From: Emily Deng Emily.Deng@amd.com
[ Upstream commit f844732e3ad9c4b78df7436232949b8d2096d1a6 ]
Issue: In the scenario where svm_range_restore_pages is called, but svm->checkpoint_ts has not been set and the retry fault has not been drained, svm_range_unmap_from_cpu is triggered and calls svm_range_free. Meanwhile, svm_range_restore_pages continues execution and reaches svm_range_from_addr. This results in a "failed to find prange..." error, causing the page recovery to fail.
How to fix: Move the timestamp check code under the protection of svm->lock.
v2: Make sure all right locks are released before go out.
v3: Directly goto out_unlock_svms, and return -EAGAIN.
v4: Refine code.
Signed-off-by: Emily Deng Emily.Deng@amd.com Reviewed-by: Felix Kuehling felix.kuehling@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 31 +++++++++++++++------------- 1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 1b04d54f9a69c..4eeea51c9a0eb 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -2992,19 +2992,6 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid, goto out; }
- /* check if this page fault time stamp is before svms->checkpoint_ts */ - if (svms->checkpoint_ts[gpuidx] != 0) { - if (amdgpu_ih_ts_after(ts, svms->checkpoint_ts[gpuidx])) { - pr_debug("draining retry fault, drop fault 0x%llx\n", addr); - r = 0; - goto out; - } else - /* ts is after svms->checkpoint_ts now, reset svms->checkpoint_ts - * to zero to avoid following ts wrap around give wrong comparing - */ - svms->checkpoint_ts[gpuidx] = 0; - } - if (!p->xnack_enabled) { pr_debug("XNACK not enabled for pasid 0x%x\n", pasid); r = -EFAULT; @@ -3024,6 +3011,21 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid, mmap_read_lock(mm); retry_write_locked: mutex_lock(&svms->lock); + + /* check if this page fault time stamp is before svms->checkpoint_ts */ + if (svms->checkpoint_ts[gpuidx] != 0) { + if (amdgpu_ih_ts_after(ts, svms->checkpoint_ts[gpuidx])) { + pr_debug("draining retry fault, drop fault 0x%llx\n", addr); + r = -EAGAIN; + goto out_unlock_svms; + } else { + /* ts is after svms->checkpoint_ts now, reset svms->checkpoint_ts + * to zero to avoid following ts wrap around give wrong comparing + */ + svms->checkpoint_ts[gpuidx] = 0; + } + } + prange = svm_range_from_addr(svms, addr, NULL); if (!prange) { pr_debug("failed to find prange svms 0x%p address [0x%llx]\n", @@ -3149,7 +3151,8 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid, mutex_unlock(&svms->lock); mmap_read_unlock(mm);
- svm_range_count_fault(node, p, gpuidx); + if (r != -EAGAIN) + svm_range_count_fault(node, p, gpuidx);
mmput(mm); out: