The job embedded fence donesn't initialize the flags at dma_fence_init(). Then we will go a wrong way in amdgpu_fence_get_timeline_name callback and trigger a null pointer panic once we enabled the trace event here. So introduce new amdgpu_fence object to indicate the job embedded fence.

[ 156.131790] BUG: kernel NULL pointer dereference, address: 00000000000002a0 [ 156.131804] #PF: supervisor read access in kernel mode [ 156.131811] #PF: error_code(0x0000) - not-present page [ 156.131817] PGD 0 P4D 0 [ 156.131824] Oops: 0000 [#1] PREEMPT SMP PTI [ 156.131832] CPU: 6 PID: 1404 Comm: sdma0 Tainted: G OE 5.16.0-rc1-custom #1 [ 156.131842] Hardware name: Gigabyte Technology Co., Ltd. Z170XP-SLI/Z170XP-SLI-CF, BIOS F20 11/04/2016 [ 156.131848] RIP: 0010:strlen+0x0/0x20 [ 156.131859] Code: 89 c0 c3 0f 1f 80 00 00 00 00 48 01 fe eb 0f 0f b6 07 38 d0 74 10 48 83 c7 01 84 c0 74 05 48 39 f7 75 ec 31 c0 c3 48 89 f8 c3 <80> 3f 00 74 10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3 31 [ 156.131872] RSP: 0018:ffff9bd0018dbcf8 EFLAGS: 00010206 [ 156.131880] RAX: 00000000000002a0 RBX: ffff8d0305ef01b0 RCX: 000000000000000b [ 156.131888] RDX: ffff8d03772ab924 RSI: ffff8d0305ef01b0 RDI: 00000000000002a0 [ 156.131895] RBP: ffff9bd0018dbd60 R08: ffff8d03002094d0 R09: 0000000000000000 [ 156.131901] R10: 000000000000005e R11: 0000000000000065 R12: ffff8d03002094d0 [ 156.131907] R13: 000000000000001f R14: 0000000000070018 R15: 0000000000000007 [ 156.131914] FS: 0000000000000000(0000) GS:ffff8d062ed80000(0000) knlGS:0000000000000000 [ 156.131923] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 156.131929] CR2: 00000000000002a0 CR3: 000000001120a005 CR4: 00000000003706e0 [ 156.131937] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 156.131942] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 156.131949] Call Trace: [ 156.131953] <TASK> [ 156.131957] ? trace_event_raw_event_dma_fence+0xcc/0x200 [ 156.131973] ? ring_buffer_unlock_commit+0x23/0x130 [ 156.131982] dma_fence_init+0x92/0xb0 [ 156.131993] amdgpu_fence_emit+0x10d/0x2b0 [amdgpu] [ 156.132302] amdgpu_ib_schedule+0x2f9/0x580 [amdgpu] [ 156.132586] amdgpu_job_run+0xed/0x220 [amdgpu]

Signed-off-by: Huang Rui ray.huang@amd.com ---

V1 -> V2: add another amdgpu_fence_ops which is for job-embedded fence. V2 -> V3: use amdgpu_fence_driver_clear_job_fences abstract the job fence clearing operation.

--- drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 11 +- drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 126 ++++++++++++++------- drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 4 +- 3 files changed, 90 insertions(+), 51 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c index 5625f7736e37..fecf7a09e5a2 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -4456,7 +4456,7 @@ int amdgpu_device_mode1_reset(struct amdgpu_device *adev) int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev, struct amdgpu_reset_context *reset_context) { - int i, j, r = 0; + int i, r = 0; struct amdgpu_job *job = NULL; bool need_full_reset = test_bit(AMDGPU_NEED_FULL_RESET, &reset_context->flags); @@ -4478,15 +4478,8 @@ int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,

/*clear job fence from fence drv to avoid force_completion *leave NULL and vm flush fence in fence drv */ - for (j = 0; j <= ring->fence_drv.num_fences_mask; j++) { - struct dma_fence *old, **ptr; + amdgpu_fence_driver_clear_job_fences(ring);

