drm/msm/gpu: Push gpu lock down past runpm

robclark · robclark · commit abe2023b4cea · 2023-08-15T10:09:30.000-07:00
Avoid holding gpu lock when calling runpm, to avoid this lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 6.4.3-debug+ #14 Not tainted ------------------------------------------------------ ring0/373 is trying to acquire lock: ffffffead86efb98 (prepare_lock){+.+.}-{3:3}, at: clk_prepare_lock+0x70/0x98 but task is already holding lock: ffffff809cd19170 (&gpu->lock){+.+.}-{3:3}, at: msm_job_run+0x7c/0x128 [msm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&gpu->lock){+.+.}-{3:3}: __mutex_lock+0xc8/0x388 mutex_lock_nested+0x2c/0x38 msm_job_run+0x7c/0x128 [msm] drm_sched_main+0x264/0x354 [gpu_sched] kthread+0xf0/0x100 ret_from_fork+0x10/0x20 -> #3 (dma_fence_map){++++}-{0:0}: __dma_fence_might_wait+0x74/0xc0 dma_resv_lockdep+0x1f0/0x2e8 do_one_initcall+0xb4/0x214 kernel_init_freeable+0x338/0x33c kernel_init+0x30/0x134 ret_from_fork+0x10/0x20 -> #2 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}: fs_reclaim_acquire+0x7c/0x9c slab_pre_alloc_hook.constprop.0+0x40/0x250 __kmem_cache_alloc_node+0x60/0x18c kmalloc_node_trace+0x40/0x84 alloc_worker+0x2c/0x64 init_rescuer+0x34/0xe0 workqueue_init+0x168/0x1fc kernel_init_freeable+0x15c/0x33c kernel_init+0x30/0x134 ret_from_fork+0x10/0x20 -> #1 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire+0x3c/0x48 fs_reclaim_acquire+0x50/0x9c slab_pre_alloc_hook.constprop.0+0x40/0x250 __kmem_cache_alloc_node+0x60/0x18c kmalloc_trace+0x44/0x88 clk_rcg2_dfs_determine_rate+0x60/0x214 clk_core_determine_round_nolock+0xb8/0xf0 clk_core_round_rate_nolock+0x84/0x118 clk_core_round_rate_nolock+0xd8/0x118 clk_round_rate+0x6c/0xd0 geni_se_clk_tbl_get+0x78/0xc0 geni_se_clk_freq_match+0x44/0xe4 get_spi_clk_cfg+0x50/0xf4 geni_spi_set_clock_and_bw+0x54/0x104 spi_geni_prepare_message+0x130/0x174 __spi_pump_transfer_message+0x200/0x4d8 __spi_sync+0x13c/0x23c spi_sync_locked+0x18/0x24 do_cros_ec_pkt_xfer_spi+0x124/0x3f0 cros_ec_xfer_high_pri_work+0x28/0x3c kthread_worker_fn+0x14c/0x27c kthread+0xf0/0x100 ret_from_fork+0x10/0x20 -> #0 (prepare_lock){+.+.}-{3:3}: __lock_acquire+0xdf8/0x109c lock_acquire+0x234/0x284 __mutex_lock+0xc8/0x388 mutex_lock_nested+0x2c/0x38 clk_prepare_lock+0x70/0x98 clk_prepare+0x24/0x50 clk_bulk_prepare+0x50/0x9c a6xx_gmu_resume+0x94/0x800 [msm] a6xx_gmu_pm_resume+0x38/0x158 [msm] adreno_runtime_resume+0x2c/0x38 [msm] pm_generic_runtime_resume+0x30/0x44 __rpm_callback+0x4c/0x134 rpm_callback+0x78/0x7c rpm_resume+0x3a4/0x46c __pm_runtime_resume+0x78/0xbc pm_runtime_get_sync.isra.0+0x14/0x20 [msm] msm_gpu_submit+0x4c/0x12c [msm] msm_job_run+0x88/0x128 [msm] drm_sched_main+0x264/0x354 [gpu_sched] kthread+0xf0/0x100 ret_from_fork+0x10/0x20 other info that might help us debug this: Chain exists of: prepare_lock --> dma_fence_map --> &gpu->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&gpu->lock); lock(dma_fence_map); lock(&gpu->lock); lock(prepare_lock); *** DEADLOCK *** 2 locks held by ring0/373: #0: ffffffead875ae50 (dma_fence_map){++++}-{0:0}, at: drm_sched_main+0x54/0x354 [gpu_sched] #1: ffffff809cd19170 (&gpu->lock){+.+.}-{3:3}, at: msm_job_run+0x7c/0x128 [msm] stack backtrace: CPU: 2 PID: 373 Comm: ring0 Not tainted 6.4.3-debug+ #14 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 clk_prepare_lock+0x70/0x98 clk_prepare+0x24/0x50 clk_bulk_prepare+0x50/0x9c a6xx_gmu_resume+0x94/0x800 [msm] a6xx_gmu_pm_resume+0x38/0x158 [msm] adreno_runtime_resume+0x2c/0x38 [msm] pm_generic_runtime_resume+0x30/0x44 __rpm_callback+0x4c/0x134 rpm_callback+0x78/0x7c rpm_resume+0x3a4/0x46c __pm_runtime_resume+0x78/0xbc pm_runtime_get_sync.isra.0+0x14/0x20 [msm] msm_gpu_submit+0x4c/0x12c [msm] msm_job_run+0x88/0x128 [msm] drm_sched_main+0x264/0x354 [gpu_sched] kthread+0xf0/0x100 ret_from_fork+0x10/0x20 Signed-off-by: Rob Clark <robdclark@chromium.org> Patchwork: https://patchwork.freedesktop.org/patch/552298/
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
@@ -749,13 +749,11 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 	struct msm_ringbuffer *ring = submit->ring;
 	unsigned long flags;
 
-	WARN_ON(!mutex_is_locked(&gpu->lock));
-
 	pm_runtime_get_sync(&gpu->pdev->dev);
 
-	msm_gpu_hw_init(gpu);
+	mutex_lock(&gpu->lock);
 
-	submit->seqno = submit->hw_fence->seqno;
+	msm_gpu_hw_init(gpu);
 
 	update_sw_cntrs(gpu);
 
@@ -781,8 +779,11 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 	gpu->funcs->submit(gpu, submit);
 	gpu->cur_ctx_seqno = submit->queue->ctx->seqno;
 
-	pm_runtime_put(&gpu->pdev->dev);
 	hangcheck_timer_reset(gpu);
+
+	mutex_unlock(&gpu->lock);
+
+	pm_runtime_put(&gpu->pdev->dev);
 }
 
 /*
diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.c b/drivers/gpu/drm/msm/msm_ringbuffer.c
@@ -21,6 +21,8 @@ static struct dma_fence *msm_job_run(struct drm_sched_job *job)
 
 	msm_fence_init(submit->hw_fence, fctx);
 
+	submit->seqno = submit->hw_fence->seqno;
+
 	mutex_lock(&priv->lru.lock);
 
 	for (i = 0; i < submit->nr_bos; i++) {
@@ -32,13 +34,8 @@ static struct dma_fence *msm_job_run(struct drm_sched_job *job)
 
 	mutex_unlock(&priv->lru.lock);
 
-	/* TODO move submit path over to using a per-ring lock.. */
-	mutex_lock(&gpu->lock);
-
 	msm_gpu_submit(gpu, submit);
 
-	mutex_unlock(&gpu->lock);
-
 	return dma_fence_get(submit->hw_fence);
 }
 
