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Fix #148071: EEVEE: Crash when using Sky Texture + Multi-scattering

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Caused by some tricky use after-free / stack corruption.
This affect both Cycles and EEVEE.

The `sms` local variable is getting dereferenced by `get_inscattering`
inside the threaded for loop but is passed by copy to the lambda expression.
This makes its lifetime ill-defined in a multithreaded context.
I am not fully sure about the rules at play here so maybe my understanding
is wrong. But removing the call to `get_inscattering` avoids the crash.

Note that `SkyMultipleScattering` is also very big (it contains the whole LUT).
So copying it might have caused stack overflow. But that should trigger a
system interupt.

Passing everything by references fixes the issue.
This seems to be safe since all as the other local variables are `const` anyway.
Also the loop doesn't seem to modify the one that aren't.

Pull Request: https://projects.blender.org/blender/blender/pulls/148260
This commit is contained in:
Clément Foucault
2025-10-17 14:39:31 +02:00
committed by Clément Foucault
parent 861a174a82
commit 632bd741f7
1 changed files with 1 additions and 1 deletions
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2
intern/sky/source/sky_multiple_scattering.cpp
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@@ -319,7 +319,7 @@ void SKY_multiple_scattering_precompute_texture(float *pixels,
const float3 sun_dir = sun_direction(sun_zenith_cos_angle); const float3 sun_dir = sun_direction(sun_zenith_cos_angle);
const int rows_per_task = std::max(1024 / width, 1); const int rows_per_task = std::max(1024 / width, 1);
SKY_parallel_for(0, height, rows_per_task, [=](const size_t begin, const size_t end) { SKY_parallel_for(0, height, rows_per_task, [&](const size_t begin, const size_t end) {
for (int y = begin; y < end; y++) { for (int y = begin; y < end; y++) {
float *pixel_row = pixels + (y * width * stride); float *pixel_row = pixels + (y * width * stride);
for (int x = 0; x < half_width; x++) { for (int x = 0; x < half_width; x++) {