On 2021-12-14 6:15 a.m., Huang Rui wrote:
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: 000000amdgpu_job_alloc00000002a0 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@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 3 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 117 ++++++++++++++-------
drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 3 -
4 files changed, 80 insertions(+), 44 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 9f017663ac50..fcaf6e9703f9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -444,6 +444,7 @@ struct amdgpu_sa_bo {
int amdgpu_fence_slab_init(void);
void amdgpu_fence_slab_fini(void);
+bool is_job_embedded_fence(struct dma_fence *f);
/*
* IRQS.
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 5625f7736e37..444a19eb2248 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4483,9 +4483,8 @@ int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
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)) {
+ if (old && is_job_embedded_fence(old))
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..3a81249b5660 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -77,16 +77,28 @@ 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;
}
+bool is_job_embedded_fence(struct dma_fence *f)
+{
+ struct amdgpu_fence *__f = container_of(f, struct amdgpu_fence, base);
+
+ if (__f->base.ops == &amdgpu_job_fence_ops)
+ return true;
+
+ return false;
+}
+
/**
* amdgpu_fence_write - write a fence value
*
@@ -158,19 +170,18 @@ 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);
}
It's probably me missing something but why can't we just move setting of
AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT
to before dma_fence_init here or even into amdgpu_job_alloc instead of
all the refactoring ?
Andrey
amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
@@ -643,16 +654,14 @@ 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 +674,25 @@ 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 +708,23 @@ 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 +740,19 @@ 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 +760,12 @@ 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..c29554cf6e63 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)
