On 2019-08-09 17:45:13 [+0200], Yann COLLETTE wrote:
> Hello,
Hi,
> I am using kernel-rt 5.0.21rt16 on fedora 30.
…
> Aug 9 17:16:35 localhost kernel: Preemption disabled at:
> Aug 9 17:16:35 localhost kernel: [<ffffffff8c67239e>]
> reservation_object_add_shared_fence+0x3e/0x1b0
> Aug 9 17:16:35 localhost kernel: CPU: 3 PID: 1087 Comm: Xorg Not tainted
> 5.0.21-rt16.fc30.x86_64 #1
> Aug 9 17:16:35 localhost kernel: Hardware name: HP 450-a121nf/2B29, BIOS
> A0.11 01/15/2016
> Aug 9 17:16:35 localhost kernel: Call Trace:
> Aug 9 17:16:35 localhost kernel: dump_stack+0x5c/0x80
> Aug 9 17:16:35 localhost kernel: ?
> reservation_object_add_shared_fence+0x3e/0x1b0
> Aug 9 17:16:35 localhost kernel: __schedule_bug.cold+0x44/0x51
> Aug 9 17:16:35 localhost kernel: __schedule+0x5c6/0x6f0
> Aug 9 17:16:35 localhost kernel: schedule+0x43/0xd0
> Aug 9 17:16:35 localhost kernel: rt_spin_lock_slowlock_locked+0x114/0x2b0
> Aug 9 17:16:35 localhost kernel: rt_spin_lock_slowlock+0x51/0x80
> Aug 9 17:16:35 localhost kernel: __wake_up_common_lock+0x61/0xb0
> Aug 9 17:16:35 localhost kernel: radeon_fence_is_signaled+0x74/0x90
> [radeon]
> Aug 9 17:16:35 localhost kernel:
> reservation_object_add_shared_fence+0x97/0x1b0
> Aug 9 17:16:35 localhost kernel: radeon_vm_bo_update+0x409/0x640 [radeon]
> Aug 9 17:16:35 localhost kernel: radeon_gem_va_ioctl+0x41c/0x500 [radeon]
…
> I don't know if this bug is related to the kernel of if this is a mesa
> problem.
That backtrace is kernel related. I'm not sure if this is related to the
hang up you observe.
Could you please try the following patch:
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index bf4d4c80fbc67..c6370dcdd77d2 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -168,7 +168,7 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
return 0;
retry:
- seq = read_seqcount_begin(&resv->seq);
+ seq = read_seqbegin(&resv->seq);
rcu_read_lock();
fobj = rcu_dereference(resv->fence);
@@ -177,7 +177,7 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
else
shared_count = 0;
fence_excl = rcu_dereference(resv->fence_excl);
- if (read_seqcount_retry(&resv->seq, seq)) {
+ if (read_seqretry(&resv->seq, seq)) {
rcu_read_unlock();
goto retry;
}
@@ -1034,12 +1034,12 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
robj = buf_obj->resv;
while (true) {
- seq = read_seqcount_begin(&robj->seq);
+ seq = read_seqbegin(&robj->seq);
rcu_read_lock();
fobj = rcu_dereference(robj->fence);
shared_count = fobj ? fobj->shared_count : 0;
fence = rcu_dereference(robj->fence_excl);
- if (!read_seqcount_retry(&robj->seq, seq))
+ if (!read_seqretry(&robj->seq, seq))
break;
rcu_read_unlock();
}
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c
index 4d32e2c678626..37d8f6b18ef90 100644
--- a/drivers/dma-buf/reservation.c
+++ b/drivers/dma-buf/reservation.c
@@ -110,15 +110,13 @@ int reservation_object_reserve_shared(struct reservation_object *obj,
new->shared_count = j;
new->shared_max = max;
- preempt_disable();
- write_seqcount_begin(&obj->seq);
+ write_seqlock(&obj->seq);
/*
* RCU_INIT_POINTER can be used here,
* seqcount provides the necessary barriers
*/
RCU_INIT_POINTER(obj->fence, new);
- write_seqcount_end(&obj->seq);
- preempt_enable();
+ write_sequnlock(&obj->seq);
if (!old)
return 0;
@@ -158,8 +156,7 @@ void reservation_object_add_shared_fence(struct reservation_object *obj,
fobj = reservation_object_get_list(obj);
count = fobj->shared_count;
- preempt_disable();
- write_seqcount_begin(&obj->seq);
+ write_seqlock(&obj->seq);
for (i = 0; i < count; ++i) {
struct dma_fence *old_fence;
@@ -181,8 +178,7 @@ void reservation_object_add_shared_fence(struct reservation_object *obj,
/* pointer update must be visible before we extend the shared_count */
smp_store_mb(fobj->shared_count, count);
- write_seqcount_end(&obj->seq);
- preempt_enable();
+ write_sequnlock(&obj->seq);
}
EXPORT_SYMBOL(reservation_object_add_shared_fence);
@@ -209,14 +205,11 @@ void reservation_object_add_excl_fence(struct reservation_object *obj,
if (fence)
dma_fence_get(fence);
- preempt_disable();
- write_seqcount_begin(&obj->seq);
- /* write_seqcount_begin provides the necessary memory barrier */
+ write_seqlock(&obj->seq);
RCU_INIT_POINTER(obj->fence_excl, fence);
if (old)
old->shared_count = 0;
- write_seqcount_end(&obj->seq);
- preempt_enable();
+ write_sequnlock(&obj->seq);
/* inplace update, no shared fences */
while (i--)
@@ -298,13 +291,10 @@ int reservation_object_copy_fences(struct reservation_object *dst,
src_list = reservation_object_get_list(dst);
old = reservation_object_get_excl(dst);
- preempt_disable();
- write_seqcount_begin(&dst->seq);
- /* write_seqcount_begin provides the necessary memory barrier */
