6.12-stable review patch. If anyone has any objections, please let me know.
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From: Philip Yang Philip.Yang@amd.com
[ Upstream commit 7574f30337e19045f03126b4c51f525b84e5049e ]
If mmap write lock is taken while draining retry fault, mmap write lock is not released because svm_range_restore_pages calls mmap_read_unlock then returns. This causes deadlock and system hangs later because mmap read or write lock cannot be taken.
Downgrade mmap write lock to read lock if draining retry fault fix this bug.
Signed-off-by: Philip Yang Philip.Yang@amd.com Reviewed-by: Harish Kasiviswanathan Harish.Kasiviswanathan@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 | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 155948dc3d07a..0d950a20741d8 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -3036,6 +3036,8 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid, if (svms->checkpoint_ts[gpuidx] != 0) { if (amdgpu_ih_ts_after_or_equal(ts, svms->checkpoint_ts[gpuidx])) { pr_debug("draining retry fault, drop fault 0x%llx\n", addr); + if (write_locked) + mmap_write_downgrade(mm); r = -EAGAIN; goto out_unlock_svms; } else {