+0x158/0x290
__driver_probe_device+0xc8/0xe0
driver_probe_device+0x44/0x100
__device_attach_driver+0x64/0xdc
bus_for_each_drv+0xa0/0xc8
__device_attach+0xd8/0x168
device_initial_probe+0x1c/0x28
bus_probe_device+0x38/0xa0
deferred_probe_work_func+0xc8/0xe0
process_one_work+0x2d8/0x478
process_scheduled_works+0x4c/0x50
worker_thread+0x218/0x274
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
-> #0 (&devfreq->lock){+.+.}-{3:3}:
__lock_acquire+0xe00/0x1060
lock_acquire+0x1e0/0x2f8
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
devfreq_monitor_resume+0x3c/0xf0
devfreq_simple_ondemand_handler+0x54/0x7c
devfreq_resume_device+0xa4/0xe8
msm_devfreq_resume+0x78/0xa8
a6xx_pm_resume+0x110/0x234
adreno_runtime_resume+0x2c/0x38
pm_generic_runtime_resume+0x30/0x44
__rpm_callback+0x15c/0x174
rpm_callback+0x78/0x7c
rpm_resume+0x318/0x524
__pm_runtime_resume+0x78/0xbc
pm_runtime_get_sync.isra.0+0x14/0x20
msm_gpu_submit+0x58/0x178
msm_job_run+0x78/0x150
drm_sched_main+0x290/0x370
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
other info that might help us debug this:
Chain exists of:
&devfreq->lock --> mmu_notifier_invalidate_range_start --> dma_fence_map
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(dma_fence_map);
lock(mmu_notifier_invalidate_range_start);
lock(dma_fence_map);
lock(&devfreq->lock);
*** DEADLOCK ***
2 locks held by ring0/123:
#0: ffffff8087201170 (&gpu->lock){+.+.}-{3:3}, at: msm_job_run+0x64/0x150
#1: ffffffd6f64e57e8 (dma_fence_map){++++}-{0:0}, at: msm_job_run+0x68/0x150
stack backtrace:
CPU: 6 PID: 123 Comm: ring0 Not tainted 6.2.0-rc8-debug+ #556
Hardware name: Google Lazor (rev1 - 2) with LTE (DT)
Call trace:
dump_backtrace.part.0+0xb4/0xf8
show_stack+0x20/0x38
dump_stack_lvl+0x9c/0xd0
dump_stack+0x18/0x34
print_circular_bug+0x1b4/0x1f0
check_noncircular+0x78/0xac
__lock_acquire+0xe00/0x1060
lock_acquire+0x1e0/0x2f8
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
devfreq_monitor_resume+0x3c/0xf0
devfreq_simple_ondemand_handler+0x54/0x7c
devfreq_resume_device+0xa4/0xe8
msm_devfreq_resume+0x78/0xa8
a6xx_pm_resume+0x110/0x234
adreno_runtime_resume+0x2c/0x38
pm_generic_runtime_resume+0x30/0x44
__rpm_callback+0x15c/0x174
rpm_callback+0x78/0x7c
rpm_resume+0x318/0x524
__pm_runtime_resume+0x78/0xbc
pm_runtime_get_sync.isra.0+0x14/0x20
msm_gpu_submit+0x58/0x178
msm_job_run+0x78/0x150
drm_sched_main+0x290/0x370
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
The issue is that we cannot be holding any lock while doing memory
allocations that is also needed in the job_run (and in the case of
devfreq, this means runpm_resume()) because lockdep sees this as a
potential dependency.
Fortunately there is really no reason to hold the devfreq lock when
we are creating the devfreq device, as it is not yet visible to any
other task. The only reason it was needed was for a lockdep assert
in devfreq_get_freq_range(). Instead, split this up into an internal
fxn that is used in the devfreq_add_device() (where the lock is not
required).
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/devfreq/devfreq.c | 46 ++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 25 deletions(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 817c71da391a..11b774048bd2 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -111,23 +111,13 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
return max_freq;
}
-/**
- * devfreq_get_freq_range() - Get the current freq range
- * @devfreq: the devfreq instance
- * @min_freq: the min frequency
- * @max_freq: the max frequency
- *
- * This takes into consideration all constraints.
- */
-void devfreq_get_freq_range(struct devfreq *devfreq,
- unsigned long *min_freq,
- unsigned long *max_freq)
+static void __get_freq_range(struct devfreq *devfreq,
+ unsigned long *min_freq,
+ unsigned long *max_freq)
{
unsigned long *freq_table = devfreq->freq_table;
s32 qos_min_freq, qos_max_freq;
- lockdep_assert_held(&devfreq->lock);
-
/*
* Initialize minimum/maximum frequency from freq table.
* The devfreq drivers can initialize this in either ascending or
@@ -158,6 +148,23 @@ void devfreq_get_freq_range(struct devfreq *devfreq,
if (*min_freq > *max_freq)
*min_freq = *max_freq;
}
+
+/**
+ * devfreq_get_freq_range() - Get the current freq range
+ * @devfreq: the devfreq instance
+ * @min_freq: the min frequency
+ * @max_freq: the max frequency
+ *
+ * This takes into consideration all constraints.
+ */
+void devfreq_get_freq_range(struct devfreq *devfreq,
+ unsigned long *min_freq,
+ unsigned long *max_freq)
+{
+ lockdep_assert_held(&devfreq->lock);
+
+ __get_freq_range(devfreq, min_freq, max_freq);
+}
EXPORT_SYMBOL(devfreq_get_freq_range);
/**
@@ -810,7 +817,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
}
mutex_init(&devfreq->lock);
- mutex_lock(&devfreq->lock);
devfreq->dev.parent = dev;
devfreq->dev.class = devfreq_class;
devfreq->dev.release = devfreq_dev_release;
@@ -823,17 +829,14 @@ struct devfreq *devfreq_add_device(struct device *dev,
if (devfreq->profile->timer < 0
|| devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
- mutex_unlock(&devfreq->lock);
err = -EINVAL;
goto err_dev;
}
if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
- mutex_unlock(&devfreq->lock);
err = set_freq_table(devfreq);
if (err < 0)
goto err_dev;
- mutex_lock(&devfreq->lock);
} else {
devfreq->freq_table = devfreq->profile->freq_table;
devfreq->max_state = devfreq->profile->max_state;
@@ -841,19 +844,17 @@ struct devfreq *devfreq_add_device(struct device *dev,
devfreq->scaling_min_freq = find_available_min_freq(devfreq);
if (!devfreq->scaling_min_freq) {
- mutex_unlock(&devfreq->lock);
err = -EINVAL;
goto err_dev;
}
devfreq->scaling_max_freq = find_available_max_freq(devfreq);
if (!devfreq->scaling_max_freq) {
- mutex_unlock(&devfreq->lock);
err = -EINVAL;
goto err_dev;
}
- devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
+ __get_freq_range(devfreq, &min_freq, &max_freq);
devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
@@ -865,7 +866,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
dev_set_name(&devfreq->dev, "%s", dev_name(dev));
err = device_register(&devfreq->dev);
if (err) {
- mutex_unlock(&devfreq->lock);
put_device(&devfreq->dev);
goto err_out;
}
@@ -876,7 +876,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
devfreq->max_state),
GFP_KERNEL);
if (!devfreq->stats.trans_table) {
- mutex_unlock(&devfreq->lock);
err = -ENOMEM;
goto err_devfreq;
}
@@ -886,7 +885,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
sizeof(*devfreq->stats.time_in_state),
GFP_KERNEL);
if (!devfreq->stats.time_in_state) {
- mutex_unlock(&devfreq->lock);
err = -ENOMEM;
goto err_devfreq;
}
@@ -896,8 +894,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
srcu_init_notifier_head(&devfreq->transition_notifier_list);
- mutex_unlock(&devfreq->lock);
-
err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
DEV_PM_QOS_MIN_FREQUENCY, 0);
if (err < 0)
--
2.39.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v2 16/23] PM / devfreq: Teach lockdep about locking order
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
2023-03-20 14:43 ` [PATCH v2 15/23] PM / devfreq: Drop unneed locking to appease lockdep Rob Clark
@ 2023-03-20 14:43 ` Rob Clark
2023-03-20 14:43 ` [PATCH v2 17/23] PM / QoS: Fix constraints alloc vs reclaim locking Rob Clark
` (5 subsequent siblings)
7 siblings, 0 replies; 14+ messages in thread
From: Rob Clark @ 2023-03-20 14:43 UTC (permalink / raw)
To: dri-devel
Cc: Daniel Vetter, freedreno, linux-arm-msm, Rob Clark, MyungJoo Ham,
Kyungmin Park, Chanwoo Choi, open list:DEVICE FREQUENCY (DEVFREQ),
open list
From: Rob Clark <robdclark@chromium.org>
This will make it easier to catch places doing allocations that can
trigger reclaim under devfreq->lock.
Because devfreq->lock is held over various devfreq_dev_profile
callbacks, there might be some fallout if those callbacks do allocations
that can trigger reclaim, but I've looked through the various callback
implementations and don't see anything obvious. If it does trigger any
lockdep splats, those should be fixed.
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/devfreq/devfreq.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 11b774048bd2..5ce3bf9b59e7 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -817,6 +817,12 @@ struct devfreq *devfreq_add_device(struct device *dev,
}
mutex_init(&devfreq->lock);
+
+ /* Teach lockdep about lock ordering wrt. shrinker: */
+ fs_reclaim_acquire(GFP_KERNEL);
+ might_lock(&devfreq->lock);
+ fs_reclaim_release(GFP_KERNEL);
+
devfreq->dev.parent = dev;
devfreq->dev.class = devfreq_class;
devfreq->dev.release = devfreq_dev_release;
--
2.39.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v2 17/23] PM / QoS: Fix constraints alloc vs reclaim locking
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
2023-03-20 14:43 ` [PATCH v2 15/23] PM / devfreq: Drop unneed locking to appease lockdep Rob Clark
2023-03-20 14:43 ` [PATCH v2 16/23] PM / devfreq: Teach lockdep about locking order Rob Clark
@ 2023-03-20 14:43 ` Rob Clark
2023-03-27 17:53 ` Rafael J. Wysocki
2023-03-20 14:43 ` [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx Rob Clark
` (4 subsequent siblings)
7 siblings, 1 reply; 14+ messages in thread
From: Rob Clark @ 2023-03-20 14:43 UTC (permalink / raw)
To: dri-devel
Cc: Daniel Vetter, freedreno, linux-arm-msm, Rob Clark,
Rafael J. Wysocki, Pavel Machek, Len Brown, Greg Kroah-Hartman,
open list:HIBERNATION (aka Software Suspend, aka swsusp),
open list
From: Rob Clark <robdclark@chromium.org>
In the process of adding lockdep annotation for drm GPU scheduler's
job_run() to detect potential deadlock against shrinker/reclaim, I hit
this lockdep splat:
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc8-debug+ #558 Tainted: G W
------------------------------------------------------
ring0/125 is trying to acquire lock:
ffffffd6d6ce0f28 (dev_pm_qos_mtx){+.+.}-{3:3}, at: dev_pm_qos_update_request+0x38/0x68
but task is already holding lock:
ffffff8087239208 (&gpu->active_lock){+.+.}-{3:3}, at: msm_gpu_submit+0xec/0x178
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&gpu->active_lock){+.+.}-{3:3}:
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
msm_gpu_submit+0xec/0x178
msm_job_run+0x78/0x150
drm_sched_main+0x290/0x370
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
-> #3 (dma_fence_map){++++}-{0:0}:
__dma_fence_might_wait+0x74/0xc0
dma_resv_lockdep+0x1f4/0x2f4
do_one_initcall+0x104/0x2bc
kernel_init_freeable+0x344/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #2 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}:
fs_reclaim_acquire+0x80/0xa8
slab_pre_alloc_hook.constprop.0+0x40/0x25c
__kmem_cache_alloc_node+0x60/0x1cc
__kmalloc+0xd8/0x100
topology_parse_cpu_capacity+0x8c/0x178
get_cpu_for_node+0x88/0xc4
parse_cluster+0x1b0/0x28c
parse_cluster+0x8c/0x28c
init_cpu_topology+0x168/0x188
smp_prepare_cpus+0x24/0xf8
kernel_init_freeable+0x18c/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire+0x3c/0x48
fs_reclaim_acquire+0x54/0xa8
slab_pre_alloc_hook.constprop.0+0x40/0x25c
__kmem_cache_alloc_node+0x60/0x1cc
kmalloc_trace+0x50/0xa8
dev_pm_qos_constraints_allocate+0x38/0x100
__dev_pm_qos_add_request+0xb0/0x1e8
dev_pm_qos_add_request+0x58/0x80
dev_pm_qos_expose_latency_limit+0x60/0x13c
register_cpu+0x12c/0x130
topology_init+0xac/0xbc
do_one_initcall+0x104/0x2bc
kernel_init_freeable+0x344/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #0 (dev_pm_qos_mtx){+.+.}-{3:3}:
__lock_acquire+0xe00/0x1060
lock_acquire+0x1e0/0x2f8
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
dev_pm_qos_update_request+0x38/0x68
msm_devfreq_boost+0x40/0x70
msm_devfreq_active+0xc0/0xf0
msm_gpu_submit+0x10c/0x178
msm_job_run+0x78/0x150
drm_sched_main+0x290/0x370
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
other info that might help us debug this:
Chain exists of:
dev_pm_qos_mtx --> dma_fence_map --> &gpu->active_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&gpu->active_lock);
lock(dma_fence_map);
lock(&gpu->active_lock);
lock(dev_pm_qos_mtx);
*** DEADLOCK ***
3 locks held by ring0/123:
#0: ffffff8087251170 (&gpu->lock){+.+.}-{3:3}, at: msm_job_run+0x64/0x150
#1: ffffffd00b0e57e8 (dma_fence_map){++++}-{0:0}, at: msm_job_run+0x68/0x150
#2: ffffff8087251208 (&gpu->active_lock){+.+.}-{3:3}, at: msm_gpu_submit+0xec/0x178
stack backtrace:
CPU: 6 PID: 123 Comm: ring0 Not tainted 6.2.0-rc8-debug+ #559
Hardware name: Google Lazor (rev1 - 2) with LTE (DT)
Call trace:
dump_backtrace.part.0+0xb4/0xf8
show_stack+0x20/0x38
dump_stack_lvl+0x9c/0xd0
dump_stack+0x18/0x34
print_circular_bug+0x1b4/0x1f0
check_noncircular+0x78/0xac
__lock_acquire+0xe00/0x1060
lock_acquire+0x1e0/0x2f8
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
dev_pm_qos_update_request+0x38/0x68
msm_devfreq_boost+0x40/0x70
msm_devfreq_active+0xc0/0xf0
msm_gpu_submit+0x10c/0x178
msm_job_run+0x78/0x150
drm_sched_main+0x290/0x370
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
The issue is that dev_pm_qos_mtx is held in the runpm suspend/resume (or
freq change) path, but it is also held across allocations that could
recurse into shrinker.
Solve this by changing dev_pm_qos_constraints_allocate() into a function
that can be called unconditionally before the device qos object is
needed and before aquiring dev_pm_qos_mtx. This way the allocations can
be done without holding the mutex. In the case that we raced with
another thread to allocate the qos object, detect this *after* acquiring
the dev_pm_qos_mtx and simply free the redundant allocations.
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/base/power/qos.c | 60 +++++++++++++++++++++++++++-------------
1 file changed, 41 insertions(+), 19 deletions(-)
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 8e93167f1783..f3e0c6b65635 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -185,18 +185,24 @@ static int apply_constraint(struct dev_pm_qos_request *req,
}
/*
- * dev_pm_qos_constraints_allocate
+ * dev_pm_qos_constraints_ensure_allocated
* @dev: device to allocate data for
*
- * Called at the first call to add_request, for constraint data allocation
- * Must be called with the dev_pm_qos_mtx mutex held
+ * Called to ensure that devices qos is allocated, before acquiring
+ * dev_pm_qos_mtx.
*/
-static int dev_pm_qos_constraints_allocate(struct device *dev)
+static int dev_pm_qos_constraints_ensure_allocated(struct device *dev)
{
struct dev_pm_qos *qos;
struct pm_qos_constraints *c;
struct blocking_notifier_head *n;
+ if (!dev)
+ return -ENODEV;
+
+ if (!IS_ERR_OR_NULL(dev->power.qos))
+ return 0;
+
qos = kzalloc(sizeof(*qos), GFP_KERNEL);
if (!qos)
return -ENOMEM;
@@ -227,10 +233,26 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
INIT_LIST_HEAD(&qos->flags.list);
+ mutex_lock(&dev_pm_qos_mtx);
+
+ if (!IS_ERR_OR_NULL(dev->power.qos)) {
+ /*
+ * We have raced with another task to create the qos.
+ * No biggie, just free the resources we've allocated
+ * outside of dev_pm_qos_mtx and move on with life.
+ */
+ kfree(n);
+ kfree(qos);
+ goto unlock;
+ }
+
spin_lock_irq(&dev->power.lock);
dev->power.qos = qos;
spin_unlock_irq(&dev->power.lock);
+unlock:
+ mutex_unlock(&dev_pm_qos_mtx);
+
return 0;
}
@@ -331,17 +353,15 @@ static int __dev_pm_qos_add_request(struct device *dev,
{
int ret = 0;
- if (!dev || !req || dev_pm_qos_invalid_req_type(dev, type))
+ if (!req || dev_pm_qos_invalid_req_type(dev, type))
return -EINVAL;
if (WARN(dev_pm_qos_request_active(req),
"%s() called for already added request\n", __func__))
return -EINVAL;
- if (IS_ERR(dev->power.qos))
+ if (IS_ERR_OR_NULL(dev->power.qos))
ret = -ENODEV;
- else if (!dev->power.qos)
- ret = dev_pm_qos_constraints_allocate(dev);
trace_dev_pm_qos_add_request(dev_name(dev), type, value);
if (ret)
@@ -390,6 +410,10 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
{
int ret;
+ ret = dev_pm_qos_constraints_ensure_allocated(dev);
+ if (ret)
+ return ret;
+
mutex_lock(&dev_pm_qos_mtx);
ret = __dev_pm_qos_add_request(dev, req, type, value);
mutex_unlock(&dev_pm_qos_mtx);
@@ -537,15 +561,11 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
{
int ret = 0;
- mutex_lock(&dev_pm_qos_mtx);
-
- if (IS_ERR(dev->power.qos))
- ret = -ENODEV;
- else if (!dev->power.qos)
- ret = dev_pm_qos_constraints_allocate(dev);
-
+ ret = dev_pm_qos_constraints_ensure_allocated(dev);
if (ret)
- goto unlock;
+ return ret;
+
+ mutex_lock(&dev_pm_qos_mtx);
switch (type) {
case DEV_PM_QOS_RESUME_LATENCY:
@@ -565,7 +585,6 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
ret = -EINVAL;
}
-unlock:
mutex_unlock(&dev_pm_qos_mtx);
return ret;
}
@@ -905,10 +924,13 @@ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
{
int ret;
+ ret = dev_pm_qos_constraints_ensure_allocated(dev);
+ if (ret)
+ return ret;
+
mutex_lock(&dev_pm_qos_mtx);
- if (IS_ERR_OR_NULL(dev->power.qos)
- || !dev->power.qos->latency_tolerance_req) {
+ if (!dev->power.qos->latency_tolerance_req) {
struct dev_pm_qos_request *req;
if (val < 0) {
--
2.39.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
` (2 preceding siblings ...)
2023-03-20 14:43 ` [PATCH v2 17/23] PM / QoS: Fix constraints alloc vs reclaim locking Rob Clark
@ 2023-03-20 14:43 ` Rob Clark
2023-03-20 20:13 ` kernel test robot
` (2 more replies)
2023-03-20 14:43 ` [PATCH v2 19/23] PM / QoS: Teach lockdep about dev_pm_qos_mtx locking order Rob Clark
` (3 subsequent siblings)
7 siblings, 3 replies; 14+ messages in thread
From: Rob Clark @ 2023-03-20 14:43 UTC (permalink / raw)
To: dri-devel
Cc: Daniel Vetter, freedreno, linux-arm-msm, Rob Clark,
Rafael J. Wysocki, Len Brown, Pavel Machek, Greg Kroah-Hartman,
open list:POWER MANAGEMENT CORE, open list
From: Rob Clark <robdclark@chromium.org>
Similar to the previous patch, move the allocation out from under
dev_pm_qos_mtx, by speculatively doing the allocation and handle
any race after acquiring dev_pm_qos_mtx by freeing the redundant
allocation.
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/base/power/qos.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index f3e0c6b65635..9cba334b3729 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -922,12 +922,16 @@ s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
*/
int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
{
+ struct dev_pm_qos_request *req = NULL;
int ret;
ret = dev_pm_qos_constraints_ensure_allocated(dev);
if (ret)
return ret;
+ if (!dev->power.qos->latency_tolerance_req)
+ req = kzalloc(sizeof(*req), GFP_KERNEL);
+
mutex_lock(&dev_pm_qos_mtx);
if (!dev->power.qos->latency_tolerance_req) {
@@ -940,7 +944,6 @@ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
ret = -EINVAL;
goto out;
}
- req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req) {
ret = -ENOMEM;
goto out;
@@ -952,6 +955,13 @@ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
}
dev->power.qos->latency_tolerance_req = req;
} else {
+ /*
+ * If we raced with another thread to allocate the request,
+ * simply free the redundant allocation and move on.
+ */
+ if (req)
+ kfree(req);
+
if (val < 0) {
__dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
ret = 0;
--
2.39.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v2 19/23] PM / QoS: Teach lockdep about dev_pm_qos_mtx locking order
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
` (3 preceding siblings ...)
2023-03-20 14:43 ` [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx Rob Clark
@ 2023-03-20 14:43 ` Rob Clark
2023-03-20 14:43 ` [PATCH v2 21/23] interconnect: Fix locking for runpm vs reclaim Rob Clark
` (2 subsequent siblings)
7 siblings, 0 replies; 14+ messages in thread
From: Rob Clark @ 2023-03-20 14:43 UTC (permalink / raw)
To: dri-devel
Cc: Daniel Vetter, freedreno, linux-arm-msm, Rob Clark,
Rafael J. Wysocki, Pavel Machek, Len Brown, Greg Kroah-Hartman,
open list:HIBERNATION (aka Software Suspend, aka swsusp),
open list
From: Rob Clark <robdclark@chromium.org>
Annotate dev_pm_qos_mtx to teach lockdep to scream about allocations
that could trigger reclaim under dev_pm_qos_mtx.
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/base/power/qos.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 9cba334b3729..d4addda3944a 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -1012,3 +1012,14 @@ void dev_pm_qos_hide_latency_tolerance(struct device *dev)
pm_runtime_put(dev);
}
EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);
+
+static int __init dev_pm_qos_init(void)
+{
+ /* Teach lockdep about lock ordering wrt. shrinker: */
+ fs_reclaim_acquire(GFP_KERNEL);
+ might_lock(&dev_pm_qos_mtx);
+ fs_reclaim_release(GFP_KERNEL);
+
+ return 0;
+}
+early_initcall(dev_pm_qos_init);
--
2.39.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v2 21/23] interconnect: Fix locking for runpm vs reclaim
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
` (4 preceding siblings ...)
2023-03-20 14:43 ` [PATCH v2 19/23] PM / QoS: Teach lockdep about dev_pm_qos_mtx locking order Rob Clark
@ 2023-03-20 14:43 ` Rob Clark
2023-03-20 14:43 ` [PATCH v2 22/23] interconnect: Teach lockdep about icc_bw_lock order Rob Clark
2023-04-07 17:41 ` (subset) [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Bjorn Andersson
7 siblings, 0 replies; 14+ messages in thread
From: Rob Clark @ 2023-03-20 14:43 UTC (permalink / raw)
To: dri-devel
Cc: Daniel Vetter, freedreno, linux-arm-msm, Rob Clark,
Georgi Djakov, open list:INTERCONNECT API, open list
From: Rob Clark <robdclark@chromium.org>
For cases where icc_bw_set() can be called in callbaths that could
deadlock against shrinker/reclaim, such as runpm resume, we need to
decouple the icc locking. Introduce a new icc_bw_lock for cases where
we need to serialize bw aggregation and update to decouple that from
paths that require memory allocation such as node/link creation/
destruction.
Fixes this lockdep splat:
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc8-debug+ #554 Not tainted
------------------------------------------------------
ring0/132 is trying to acquire lock:
ffffff80871916d0 (&gmu->lock){+.+.}-{3:3}, at: a6xx_pm_resume+0xf0/0x234
but task is already holding lock:
ffffffdb5aee57e8 (dma_fence_map){++++}-{0:0}, at: msm_job_run+0x68/0x150
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (dma_fence_map){++++}-{0:0}:
__dma_fence_might_wait+0x74/0xc0
dma_resv_lockdep+0x1f4/0x2f4
do_one_initcall+0x104/0x2bc
kernel_init_freeable+0x344/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #3 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}:
fs_reclaim_acquire+0x80/0xa8
slab_pre_alloc_hook.constprop.0+0x40/0x25c
__kmem_cache_alloc_node+0x60/0x1cc
__kmalloc+0xd8/0x100
topology_parse_cpu_capacity+0x8c/0x178
get_cpu_for_node+0x88/0xc4
parse_cluster+0x1b0/0x28c
parse_cluster+0x8c/0x28c
init_cpu_topology+0x168/0x188
smp_prepare_cpus+0x24/0xf8
kernel_init_freeable+0x18c/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #2 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire+0x3c/0x48
fs_reclaim_acquire+0x54/0xa8
slab_pre_alloc_hook.constprop.0+0x40/0x25c
__kmem_cache_alloc_node+0x60/0x1cc
__kmalloc+0xd8/0x100
kzalloc.constprop.0+0x14/0x20
icc_node_create_nolock+0x4c/0xc4
icc_node_create+0x38/0x58
qcom_icc_rpmh_probe+0x1b8/0x248
platform_probe+0x70/0xc4
really_probe+0x158/0x290
__driver_probe_device+0xc8/0xe0
driver_probe_device+0x44/0x100
__driver_attach+0xf8/0x108
bus_for_each_dev+0x78/0xc4
driver_attach+0x2c/0x38
bus_add_driver+0xd0/0x1d8
driver_register+0xbc/0xf8
__platform_driver_register+0x30/0x3c
qnoc_driver_init+0x24/0x30
do_one_initcall+0x104/0x2bc
kernel_init_freeable+0x344/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #1 (icc_lock){+.+.}-{3:3}:
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
icc_set_bw+0x88/0x2b4
_set_opp_bw+0x8c/0xd8
_set_opp+0x19c/0x300
dev_pm_opp_set_opp+0x84/0x94
a6xx_gmu_resume+0x18c/0x804
a6xx_pm_resume+0xf8/0x234
adreno_runtime_resume+0x2c/0x38
pm_generic_runtime_resume+0x30/0x44
__rpm_callback+0x15c/0x174
rpm_callback+0x78/0x7c
rpm_resume+0x318/0x524
__pm_runtime_resume+0x78/0xbc
adreno_load_gpu+0xc4/0x17c
msm_open+0x50/0x120
drm_file_alloc+0x17c/0x228
drm_open_helper+0x74/0x118
drm_open+0xa0/0x144
drm_stub_open+0xd4/0xe4
chrdev_open+0x1b8/0x1e4
do_dentry_open+0x2f8/0x38c
vfs_open+0x34/0x40
path_openat+0x64c/0x7b4
do_filp_open+0x54/0xc4
do_sys_openat2+0x9c/0x100
do_sys_open+0x50/0x7c
__arm64_sys_openat+0x28/0x34
invoke_syscall+0x8c/0x128
el0_svc_common.constprop.0+0xa0/0x11c
do_el0_svc+0xac/0xbc
el0_svc+0x48/0xa0
el0t_64_sync_handler+0xac/0x13c
el0t_64_sync+0x190/0x194
-> #0 (&gmu->lock){+.+.}-{3:3}:
__lock_acquire+0xe00/0x1060
lock_acquire+0x1e0/0x2f8
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
a6xx_pm_resume+0xf0/0x234
adreno_runtime_resume+0x2c/0x38
pm_generic_runtime_resume+0x30/0x44
__rpm_callback+0x15c/0x174
rpm_callback+0x78/0x7c
rpm_resume+0x318/0x524
__pm_runtime_resume+0x78/0xbc
pm_runtime_get_sync.isra.0+0x14/0x20
msm_gpu_submit+0x58/0x178
msm_job_run+0x78/0x150
drm_sched_main+0x290/0x370
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
other info that might help us debug this:
Chain exists of:
&gmu->lock --> mmu_notifier_invalidate_range_start --> dma_fence_map
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(dma_fence_map);
lock(mmu_notifier_invalidate_range_start);
lock(dma_fence_map);
lock(&gmu->lock);
*** DEADLOCK ***
2 locks held by ring0/132:
#0: ffffff8087191170 (&gpu->lock){+.+.}-{3:3}, at: msm_job_run+0x64/0x150
#1: ffffffdb5aee57e8 (dma_fence_map){++++}-{0:0}, at: msm_job_run+0x68/0x150
stack backtrace:
CPU: 7 PID: 132 Comm: ring0 Not tainted 6.2.0-rc8-debug+ #554
Hardware name: Google Lazor (rev1 - 2) with LTE (DT)
Call trace:
dump_backtrace.part.0+0xb4/0xf8
show_stack+0x20/0x38
dump_stack_lvl+0x9c/0xd0
dump_stack+0x18/0x34
print_circular_bug+0x1b4/0x1f0
check_noncircular+0x78/0xac
__lock_acquire+0xe00/0x1060
lock_acquire+0x1e0/0x2f8
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
