drm/amdgpu: fix system hang issue during GPU reset

when GPU hang, driver has multi-paths to enter amdgpu_device_gpu_recover,
the atomic adev->in_gpu_reset and hive->in_reset are used to avoid
re-entering GPU recovery.

During GPU reset and resume, it is unsafe that other threads access GPU,
which maybe cause GPU reset failed. Therefore the new rw_semaphore
adev->reset_sem is introduced, which protect GPU from being accessed by
external threads during recovery.

v2:
1. add rwlock for some ioctls, debugfs and file-close function.
2. change to use dqm->is_resetting and dqm_lock for protection in kfd
driver.
3. remove try_lock and change adev->in_gpu_reset as atomic, to avoid
re-enter GPU recovery for the same GPU hang.

v3:
1. change back to use adev->reset_sem to protect kfd callback
functions, because dqm_lock couldn't protect all codes, for example:
free_mqd must be called outside of dqm_lock;

[ 1230.176199] Hardware name: Supermicro SYS-7049GP-TRT/X11DPG-QT, BIOS 3.1 05/23/2019
[ 1230.177221] Call Trace:
[ 1230.178249]  dump_stack+0x98/0xd5
[ 1230.179443]  amdgpu_virt_kiq_reg_write_reg_wait+0x181/0x190 [amdgpu]
[ 1230.180673]  gmc_v9_0_flush_gpu_tlb+0xcc/0x310 [amdgpu]
[ 1230.181882]  amdgpu_gart_unbind+0xa9/0xe0 [amdgpu]
[ 1230.183098]  amdgpu_ttm_backend_unbind+0x46/0x180 [amdgpu]
[ 1230.184239]  ? ttm_bo_put+0x171/0x5f0 [ttm]
[ 1230.185394]  ttm_tt_unbind+0x21/0x40 [ttm]
[ 1230.186558]  ttm_tt_destroy.part.12+0x12/0x60 [ttm]
[ 1230.187707]  ttm_tt_destroy+0x13/0x20 [ttm]
[ 1230.188832]  ttm_bo_cleanup_memtype_use+0x36/0x80 [ttm]
[ 1230.189979]  ttm_bo_put+0x1be/0x5f0 [ttm]
[ 1230.191230]  amdgpu_bo_unref+0x1e/0x30 [amdgpu]
[ 1230.192522]  amdgpu_amdkfd_free_gtt_mem+0xaf/0x140 [amdgpu]
[ 1230.193833]  free_mqd+0x25/0x40 [amdgpu]
[ 1230.195143]  destroy_queue_cpsch+0x1a7/0x270 [amdgpu]
[ 1230.196475]  pqm_destroy_queue+0x105/0x260 [amdgpu]
[ 1230.197819]  kfd_ioctl_destroy_queue+0x37/0x70 [amdgpu]
[ 1230.199154]  kfd_ioctl+0x277/0x500 [amdgpu]
[ 1230.200458]  ? kfd_ioctl_get_clock_counters+0x60/0x60 [amdgpu]
[ 1230.201656]  ? tomoyo_file_ioctl+0x19/0x20
[ 1230.202831]  ksys_ioctl+0x98/0xb0
[ 1230.204004]  __x64_sys_ioctl+0x1a/0x20
[ 1230.205174]  do_syscall_64+0x5f/0x250
[ 1230.206339]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

2. remove try_lock and introduce atomic hive->in_reset, to avoid
re-enter GPU recovery.

v4:
1. remove an unnecessary whitespace change in kfd_chardev.c
2. remove comment codes in amdgpu_device.c
3. add more detailed comment in commit message
4. define a wrap function amdgpu_in_reset

v5:
1. Fix some style issues.

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Suggested-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Suggested-by: Felix Kuehling <Felix.Kuehling@amd.com>
Suggested-by: Lijo Lazar <Lijo.Lazar@amd.com>
Suggested-by: Luben Tukov <luben.tuikov@amd.com>
Signed-off-by: Dennis Li <Dennis.Li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
index 193ffdb957b6..3a4b31b1c4f2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -100,14 +100,14 @@ static int amdgpu_debugfs_autodump_open(struct inode *inode, struct file *file)
 
 	file->private_data = adev;
 
-	mutex_lock(&adev->lock_reset);
+	down_read(&adev->reset_sem);
 	if (adev->autodump.dumping.done) {
 		reinit_completion(&adev->autodump.dumping);
 		ret = 0;
 	} else {
 		ret = -EBUSY;
 	}
-	mutex_unlock(&adev->lock_reset);
+	up_read(&adev->reset_sem);
 
 	return ret;
 }
@@ -126,7 +126,7 @@ static unsigned int amdgpu_debugfs_autodump_poll(struct file *file, struct poll_
 
 	poll_wait(file, &adev->autodump.gpu_hang, poll_table);
 
-	if (adev->in_gpu_reset)
+	if (amdgpu_in_reset(adev))
 		return POLLIN | POLLRDNORM | POLLWRNORM;
 
 	return 0;
@@ -1241,7 +1241,7 @@ static int amdgpu_debugfs_test_ib(struct seq_file *m, void *data)
 	}
 
 	/* Avoid accidently unparking the sched thread during GPU reset */
-	mutex_lock(&adev->lock_reset);
+	down_read(&adev->reset_sem);
 
 	/* hold on the scheduler */
 	for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
@@ -1268,7 +1268,7 @@ static int amdgpu_debugfs_test_ib(struct seq_file *m, void *data)
 		kthread_unpark(ring->sched.thread);
 	}
 
-	mutex_unlock(&adev->lock_reset);
+	up_read(&adev->reset_sem);
 
 	pm_runtime_mark_last_busy(dev->dev);
 	pm_runtime_put_autosuspend(dev->dev);
@@ -1458,7 +1458,7 @@ static int amdgpu_debugfs_ib_preempt(void *data, u64 val)
 		return -ENOMEM;
 
 	/* Avoid accidently unparking the sched thread during GPU reset */
-	mutex_lock(&adev->lock_reset);
+	down_read(&adev->reset_sem);
 
 	/* stop the scheduler */
 	kthread_park(ring->sched.thread);
@@ -1499,7 +1499,7 @@ failure:
 	/* restart the scheduler */
 	kthread_unpark(ring->sched.thread);
 
-	mutex_unlock(&adev->lock_reset);
+	up_read(&adev->reset_sem);
 
 	ttm_bo_unlock_delayed_workqueue(&adev->mman.bdev, resched);