- ptr = &ring->fence_drv.fences[j]; - old = rcu_dereference_protected(*ptr, 1); - if (old && test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &old->flags)) { - RCU_INIT_POINTER(*ptr, NULL); - } - } /* after all hw jobs are reset, hw fence is meaningless, so force_completion */ amdgpu_fence_driver_force_completion(ring); } diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c index 3b7e86ea7167..db41d16838b9 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c @@ -77,11 +77,13 @@ void amdgpu_fence_slab_fini(void) * Cast helper */ static const struct dma_fence_ops amdgpu_fence_ops; +static const struct dma_fence_ops amdgpu_job_fence_ops; static inline struct amdgpu_fence *to_amdgpu_fence(struct dma_fence *f) { struct amdgpu_fence *__f = container_of(f, struct amdgpu_fence, base);

- if (__f->base.ops == &amdgpu_fence_ops) + if (__f->base.ops == &amdgpu_fence_ops || + __f->base.ops == &amdgpu_job_fence_ops) return __f;

return NULL; @@ -158,19 +160,18 @@ int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f, struct amd }

seq = ++ring->fence_drv.sync_seq; - if (job != NULL && job->job_run_counter) { + if (job && job->job_run_counter) { /* reinit seq for resubmitted jobs */ fence->seqno = seq; } else { - dma_fence_init(fence, &amdgpu_fence_ops, - &ring->fence_drv.lock, - adev->fence_context + ring->idx, - seq); - } - - if (job != NULL) { - /* mark this fence has a parent job */ - set_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &fence->flags); + if (job) + dma_fence_init(fence, &amdgpu_job_fence_ops, + &ring->fence_drv.lock, + adev->fence_context + ring->idx, seq); + else + dma_fence_init(fence, &amdgpu_fence_ops, + &ring->fence_drv.lock, + adev->fence_context + ring->idx, seq); }

amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr, @@ -620,6 +621,25 @@ void amdgpu_fence_driver_hw_init(struct amdgpu_device *adev) } }

+/** + * amdgpu_fence_clear_job_fences - clear job embedded fences of ring + * + * @ring: fence of the ring to be cleared + * + */ +void amdgpu_fence_driver_clear_job_fences(struct amdgpu_ring *ring) +{ + int i; + struct dma_fence *old, **ptr; + + for (i = 0; i <= ring->fence_drv.num_fences_mask; i++) { + ptr = &ring->fence_drv.fences[i]; + old = rcu_dereference_protected(*ptr, 1); + if (old && old->ops == &amdgpu_job_fence_ops) + RCU_INIT_POINTER(*ptr, NULL); + } +} + /** * amdgpu_fence_driver_force_completion - force signal latest fence of ring * @@ -643,16 +663,14 @@ static const char *amdgpu_fence_get_driver_name(struct dma_fence *fence)

static const char *amdgpu_fence_get_timeline_name(struct dma_fence *f) { - struct amdgpu_ring *ring; + return (const char *)to_amdgpu_fence(f)->ring->name; +}

- if (test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &f->flags)) { - struct amdgpu_job *job = container_of(f, struct amdgpu_job, hw_fence); +static const char *amdgpu_job_fence_get_timeline_name(struct dma_fence *f) +{ + struct amdgpu_job *job = container_of(f, struct amdgpu_job, hw_fence);

- ring = to_amdgpu_ring(job->base.sched); - } else { - ring = to_amdgpu_fence(f)->ring; - } - return (const char *)ring->name; + return (const char *)to_amdgpu_ring(job->base.sched)->name; }

/** @@ -665,18 +683,25 @@ static const char *amdgpu_fence_get_timeline_name(struct dma_fence *f) */ static bool amdgpu_fence_enable_signaling(struct dma_fence *f) { - struct amdgpu_ring *ring; + if (!timer_pending(&to_amdgpu_fence(f)->ring->fence_drv.fallback_timer)) + amdgpu_fence_schedule_fallback(to_amdgpu_fence(f)->ring);

- if (test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &f->flags)) { - struct amdgpu_job *job = container_of(f, struct amdgpu_job, hw_fence); + return true; +}