a6xx_pm_resume+0xf0/0x234
adreno_runtime_resume+0x2c/0x38
pm_generic_runtime_resume+0x30/0x44
__rpm_callback+0x15c/0x174
rpm_callback+0x78/0x7c
rpm_resume+0x318/0x524
__pm_runtime_resume+0x78/0xbc
pm_runtime_get_sync.isra.0+0x14/0x20
msm_gpu_submit+0x58/0x178
msm_job_run+0x78/0x150
drm_sched_main+0x290/0x370
kthread+0xf0/0x100
ret_from_fork+0x10/0x20
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/interconnect/core.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index 25debded65a8..f7251784765f 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -29,6 +29,7 @@ static LIST_HEAD(icc_providers);
static int providers_count;
static bool synced_state;
static DEFINE_MUTEX(icc_lock);
+static DEFINE_MUTEX(icc_bw_lock);
static struct dentry *icc_debugfs_dir;
static void icc_summary_show_one(struct seq_file *s, struct icc_node *n)
@@ -632,7 +633,7 @@ int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
if (WARN_ON(IS_ERR(path) || !path->num_nodes))
return -EINVAL;
- mutex_lock(&icc_lock);
+ mutex_lock(&icc_bw_lock);
old_avg = path->reqs[0].avg_bw;
old_peak = path->reqs[0].peak_bw;
@@ -664,7 +665,7 @@ int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
apply_constraints(path);
}
- mutex_unlock(&icc_lock);
+ mutex_unlock(&icc_bw_lock);
trace_icc_set_bw_end(path, ret);
@@ -963,6 +964,7 @@ void icc_node_add(struct icc_node *node, struct icc_provider *provider)
return;
mutex_lock(&icc_lock);
+ mutex_lock(&icc_bw_lock);
node->provider = provider;
list_add_tail(&node->node_list, &provider->nodes);
@@ -988,6 +990,7 @@ void icc_node_add(struct icc_node *node, struct icc_provider *provider)
node->avg_bw = 0;
node->peak_bw = 0;
+ mutex_unlock(&icc_bw_lock);
mutex_unlock(&icc_lock);
}
EXPORT_SYMBOL_GPL(icc_node_add);
@@ -1111,6 +1114,7 @@ void icc_sync_state(struct device *dev)
return;
mutex_lock(&icc_lock);
+ mutex_lock(&icc_bw_lock);
synced_state = true;
list_for_each_entry(p, &icc_providers, provider_list) {
dev_dbg(p->dev, "interconnect provider is in synced state\n");
--
2.39.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v2 22/23] interconnect: Teach lockdep about icc_bw_lock order
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
` (5 preceding siblings ...)
2023-03-20 14:43 ` [PATCH v2 21/23] interconnect: Fix locking for runpm vs reclaim Rob Clark
@ 2023-03-20 14:43 ` Rob Clark
2023-04-07 17:41 ` (subset) [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Bjorn Andersson
7 siblings, 0 replies; 14+ messages in thread
From: Rob Clark @ 2023-03-20 14:43 UTC (permalink / raw)
To: dri-devel
Cc: Daniel Vetter, freedreno, linux-arm-msm, Rob Clark,
Georgi Djakov, open list:INTERCONNECT API, open list
From: Rob Clark <robdclark@chromium.org>
Teach lockdep that icc_bw_lock is needed in code paths that could
deadlock if they trigger reclaim.
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/interconnect/core.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index f7251784765f..5619963ee85c 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -1127,13 +1127,21 @@ void icc_sync_state(struct device *dev)
}
}
}
+ mutex_unlock(&icc_bw_lock);
mutex_unlock(&icc_lock);
}
EXPORT_SYMBOL_GPL(icc_sync_state);
static int __init icc_init(void)
{
- struct device_node *root = of_find_node_by_path("/");
+ struct device_node *root;
+
+ /* Teach lockdep about lock ordering wrt. shrinker: */
+ fs_reclaim_acquire(GFP_KERNEL);
+ might_lock(&icc_bw_lock);
+ fs_reclaim_release(GFP_KERNEL);
+
+ root = of_find_node_by_path("/");
providers_count = of_count_icc_providers(root);
of_node_put(root);
--
2.39.2
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx
2023-03-20 14:43 ` [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx Rob Clark
@ 2023-03-20 20:13 ` kernel test robot
2023-03-20 20:34 ` kernel test robot
2023-03-21 4:53 ` Dan Carpenter
2 siblings, 0 replies; 14+ messages in thread
From: kernel test robot @ 2023-03-20 20:13 UTC (permalink / raw)
To: Rob Clark, dri-devel
Cc: llvm, oe-kbuild-all, Rob Clark, Len Brown, Pavel Machek,
Rafael J. Wysocki, linux-arm-msm,
open list:POWER MANAGEMENT CORE, open list, Greg Kroah-Hartman,
freedreno
Hi Rob,
I love your patch! Perhaps something to improve:
[auto build test WARNING on drm-misc/drm-misc-next]
[also build test WARNING on rafael-pm/linux-next drm-intel/for-linux-next drm-intel/for-linux-next-fixes drm-tip/drm-tip linus/master v6.3-rc3 next-20230320]
[cannot apply to chanwoo/devfreq-testing]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Rob-Clark/drm-msm-Pre-allocate-hw_fence/20230320-224826
base: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
patch link: https://lore.kernel.org/r/20230320144356.803762-19-robdclark%40gmail.com
patch subject: [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx
config: arm-randconfig-r005-20230319 (https://download.01.org/0day-ci/archive/20230321/202303210444.Qtybv08z-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm cross compiling tool for clang build
# apt-get install binutils-arm-linux-gnueabi
# https://github.com/intel-lab-lkp/linux/commit/2d7e4629d7265d7e77fc72d01e84d27d805b7485
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Rob-Clark/drm-msm-Pre-allocate-hw_fence/20230320-224826
git checkout 2d7e4629d7265d7e77fc72d01e84d27d805b7485
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/base/power/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303210444.Qtybv08z-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/base/power/qos.c:947:8: warning: variable 'req' is uninitialized when used here [-Wuninitialized]
if (!req) {
^~~
drivers/base/power/qos.c:938:33: note: initialize the variable 'req' to silence this warning
struct dev_pm_qos_request *req;
^
= NULL
1 warning generated.
vim +/req +947 drivers/base/power/qos.c
2d984ad132a87c Rafael J. Wysocki 2014-02-11 917
2d984ad132a87c Rafael J. Wysocki 2014-02-11 918 /**
2d984ad132a87c Rafael J. Wysocki 2014-02-11 919 * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
2d984ad132a87c Rafael J. Wysocki 2014-02-11 920 * @dev: Device to update the user space latency tolerance for.
2d984ad132a87c Rafael J. Wysocki 2014-02-11 921 * @val: New user space latency tolerance for @dev (negative values disable).
2d984ad132a87c Rafael J. Wysocki 2014-02-11 922 */
2d984ad132a87c Rafael J. Wysocki 2014-02-11 923 int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
2d984ad132a87c Rafael J. Wysocki 2014-02-11 924 {
2d7e4629d7265d Rob Clark 2023-03-20 925 struct dev_pm_qos_request *req = NULL;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 926 int ret;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 927
00dd582e52a535 Rob Clark 2023-03-20 928 ret = dev_pm_qos_constraints_ensure_allocated(dev);
00dd582e52a535 Rob Clark 2023-03-20 929 if (ret)
00dd582e52a535 Rob Clark 2023-03-20 930 return ret;
00dd582e52a535 Rob Clark 2023-03-20 931
2d7e4629d7265d Rob Clark 2023-03-20 932 if (!dev->power.qos->latency_tolerance_req)
2d7e4629d7265d Rob Clark 2023-03-20 933 req = kzalloc(sizeof(*req), GFP_KERNEL);
2d7e4629d7265d Rob Clark 2023-03-20 934
2d984ad132a87c Rafael J. Wysocki 2014-02-11 935 mutex_lock(&dev_pm_qos_mtx);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 936
00dd582e52a535 Rob Clark 2023-03-20 937 if (!dev->power.qos->latency_tolerance_req) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 938 struct dev_pm_qos_request *req;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 939
2d984ad132a87c Rafael J. Wysocki 2014-02-11 940 if (val < 0) {
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 941 if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 942 ret = 0;
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 943 else
2d984ad132a87c Rafael J. Wysocki 2014-02-11 944 ret = -EINVAL;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 945 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 946 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 @947 if (!req) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 948 ret = -ENOMEM;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 949 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 950 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 951 ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 952 if (ret < 0) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 953 kfree(req);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 954 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 955 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 956 dev->power.qos->latency_tolerance_req = req;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 957 } else {
2d7e4629d7265d Rob Clark 2023-03-20 958 /*
2d7e4629d7265d Rob Clark 2023-03-20 959 * If we raced with another thread to allocate the request,
2d7e4629d7265d Rob Clark 2023-03-20 960 * simply free the redundant allocation and move on.
2d7e4629d7265d Rob Clark 2023-03-20 961 */
2d7e4629d7265d Rob Clark 2023-03-20 962 if (req)
2d7e4629d7265d Rob Clark 2023-03-20 963 kfree(req);
2d7e4629d7265d Rob Clark 2023-03-20 964
2d984ad132a87c Rafael J. Wysocki 2014-02-11 965 if (val < 0) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 966 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 967 ret = 0;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 968 } else {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 969 ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 970 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 971 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 972
2d984ad132a87c Rafael J. Wysocki 2014-02-11 973 out:
2d984ad132a87c Rafael J. Wysocki 2014-02-11 974 mutex_unlock(&dev_pm_qos_mtx);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 975 return ret;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 976 }
034e7906211c18 Andrew Lutomirski 2016-11-29 977 EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance);
13b2c4a0c3b1cd Mika Westerberg 2015-07-27 978
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx
2023-03-20 14:43 ` [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx Rob Clark
2023-03-20 20:13 ` kernel test robot
@ 2023-03-20 20:34 ` kernel test robot
2023-03-21 4:53 ` Dan Carpenter
2 siblings, 0 replies; 14+ messages in thread
From: kernel test robot @ 2023-03-20 20:34 UTC (permalink / raw)
To: Rob Clark, dri-devel
Cc: llvm, oe-kbuild-all, Rob Clark, Len Brown, Pavel Machek,
Rafael J. Wysocki, linux-arm-msm,
open list:POWER MANAGEMENT CORE, open list, Greg Kroah-Hartman,
freedreno
Hi Rob,
I love your patch! Perhaps something to improve:
[auto build test WARNING on drm-misc/drm-misc-next]
[also build test WARNING on rafael-pm/linux-next drm-intel/for-linux-next drm-intel/for-linux-next-fixes drm-tip/drm-tip linus/master v6.3-rc3 next-20230320]
[cannot apply to chanwoo/devfreq-testing]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Rob-Clark/drm-msm-Pre-allocate-hw_fence/20230320-224826
base: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
patch link: https://lore.kernel.org/r/20230320144356.803762-19-robdclark%40gmail.com
patch subject: [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx
config: x86_64-randconfig-a014 (https://download.01.org/0day-ci/archive/20230321/202303210420.9g2z6MgO-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/2d7e4629d7265d7e77fc72d01e84d27d805b7485
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Rob-Clark/drm-msm-Pre-allocate-hw_fence/20230320-224826
git checkout 2d7e4629d7265d7e77fc72d01e84d27d805b7485
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/base/power/ drivers/char/tpm/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303210420.9g2z6MgO-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/base/power/qos.c:947:8: warning: variable 'req' is uninitialized when used here [-Wuninitialized]
if (!req) {
^~~
drivers/base/power/qos.c:938:33: note: initialize the variable 'req' to silence this warning
struct dev_pm_qos_request *req;
^
= NULL
1 warning generated.
vim +/req +947 drivers/base/power/qos.c
2d984ad132a87c Rafael J. Wysocki 2014-02-11 917
2d984ad132a87c Rafael J. Wysocki 2014-02-11 918 /**
2d984ad132a87c Rafael J. Wysocki 2014-02-11 919 * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
2d984ad132a87c Rafael J. Wysocki 2014-02-11 920 * @dev: Device to update the user space latency tolerance for.
2d984ad132a87c Rafael J. Wysocki 2014-02-11 921 * @val: New user space latency tolerance for @dev (negative values disable).
2d984ad132a87c Rafael J. Wysocki 2014-02-11 922 */
2d984ad132a87c Rafael J. Wysocki 2014-02-11 923 int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
2d984ad132a87c Rafael J. Wysocki 2014-02-11 924 {
2d7e4629d7265d Rob Clark 2023-03-20 925 struct dev_pm_qos_request *req = NULL;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 926 int ret;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 927
00dd582e52a535 Rob Clark 2023-03-20 928 ret = dev_pm_qos_constraints_ensure_allocated(dev);
00dd582e52a535 Rob Clark 2023-03-20 929 if (ret)
00dd582e52a535 Rob Clark 2023-03-20 930 return ret;
00dd582e52a535 Rob Clark 2023-03-20 931
2d7e4629d7265d Rob Clark 2023-03-20 932 if (!dev->power.qos->latency_tolerance_req)
2d7e4629d7265d Rob Clark 2023-03-20 933 req = kzalloc(sizeof(*req), GFP_KERNEL);
2d7e4629d7265d Rob Clark 2023-03-20 934
2d984ad132a87c Rafael J. Wysocki 2014-02-11 935 mutex_lock(&dev_pm_qos_mtx);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 936
00dd582e52a535 Rob Clark 2023-03-20 937 if (!dev->power.qos->latency_tolerance_req) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 938 struct dev_pm_qos_request *req;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 939
2d984ad132a87c Rafael J. Wysocki 2014-02-11 940 if (val < 0) {
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 941 if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 942 ret = 0;
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 943 else
2d984ad132a87c Rafael J. Wysocki 2014-02-11 944 ret = -EINVAL;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 945 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 946 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 @947 if (!req) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 948 ret = -ENOMEM;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 949 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 950 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 951 ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 952 if (ret < 0) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 953 kfree(req);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 954 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 955 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 956 dev->power.qos->latency_tolerance_req = req;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 957 } else {
2d7e4629d7265d Rob Clark 2023-03-20 958 /*
2d7e4629d7265d Rob Clark 2023-03-20 959 * If we raced with another thread to allocate the request,
2d7e4629d7265d Rob Clark 2023-03-20 960 * simply free the redundant allocation and move on.
2d7e4629d7265d Rob Clark 2023-03-20 961 */
2d7e4629d7265d Rob Clark 2023-03-20 962 if (req)
2d7e4629d7265d Rob Clark 2023-03-20 963 kfree(req);
2d7e4629d7265d Rob Clark 2023-03-20 964
2d984ad132a87c Rafael J. Wysocki 2014-02-11 965 if (val < 0) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 966 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 967 ret = 0;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 968 } else {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 969 ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 970 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 971 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 972
2d984ad132a87c Rafael J. Wysocki 2014-02-11 973 out:
2d984ad132a87c Rafael J. Wysocki 2014-02-11 974 mutex_unlock(&dev_pm_qos_mtx);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 975 return ret;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 976 }
034e7906211c18 Andrew Lutomirski 2016-11-29 977 EXPORT_SYMBOL_GPL(dev_pm_qos_update_user_latency_tolerance);
13b2c4a0c3b1cd Mika Westerberg 2015-07-27 978
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx
2023-03-20 14:43 ` [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx Rob Clark
2023-03-20 20:13 ` kernel test robot
2023-03-20 20:34 ` kernel test robot
@ 2023-03-21 4:53 ` Dan Carpenter
2 siblings, 0 replies; 14+ messages in thread
From: Dan Carpenter @ 2023-03-21 4:53 UTC (permalink / raw)
To: oe-kbuild, Rob Clark, dri-devel
Cc: lkp, oe-kbuild-all, Rob Clark, Len Brown, Pavel Machek,
Rafael J. Wysocki, linux-arm-msm,
open list:POWER MANAGEMENT CORE, open list, Greg Kroah-Hartman,
freedreno
Hi Rob,
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Rob-Clark/drm-msm-Pre-allocate-hw_fence/20230320-224826
base: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
patch link: https://lore.kernel.org/r/20230320144356.803762-19-robdclark%40gmail.com
patch subject: [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx
config: arm64-randconfig-m041-20230319 (https://download.01.org/0day-ci/archive/20230321/202303211207.mUCSt3CK-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 12.1.0
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Link: https://lore.kernel.org/r/202303211207.mUCSt3CK-lkp@intel.com/
smatch warnings:
drivers/base/power/qos.c:947 dev_pm_qos_update_user_latency_tolerance() error: uninitialized symbol 'req'.
drivers/base/power/qos.c:975 dev_pm_qos_update_user_latency_tolerance() warn: possible memory leak of 'req'
vim +/req +947 drivers/base/power/qos.c
2d984ad132a87c Rafael J. Wysocki 2014-02-11 923 int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
2d984ad132a87c Rafael J. Wysocki 2014-02-11 924 {
2d7e4629d7265d Rob Clark 2023-03-20 925 struct dev_pm_qos_request *req = NULL;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 926 int ret;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 927
00dd582e52a535 Rob Clark 2023-03-20 928 ret = dev_pm_qos_constraints_ensure_allocated(dev);
00dd582e52a535 Rob Clark 2023-03-20 929 if (ret)
00dd582e52a535 Rob Clark 2023-03-20 930 return ret;
00dd582e52a535 Rob Clark 2023-03-20 931
2d7e4629d7265d Rob Clark 2023-03-20 932 if (!dev->power.qos->latency_tolerance_req)
2d7e4629d7265d Rob Clark 2023-03-20 933 req = kzalloc(sizeof(*req), GFP_KERNEL);
2d7e4629d7265d Rob Clark 2023-03-20 934
2d984ad132a87c Rafael J. Wysocki 2014-02-11 935 mutex_lock(&dev_pm_qos_mtx);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 936
00dd582e52a535 Rob Clark 2023-03-20 937 if (!dev->power.qos->latency_tolerance_req) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 938 struct dev_pm_qos_request *req;
This "req" shadows the ealier req.
2d984ad132a87c Rafael J. Wysocki 2014-02-11 939
2d984ad132a87c Rafael J. Wysocki 2014-02-11 940 if (val < 0) {
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 941 if (val == PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT)
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 942 ret = 0;
80a6f7c79b7822 Andrew Lutomirski 2016-11-29 943 else
2d984ad132a87c Rafael J. Wysocki 2014-02-11 944 ret = -EINVAL;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 945 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 946 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 @947 if (!req) {
So it leads to an unintialized variable and a leak.
2d984ad132a87c Rafael J. Wysocki 2014-02-11 948 ret = -ENOMEM;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 949 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 950 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 951 ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 952 if (ret < 0) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 953 kfree(req);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 954 goto out;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 955 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 956 dev->power.qos->latency_tolerance_req = req;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 957 } else {
2d7e4629d7265d Rob Clark 2023-03-20 958 /*
2d7e4629d7265d Rob Clark 2023-03-20 959 * If we raced with another thread to allocate the request,
2d7e4629d7265d Rob Clark 2023-03-20 960 * simply free the redundant allocation and move on.
2d7e4629d7265d Rob Clark 2023-03-20 961 */
2d7e4629d7265d Rob Clark 2023-03-20 962 if (req)
2d7e4629d7265d Rob Clark 2023-03-20 963 kfree(req);
2d7e4629d7265d Rob Clark 2023-03-20 964
2d984ad132a87c Rafael J. Wysocki 2014-02-11 965 if (val < 0) {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 966 __dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 967 ret = 0;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 968 } else {
2d984ad132a87c Rafael J. Wysocki 2014-02-11 969 ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 970 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 971 }
2d984ad132a87c Rafael J. Wysocki 2014-02-11 972
2d984ad132a87c Rafael J. Wysocki 2014-02-11 973 out:
2d984ad132a87c Rafael J. Wysocki 2014-02-11 974 mutex_unlock(&dev_pm_qos_mtx);
2d984ad132a87c Rafael J. Wysocki 2014-02-11 @975 return ret;
2d984ad132a87c Rafael J. Wysocki 2014-02-11 976 }
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v2 17/23] PM / QoS: Fix constraints alloc vs reclaim locking
2023-03-20 14:43 ` [PATCH v2 17/23] PM / QoS: Fix constraints alloc vs reclaim locking Rob Clark
@ 2023-03-27 17:53 ` Rafael J. Wysocki
2023-03-27 19:52 ` Rob Clark
0 siblings, 1 reply; 14+ messages in thread
From: Rafael J. Wysocki @ 2023-03-27 17:53 UTC (permalink / raw)
To: Rob Clark
Cc: dri-devel, Daniel Vetter, freedreno, linux-arm-msm, Rob Clark,
Rafael J. Wysocki, Pavel Machek, Len Brown, Greg Kroah-Hartman,
open list:HIBERNATION (aka Software Suspend, aka swsusp),
open list
On Mon, Mar 20, 2023 at 3:45 PM Rob Clark <robdclark@gmail.com> wrote:
>
> From: Rob Clark <robdclark@chromium.org>
>
> In the process of adding lockdep annotation for drm GPU scheduler's
> job_run() to detect potential deadlock against shrinker/reclaim, I hit
> this lockdep splat:
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.2.0-rc8-debug+ #558 Tainted: G W
> ------------------------------------------------------
> ring0/125 is trying to acquire lock:
> ffffffd6d6ce0f28 (dev_pm_qos_mtx){+.+.}-{3:3}, at: dev_pm_qos_update_request+0x38/0x68
>
> but task is already holding lock:
> ffffff8087239208 (&gpu->active_lock){+.+.}-{3:3}, at: msm_gpu_submit+0xec/0x178
>
> which lock already depends on the new lock.
>
> the existing dependency chain (in reverse order) is:
>
> -> #4 (&gpu->active_lock){+.+.}-{3:3}:
> __mutex_lock+0xcc/0x3c8
> mutex_lock_nested+0x30/0x44
> msm_gpu_submit+0xec/0x178
> msm_job_run+0x78/0x150
> drm_sched_main+0x290/0x370
> kthread+0xf0/0x100
> ret_from_fork+0x10/0x20
>
> -> #3 (dma_fence_map){++++}-{0:0}:
> __dma_fence_might_wait+0x74/0xc0
> dma_resv_lockdep+0x1f4/0x2f4
> do_one_initcall+0x104/0x2bc
> kernel_init_freeable+0x344/0x34c
> kernel_init+0x30/0x134
> ret_from_fork+0x10/0x20
>
> -> #2 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}:
> fs_reclaim_acquire+0x80/0xa8
> slab_pre_alloc_hook.constprop.0+0x40/0x25c
> __kmem_cache_alloc_node+0x60/0x1cc
> __kmalloc+0xd8/0x100
> topology_parse_cpu_capacity+0x8c/0x178
> get_cpu_for_node+0x88/0xc4
> parse_cluster+0x1b0/0x28c
> parse_cluster+0x8c/0x28c
> init_cpu_topology+0x168/0x188
> smp_prepare_cpus+0x24/0xf8
> kernel_init_freeable+0x18c/0x34c
> kernel_init+0x30/0x134
> ret_from_fork+0x10/0x20
>
> -> #1 (fs_reclaim){+.+.}-{0:0}:
> __fs_reclaim_acquire+0x3c/0x48
> fs_reclaim_acquire+0x54/0xa8
> slab_pre_alloc_hook.constprop.0+0x40/0x25c
> __kmem_cache_alloc_node+0x60/0x1cc
> kmalloc_trace+0x50/0xa8
> dev_pm_qos_constraints_allocate+0x38/0x100
> __dev_pm_qos_add_request+0xb0/0x1e8
> dev_pm_qos_add_request+0x58/0x80
> dev_pm_qos_expose_latency_limit+0x60/0x13c
> register_cpu+0x12c/0x130
> topology_init+0xac/0xbc
> do_one_initcall+0x104/0x2bc
> kernel_init_freeable+0x344/0x34c
> kernel_init+0x30/0x134
> ret_from_fork+0x10/0x20
>
> -> #0 (dev_pm_qos_mtx){+.+.}-{3:3}:
> __lock_acquire+0xe00/0x1060
> lock_acquire+0x1e0/0x2f8
> __mutex_lock+0xcc/0x3c8
> mutex_lock_nested+0x30/0x44
> dev_pm_qos_update_request+0x38/0x68
> msm_devfreq_boost+0x40/0x70
> msm_devfreq_active+0xc0/0xf0
> msm_gpu_submit+0x10c/0x178
> msm_job_run+0x78/0x150
> drm_sched_main+0x290/0x370
> kthread+0xf0/0x100
> ret_from_fork+0x10/0x20
>
> other info that might help us debug this:
>
> Chain exists of:
> dev_pm_qos_mtx --> dma_fence_map --> &gpu->active_lock
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(&gpu->active_lock);
> lock(dma_fence_map);
> lock(&gpu->active_lock);
> lock(dev_pm_qos_mtx);
>
> *** DEADLOCK ***
>
> 3 locks held by ring0/123:
> #0: ffffff8087251170 (&gpu->lock){+.+.}-{3:3}, at: msm_job_run+0x64/0x150
> #1: ffffffd00b0e57e8 (dma_fence_map){++++}-{0:0}, at: msm_job_run+0x68/0x150
> #2: ffffff8087251208 (&gpu->active_lock){+.+.}-{3:3}, at: msm_gpu_submit+0xec/0x178
>
> stack backtrace:
> CPU: 6 PID: 123 Comm: ring0 Not tainted 6.2.0-rc8-debug+ #559
> Hardware name: Google Lazor (rev1 - 2) with LTE (DT)
> Call trace:
> dump_backtrace.part.0+0xb4/0xf8
> show_stack+0x20/0x38
> dump_stack_lvl+0x9c/0xd0
> dump_stack+0x18/0x34
> print_circular_bug+0x1b4/0x1f0
> check_noncircular+0x78/0xac
> __lock_acquire+0xe00/0x1060
> lock_acquire+0x1e0/0x2f8
> __mutex_lock+0xcc/0x3c8
> mutex_lock_nested+0x30/0x44
> dev_pm_qos_update_request+0x38/0x68
> msm_devfreq_boost+0x40/0x70
> msm_devfreq_active+0xc0/0xf0
> msm_gpu_submit+0x10c/0x178
> msm_job_run+0x78/0x150
> drm_sched_main+0x290/0x370
> kthread+0xf0/0x100
> ret_from_fork+0x10/0x20
>
> The issue is that dev_pm_qos_mtx is held in the runpm suspend/resume (or
> freq change) path, but it is also held across allocations that could
> recurse into shrinker.
>
> Solve this by changing dev_pm_qos_constraints_allocate() into a function
> that can be called unconditionally before the device qos object is
> needed and before aquiring dev_pm_qos_mtx. This way the allocations can
> be done without holding the mutex. In the case that we raced with
> another thread to allocate the qos object, detect this *after* acquiring
> the dev_pm_qos_mtx and simply free the redundant allocations.
Honestly, I don't like this approach.
In particular, dropping a lock just in order to grab it again right
away is really confusing (and I'm not even sure it is correct ATM).
Let me think about how to possibly address the issue at hand in a different way.
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
> drivers/base/power/qos.c | 60 +++++++++++++++++++++++++++-------------
> 1 file changed, 41 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
> index 8e93167f1783..f3e0c6b65635 100644
> --- a/drivers/base/power/qos.c
> +++ b/drivers/base/power/qos.c
> @@ -185,18 +185,24 @@ static int apply_constraint(struct dev_pm_qos_request *req,
> }
>
> /*
> - * dev_pm_qos_constraints_allocate
> + * dev_pm_qos_constraints_ensure_allocated
> * @dev: device to allocate data for
> *
> - * Called at the first call to add_request, for constraint data allocation
> - * Must be called with the dev_pm_qos_mtx mutex held
> + * Called to ensure that devices qos is allocated, before acquiring
> + * dev_pm_qos_mtx.