+ write_seqlock(&dst->seq);
RCU_INIT_POINTER(dst->fence_excl, new);
RCU_INIT_POINTER(dst->fence, dst_list);
- write_seqcount_end(&dst->seq);
- preempt_enable();
+ write_sequnlock(&dst->seq);
if (src_list)
kfree_rcu(src_list, rcu);
@@ -345,7 +335,7 @@ int reservation_object_get_fences_rcu(struct reservation_object *obj,
shared_count = i = 0;
rcu_read_lock();
- seq = read_seqcount_begin(&obj->seq);
+ seq = read_seqbegin(&obj->seq);
fence_excl = rcu_dereference(obj->fence_excl);
if (fence_excl && !dma_fence_get_rcu(fence_excl))
@@ -390,7 +380,7 @@ int reservation_object_get_fences_rcu(struct reservation_object *obj,
}
}
- if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) {
+ if (i != shared_count || read_seqretry(&obj->seq, seq)) {
while (i--)
dma_fence_put(shared[i]);
dma_fence_put(fence_excl);
@@ -439,7 +429,7 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
retry:
shared_count = 0;
- seq = read_seqcount_begin(&obj->seq);
+ seq = read_seqbegin(&obj->seq);
rcu_read_lock();
i = -1;
@@ -486,7 +476,7 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
rcu_read_unlock();
if (fence) {
- if (read_seqcount_retry(&obj->seq, seq)) {
+ if (read_seqretry(&obj->seq, seq)) {
dma_fence_put(fence);
goto retry;
}
@@ -542,7 +532,7 @@ bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
retry:
ret = true;
shared_count = 0;
- seq = read_seqcount_begin(&obj->seq);
+ seq = read_seqbegin(&obj->seq);
if (test_all) {
unsigned i;
@@ -563,7 +553,7 @@ bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
break;
}
- if (read_seqcount_retry(&obj->seq, seq))
+ if (read_seqretry(&obj->seq, seq))
goto retry;
}
@@ -576,7 +566,7 @@ bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
if (ret < 0)
goto retry;
- if (read_seqcount_retry(&obj->seq, seq))
+ if (read_seqretry(&obj->seq, seq))
goto retry;
}
}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index a6e5184d436c9..b5fbd16034122 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -250,11 +250,9 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
new->shared_count = k;
/* Install the new fence list, seqcount provides the barriers */
- preempt_disable();
- write_seqcount_begin(&resv->seq);
+ write_seqlock(&resv->seq);
RCU_INIT_POINTER(resv->fence, new);
- write_seqcount_end(&resv->seq);
- preempt_enable();
+ write_sequnlock(&resv->seq);
/* Drop the references to the removed fences or move them to ef_list */
for (i = j, k = 0; i < old->shared_count; ++i) {
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index ad01c92aaf748..2910a133077a3 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -449,7 +449,7 @@ i915_gem_object_wait_reservation(struct reservation_object *resv,
unsigned int flags,
long timeout)
{
- unsigned int seq = __read_seqcount_begin(&resv->seq);
+ unsigned int seq = read_seqbegin(&resv->seq);
struct dma_fence *excl;
bool prune_fences = false;
@@ -500,9 +500,9 @@ i915_gem_object_wait_reservation(struct reservation_object *resv,
* signaled and that the reservation object has not been changed (i.e.
* no new fences have been added).
*/
- if (prune_fences && !__read_seqcount_retry(&resv->seq, seq)) {
+ if (prune_fences && !read_seqretry(&resv->seq, seq)) {
if (reservation_object_trylock(resv)) {
- if (!__read_seqcount_retry(&resv->seq, seq))
+ if (!read_seqretry(&resv->seq, seq))
reservation_object_add_excl_fence(resv, NULL);
reservation_object_unlock(resv);
}
@@ -3943,7 +3943,7 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
*
*/
retry:
- seq = raw_read_seqcount(&obj->resv->seq);
+ seq = read_seqbegin(&obj->resv->seq);
/* Translate the exclusive fence to the READ *and* WRITE engine */
args->busy = busy_check_writer(rcu_dereference(obj->resv->fence_excl));
@@ -3961,7 +3961,7 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
}
}
- if (args->busy && read_seqcount_retry(&obj->resv->seq, seq))
+ if (args->busy && read_seqretry(&obj->resv->seq, seq))
goto retry;
err = 0;
diff --git a/include/linux/reservation.h b/include/linux/reservation.h
index ee750765cc941..11cc05f489365 100644
--- a/include/linux/reservation.h
+++ b/include/linux/reservation.h
@@ -71,7 +71,7 @@ struct reservation_object_list {
*/
struct reservation_object {
struct ww_mutex lock;
- seqcount_t seq;
+ seqlock_t seq;
struct dma_fence __rcu *fence_excl;
struct reservation_object_list __rcu *fence;
@@ -90,7 +90,7 @@ reservation_object_init(struct reservation_object *obj)
{
ww_mutex_init(&obj->lock, &reservation_ww_class);
- __seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
+ seqlock_init(&obj->seq);
RCU_INIT_POINTER(obj->fence, NULL);
RCU_INIT_POINTER(obj->fence_excl, NULL);
}
--
2.23.0.rc1
> Best regards,
>
>
> YC
Sebastian