- ring = to_amdgpu_ring(job->base.sched); - } else { - ring = to_amdgpu_fence(f)->ring; - } +/** + * amdgpu_job_fence_enable_signaling - enable signalling on job fence + * @f: fence + * + * This is the simliar function with amdgpu_fence_enable_signaling above, it + * only handles the job embedded fence. + */ +static bool amdgpu_job_fence_enable_signaling(struct dma_fence *f) +{ + struct amdgpu_job *job = container_of(f, struct amdgpu_job, hw_fence);

- if (!timer_pending(&ring->fence_drv.fallback_timer)) - amdgpu_fence_schedule_fallback(ring); + if (!timer_pending(&to_amdgpu_ring(job->base.sched)->fence_drv.fallback_timer)) + amdgpu_fence_schedule_fallback(to_amdgpu_ring(job->base.sched));

return true; } @@ -692,19 +717,23 @@ static void amdgpu_fence_free(struct rcu_head *rcu) { struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);

- if (test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &f->flags)) { - /* free job if fence has a parent job */ - struct amdgpu_job *job; - - job = container_of(f, struct amdgpu_job, hw_fence); - kfree(job); - } else { /* free fence_slab if it's separated fence*/ - struct amdgpu_fence *fence; + kmem_cache_free(amdgpu_fence_slab, to_amdgpu_fence(f)); +}

- fence = to_amdgpu_fence(f); - kmem_cache_free(amdgpu_fence_slab, fence); - } +/** + * amdgpu_job_fence_free - free up the job with embedded fence + * + * @rcu: RCU callback head + * + * Free up the job with embedded fence after the RCU grace period. + */ +static void amdgpu_job_fence_free(struct rcu_head *rcu) +{ + struct dma_fence *f = container_of(rcu, struct dma_fence, rcu); + + /* free job if fence has a parent job */ + kfree(container_of(f, struct amdgpu_job, hw_fence)); }

/** @@ -720,6 +749,19 @@ static void amdgpu_fence_release(struct dma_fence *f) call_rcu(&f->rcu, amdgpu_fence_free); }

+/** + * amdgpu_job_fence_release - callback that job embedded fence can be freed + * + * @f: fence + * + * This is the simliar function with amdgpu_fence_release above, it + * only handles the job embedded fence. + */ +static void amdgpu_job_fence_release(struct dma_fence *f) +{ + call_rcu(&f->rcu, amdgpu_job_fence_free); +} + static const struct dma_fence_ops amdgpu_fence_ops = { .get_driver_name = amdgpu_fence_get_driver_name, .get_timeline_name = amdgpu_fence_get_timeline_name, @@ -727,6 +769,12 @@ static const struct dma_fence_ops amdgpu_fence_ops = { .release = amdgpu_fence_release, };

+static const struct dma_fence_ops amdgpu_job_fence_ops = { + .get_driver_name = amdgpu_fence_get_driver_name, + .get_timeline_name = amdgpu_job_fence_get_timeline_name, + .enable_signaling = amdgpu_job_fence_enable_signaling, + .release = amdgpu_job_fence_release, +};

/* * Fence debugfs diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h index 4d380e79752c..fae7d185ad0d 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h @@ -53,9 +53,6 @@ enum amdgpu_ring_priority_level { #define AMDGPU_FENCE_FLAG_INT (1 << 1) #define AMDGPU_FENCE_FLAG_TC_WB_ONLY (1 << 2)

-/* fence flag bit to indicate the face is embedded in job*/ -#define AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT (DMA_FENCE_FLAG_USER_BITS + 1) - #define to_amdgpu_ring(s) container_of((s), struct amdgpu_ring, sched)

#define AMDGPU_IB_POOL_SIZE (1024 * 1024) @@ -114,6 +111,7 @@ struct amdgpu_fence_driver { struct dma_fence **fences; };

+void amdgpu_fence_driver_clear_job_fences(struct amdgpu_ring *ring); void amdgpu_fence_driver_force_completion(struct amdgpu_ring *ring);

int amdgpu_fence_driver_init_ring(struct amdgpu_ring *ring,