> */
> -static int dev_pm_qos_constraints_allocate(struct device *dev)
> +static int dev_pm_qos_constraints_ensure_allocated(struct device *dev)
> {
> struct dev_pm_qos *qos;
> struct pm_qos_constraints *c;
> struct blocking_notifier_head *n;
>
> + if (!dev)
> + return -ENODEV;
> +
> + if (!IS_ERR_OR_NULL(dev->power.qos))
> + return 0;
> +
> qos = kzalloc(sizeof(*qos), GFP_KERNEL);
> if (!qos)
> return -ENOMEM;
> @@ -227,10 +233,26 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
>
> INIT_LIST_HEAD(&qos->flags.list);
>
> + mutex_lock(&dev_pm_qos_mtx);
> +
> + if (!IS_ERR_OR_NULL(dev->power.qos)) {
> + /*
> + * We have raced with another task to create the qos.
> + * No biggie, just free the resources we've allocated
> + * outside of dev_pm_qos_mtx and move on with life.
> + */
> + kfree(n);
> + kfree(qos);
> + goto unlock;
> + }
> +
> spin_lock_irq(&dev->power.lock);
> dev->power.qos = qos;
> spin_unlock_irq(&dev->power.lock);
>
> +unlock:
> + mutex_unlock(&dev_pm_qos_mtx);
> +
> return 0;
> }
>
> @@ -331,17 +353,15 @@ static int __dev_pm_qos_add_request(struct device *dev,
> {
> int ret = 0;
>
> - if (!dev || !req || dev_pm_qos_invalid_req_type(dev, type))
> + if (!req || dev_pm_qos_invalid_req_type(dev, type))
> return -EINVAL;
>
> if (WARN(dev_pm_qos_request_active(req),
> "%s() called for already added request\n", __func__))
> return -EINVAL;
>
> - if (IS_ERR(dev->power.qos))
> + if (IS_ERR_OR_NULL(dev->power.qos))
> ret = -ENODEV;
> - else if (!dev->power.qos)
> - ret = dev_pm_qos_constraints_allocate(dev);
>
> trace_dev_pm_qos_add_request(dev_name(dev), type, value);
> if (ret)
> @@ -390,6 +410,10 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
> {
> int ret;
>
> + ret = dev_pm_qos_constraints_ensure_allocated(dev);
> + if (ret)
> + return ret;
> +
> mutex_lock(&dev_pm_qos_mtx);
> ret = __dev_pm_qos_add_request(dev, req, type, value);
> mutex_unlock(&dev_pm_qos_mtx);
> @@ -537,15 +561,11 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
> {
> int ret = 0;
>
> - mutex_lock(&dev_pm_qos_mtx);
> -
> - if (IS_ERR(dev->power.qos))
> - ret = -ENODEV;
> - else if (!dev->power.qos)
> - ret = dev_pm_qos_constraints_allocate(dev);
> -
> + ret = dev_pm_qos_constraints_ensure_allocated(dev);
> if (ret)
> - goto unlock;
> + return ret;
> +
> + mutex_lock(&dev_pm_qos_mtx);
>
> switch (type) {
> case DEV_PM_QOS_RESUME_LATENCY:
> @@ -565,7 +585,6 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
> ret = -EINVAL;
> }
>
> -unlock:
> mutex_unlock(&dev_pm_qos_mtx);
> return ret;
> }
> @@ -905,10 +924,13 @@ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
> {
> int ret;
>
> + ret = dev_pm_qos_constraints_ensure_allocated(dev);
> + if (ret)
> + return ret;
> +
> mutex_lock(&dev_pm_qos_mtx);
>
> - if (IS_ERR_OR_NULL(dev->power.qos)
> - || !dev->power.qos->latency_tolerance_req) {
> + if (!dev->power.qos->latency_tolerance_req) {
> struct dev_pm_qos_request *req;
>
> if (val < 0) {
> --
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v2 17/23] PM / QoS: Fix constraints alloc vs reclaim locking
2023-03-27 17:53 ` Rafael J. Wysocki
@ 2023-03-27 19:52 ` Rob Clark
0 siblings, 0 replies; 14+ messages in thread
From: Rob Clark @ 2023-03-27 19:52 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: dri-devel, Daniel Vetter, freedreno, linux-arm-msm, Rob Clark,
Pavel Machek, Len Brown, Greg Kroah-Hartman,
open list:HIBERNATION (aka Software Suspend, aka swsusp),
open list
On Mon, Mar 27, 2023 at 10:53 AM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> On Mon, Mar 20, 2023 at 3:45 PM Rob Clark <robdclark@gmail.com> wrote:
> >
> > From: Rob Clark <robdclark@chromium.org>
> >
> > In the process of adding lockdep annotation for drm GPU scheduler's
> > job_run() to detect potential deadlock against shrinker/reclaim, I hit
> > this lockdep splat:
> >
> > ======================================================
> > WARNING: possible circular locking dependency detected
> > 6.2.0-rc8-debug+ #558 Tainted: G W
> > ------------------------------------------------------
> > ring0/125 is trying to acquire lock:
> > ffffffd6d6ce0f28 (dev_pm_qos_mtx){+.+.}-{3:3}, at: dev_pm_qos_update_request+0x38/0x68
> >
> > but task is already holding lock:
> > ffffff8087239208 (&gpu->active_lock){+.+.}-{3:3}, at: msm_gpu_submit+0xec/0x178
> >
> > which lock already depends on the new lock.
> >
> > the existing dependency chain (in reverse order) is:
> >
> > -> #4 (&gpu->active_lock){+.+.}-{3:3}:
> > __mutex_lock+0xcc/0x3c8
> > mutex_lock_nested+0x30/0x44
> > msm_gpu_submit+0xec/0x178
> > msm_job_run+0x78/0x150
> > drm_sched_main+0x290/0x370
> > kthread+0xf0/0x100
> > ret_from_fork+0x10/0x20
> >
> > -> #3 (dma_fence_map){++++}-{0:0}:
> > __dma_fence_might_wait+0x74/0xc0
> > dma_resv_lockdep+0x1f4/0x2f4
> > do_one_initcall+0x104/0x2bc
> > kernel_init_freeable+0x344/0x34c
> > kernel_init+0x30/0x134
> > ret_from_fork+0x10/0x20
> >
> > -> #2 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}:
> > fs_reclaim_acquire+0x80/0xa8
> > slab_pre_alloc_hook.constprop.0+0x40/0x25c
> > __kmem_cache_alloc_node+0x60/0x1cc
> > __kmalloc+0xd8/0x100
> > topology_parse_cpu_capacity+0x8c/0x178
> > get_cpu_for_node+0x88/0xc4
> > parse_cluster+0x1b0/0x28c
> > parse_cluster+0x8c/0x28c
> > init_cpu_topology+0x168/0x188
> > smp_prepare_cpus+0x24/0xf8
> > kernel_init_freeable+0x18c/0x34c
> > kernel_init+0x30/0x134
> > ret_from_fork+0x10/0x20
> >
> > -> #1 (fs_reclaim){+.+.}-{0:0}:
> > __fs_reclaim_acquire+0x3c/0x48
> > fs_reclaim_acquire+0x54/0xa8
> > slab_pre_alloc_hook.constprop.0+0x40/0x25c
> > __kmem_cache_alloc_node+0x60/0x1cc
> > kmalloc_trace+0x50/0xa8
> > dev_pm_qos_constraints_allocate+0x38/0x100
> > __dev_pm_qos_add_request+0xb0/0x1e8
> > dev_pm_qos_add_request+0x58/0x80
> > dev_pm_qos_expose_latency_limit+0x60/0x13c
> > register_cpu+0x12c/0x130
> > topology_init+0xac/0xbc
> > do_one_initcall+0x104/0x2bc
> > kernel_init_freeable+0x344/0x34c
> > kernel_init+0x30/0x134
> > ret_from_fork+0x10/0x20
> >
> > -> #0 (dev_pm_qos_mtx){+.+.}-{3:3}:
> > __lock_acquire+0xe00/0x1060
> > lock_acquire+0x1e0/0x2f8
> > __mutex_lock+0xcc/0x3c8
> > mutex_lock_nested+0x30/0x44
> > dev_pm_qos_update_request+0x38/0x68
> > msm_devfreq_boost+0x40/0x70
> > msm_devfreq_active+0xc0/0xf0
> > msm_gpu_submit+0x10c/0x178
> > msm_job_run+0x78/0x150
> > drm_sched_main+0x290/0x370
> > kthread+0xf0/0x100
> > ret_from_fork+0x10/0x20
> >
> > other info that might help us debug this:
> >
> > Chain exists of:
> > dev_pm_qos_mtx --> dma_fence_map --> &gpu->active_lock
> >
> > Possible unsafe locking scenario:
> >
> > CPU0 CPU1
> > ---- ----
> > lock(&gpu->active_lock);
> > lock(dma_fence_map);
> > lock(&gpu->active_lock);
> > lock(dev_pm_qos_mtx);
> >
> > *** DEADLOCK ***
> >
> > 3 locks held by ring0/123:
> > #0: ffffff8087251170 (&gpu->lock){+.+.}-{3:3}, at: msm_job_run+0x64/0x150
> > #1: ffffffd00b0e57e8 (dma_fence_map){++++}-{0:0}, at: msm_job_run+0x68/0x150
> > #2: ffffff8087251208 (&gpu->active_lock){+.+.}-{3:3}, at: msm_gpu_submit+0xec/0x178
> >
> > stack backtrace:
> > CPU: 6 PID: 123 Comm: ring0 Not tainted 6.2.0-rc8-debug+ #559
> > Hardware name: Google Lazor (rev1 - 2) with LTE (DT)
> > Call trace:
> > dump_backtrace.part.0+0xb4/0xf8
> > show_stack+0x20/0x38
> > dump_stack_lvl+0x9c/0xd0
> > dump_stack+0x18/0x34
> > print_circular_bug+0x1b4/0x1f0
> > check_noncircular+0x78/0xac
> > __lock_acquire+0xe00/0x1060
> > lock_acquire+0x1e0/0x2f8
> > __mutex_lock+0xcc/0x3c8
> > mutex_lock_nested+0x30/0x44
> > dev_pm_qos_update_request+0x38/0x68
> > msm_devfreq_boost+0x40/0x70
> > msm_devfreq_active+0xc0/0xf0
> > msm_gpu_submit+0x10c/0x178
> > msm_job_run+0x78/0x150
> > drm_sched_main+0x290/0x370
> > kthread+0xf0/0x100
> > ret_from_fork+0x10/0x20
> >
> > The issue is that dev_pm_qos_mtx is held in the runpm suspend/resume (or
> > freq change) path, but it is also held across allocations that could
> > recurse into shrinker.
