Security: Potential division by zero in norm_cam_gradients

[barttran2k]

Problem

The norm_cam_gradients kernel divides by *renderer.n_grad_contributions_d using FRCP(static_cast<float>(...)). If no spheres contributed to the gradient (i.e., the value is 0), this results in a division by zero, producing inf or NaN values that can propagate and corrupt downstream computations.

Severity: medium
File: pytorch3d/csrc/pulsar/include/renderer.norm_cam_gradients.device.h

Solution

Add a guard before the division: if (*renderer.n_grad_contributions_d > 0) { *cgi = *cgi * FRCP(static_cast<float>(*renderer.n_grad_contributions_d)); }

Changes

• pytorch3d/csrc/pulsar/include/renderer.norm_cam_gradients.device.h (modified)

Testing

• Existing tests pass
• Manual review completed
• No new warnings/errors introduced

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