> >
> > Solve this by changing dev_pm_qos_constraints_allocate() into a function
> > that can be called unconditionally before the device qos object is
> > needed and before aquiring dev_pm_qos_mtx. This way the allocations can
> > be done without holding the mutex. In the case that we raced with
> > another thread to allocate the qos object, detect this *after* acquiring
> > the dev_pm_qos_mtx and simply free the redundant allocations.
>
> Honestly, I don't like this approach.
>
> In particular, dropping a lock just in order to grab it again right
> away is really confusing (and I'm not even sure it is correct ATM).
This patch isn't actually doing that. (And you are right, if it were,
that would be a thing to be suspicious of)
It is just moving the allocations ahead of the locking.
> Let me think about how to possibly address the issue at hand in a different way.
Per device locking would make this easier. But I suppose that gets
into needing ww_mutex when you have things like device_link?
BR,
-R
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> > drivers/base/power/qos.c | 60 +++++++++++++++++++++++++++-------------
> > 1 file changed, 41 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
> > index 8e93167f1783..f3e0c6b65635 100644
> > --- a/drivers/base/power/qos.c
> > +++ b/drivers/base/power/qos.c
> > @@ -185,18 +185,24 @@ static int apply_constraint(struct dev_pm_qos_request *req,
> > }
> >
> > /*
> > - * dev_pm_qos_constraints_allocate
> > + * dev_pm_qos_constraints_ensure_allocated
> > * @dev: device to allocate data for
> > *
> > - * Called at the first call to add_request, for constraint data allocation
> > - * Must be called with the dev_pm_qos_mtx mutex held
> > + * Called to ensure that devices qos is allocated, before acquiring
> > + * dev_pm_qos_mtx.
> > */
> > -static int dev_pm_qos_constraints_allocate(struct device *dev)
> > +static int dev_pm_qos_constraints_ensure_allocated(struct device *dev)
> > {
> > struct dev_pm_qos *qos;
> > struct pm_qos_constraints *c;
> > struct blocking_notifier_head *n;
> >
> > + if (!dev)
> > + return -ENODEV;
> > +
> > + if (!IS_ERR_OR_NULL(dev->power.qos))
> > + return 0;
> > +
> > qos = kzalloc(sizeof(*qos), GFP_KERNEL);
> > if (!qos)
> > return -ENOMEM;
> > @@ -227,10 +233,26 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
> >
> > INIT_LIST_HEAD(&qos->flags.list);
> >
> > + mutex_lock(&dev_pm_qos_mtx);
> > +
> > + if (!IS_ERR_OR_NULL(dev->power.qos)) {
> > + /*
> > + * We have raced with another task to create the qos.
> > + * No biggie, just free the resources we've allocated
> > + * outside of dev_pm_qos_mtx and move on with life.
> > + */
> > + kfree(n);
> > + kfree(qos);
> > + goto unlock;
> > + }
> > +
> > spin_lock_irq(&dev->power.lock);
> > dev->power.qos = qos;
> > spin_unlock_irq(&dev->power.lock);
> >
> > +unlock:
> > + mutex_unlock(&dev_pm_qos_mtx);
> > +
> > return 0;
> > }
> >
> > @@ -331,17 +353,15 @@ static int __dev_pm_qos_add_request(struct device *dev,
> > {
> > int ret = 0;
> >
> > - if (!dev || !req || dev_pm_qos_invalid_req_type(dev, type))
> > + if (!req || dev_pm_qos_invalid_req_type(dev, type))
> > return -EINVAL;
> >
> > if (WARN(dev_pm_qos_request_active(req),
> > "%s() called for already added request\n", __func__))
> > return -EINVAL;
> >
> > - if (IS_ERR(dev->power.qos))
> > + if (IS_ERR_OR_NULL(dev->power.qos))
> > ret = -ENODEV;
> > - else if (!dev->power.qos)
> > - ret = dev_pm_qos_constraints_allocate(dev);
> >
> > trace_dev_pm_qos_add_request(dev_name(dev), type, value);
> > if (ret)
> > @@ -390,6 +410,10 @@ int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
> > {
> > int ret;
> >
> > + ret = dev_pm_qos_constraints_ensure_allocated(dev);
> > + if (ret)
> > + return ret;
> > +
> > mutex_lock(&dev_pm_qos_mtx);
> > ret = __dev_pm_qos_add_request(dev, req, type, value);
> > mutex_unlock(&dev_pm_qos_mtx);
> > @@ -537,15 +561,11 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
> > {
> > int ret = 0;
> >
> > - mutex_lock(&dev_pm_qos_mtx);
> > -
> > - if (IS_ERR(dev->power.qos))
> > - ret = -ENODEV;
> > - else if (!dev->power.qos)
> > - ret = dev_pm_qos_constraints_allocate(dev);
> > -
> > + ret = dev_pm_qos_constraints_ensure_allocated(dev);
> > if (ret)
> > - goto unlock;
> > + return ret;
> > +
> > + mutex_lock(&dev_pm_qos_mtx);
> >
> > switch (type) {
> > case DEV_PM_QOS_RESUME_LATENCY:
> > @@ -565,7 +585,6 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier,
> > ret = -EINVAL;
> > }
> >
> > -unlock:
> > mutex_unlock(&dev_pm_qos_mtx);
> > return ret;
> > }
> > @@ -905,10 +924,13 @@ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
> > {
> > int ret;
> >
> > + ret = dev_pm_qos_constraints_ensure_allocated(dev);
> > + if (ret)
> > + return ret;
> > +
> > mutex_lock(&dev_pm_qos_mtx);
> >
> > - if (IS_ERR_OR_NULL(dev->power.qos)
> > - || !dev->power.qos->latency_tolerance_req) {
> > + if (!dev->power.qos->latency_tolerance_req) {
> > struct dev_pm_qos_request *req;
> >
> > if (val < 0) {
> > --
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: (subset) [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
` (6 preceding siblings ...)
2023-03-20 14:43 ` [PATCH v2 22/23] interconnect: Teach lockdep about icc_bw_lock order Rob Clark
@ 2023-04-07 17:41 ` Bjorn Andersson
7 siblings, 0 replies; 14+ messages in thread
From: Bjorn Andersson @ 2023-04-07 17:41 UTC (permalink / raw)
To: dri-devel, Rob Clark
Cc: Geert Uytterhoeven, Maximilian Luz, Dmitry Baryshkov,
Akhil P Oommen, Konrad Dybcio, Douglas Anderson, Chia-I Wu,
Luca Weiss, Sean Paul, Nathan Chancellor, Rafael J. Wysocki,
open list:DEVICE FREQUENCY DEVFREQ, Rob Clark, Konrad Dybcio,
moderated list:DMA BUFFER SHARING FRAMEWORK, Daniel Vetter,
freedreno, Joel Fernandes (Google),
open list, open list:DMA BUFFER SHARING FRAMEWORK, linux-arm-msm
On Mon, 20 Mar 2023 07:43:22 -0700, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
>
> Inspired by https://lore.kernel.org/dri-devel/20200604081224.863494-10-daniel.vetter@ffwll.ch/
> it seemed like a good idea to get rid of memory allocation in job_run()
> fence signaling path, and use lockdep annotations to yell at us about
> anything that could deadlock against shrinker/reclaim. Anything that
> can trigger reclaim, or block on any other thread that has triggered
> reclaim, can block the GPU shrinker from releasing memory if it is
> waiting the job to complete, causing deadlock.
>
> [...]
Applied, thanks!
[20/23] soc: qcom: smd-rpm: Use GFP_ATOMIC in write path
commit: 5808c532ca0a983d643319caca44f2bcb148298f
Best regards,
--
Bjorn Andersson <andersson@kernel.org>
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2023-04-07 17:39 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-03-20 14:43 [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Rob Clark
2023-03-20 14:43 ` [PATCH v2 15/23] PM / devfreq: Drop unneed locking to appease lockdep Rob Clark
2023-03-20 14:43 ` [PATCH v2 16/23] PM / devfreq: Teach lockdep about locking order Rob Clark
2023-03-20 14:43 ` [PATCH v2 17/23] PM / QoS: Fix constraints alloc vs reclaim locking Rob Clark
2023-03-27 17:53 ` Rafael J. Wysocki
2023-03-27 19:52 ` Rob Clark
2023-03-20 14:43 ` [PATCH v2 18/23] PM / QoS: Decouple request alloc from dev_pm_qos_mtx Rob Clark
2023-03-20 20:13 ` kernel test robot
2023-03-20 20:34 ` kernel test robot
2023-03-21 4:53 ` Dan Carpenter
2023-03-20 14:43 ` [PATCH v2 19/23] PM / QoS: Teach lockdep about dev_pm_qos_mtx locking order Rob Clark
2023-03-20 14:43 ` [PATCH v2 21/23] interconnect: Fix locking for runpm vs reclaim Rob Clark
2023-03-20 14:43 ` [PATCH v2 22/23] interconnect: Teach lockdep about icc_bw_lock order Rob Clark
2023-04-07 17:41 ` (subset) [PATCH v2 00/23] drm/msm+PM+icc: Make job_run() reclaim-safe Bjorn Andersson
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