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fix(emboss): raise worker thread stack to 256MB to survive CGAL exact-arithmetic text-cut (macOS SIGBUS) #559

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fix(emboss): raise worker thread stack to 256MB to survive CGAL exact-arithmetic text-cut (macOS SIGBUS) #559

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ffd29e5
fix(emboss): raise worker thread stack to 256MB to survive CGAL exact…
Jcapehart2 Jun 30, 2026
b05204c
fix(emboss): bump CGAL 5.4 -> 5.6.3 to fix corefine exact-arithmetic …
Jcapehart2 Jul 1, 2026
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13 changes: 8 additions & 5 deletions deps/CGAL/CGAL.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -5,11 +5,14 @@ endif ()
Snapmaker_Orca_add_cmake_project(
CGAL
# GIT_REPOSITORY https://github.com/CGAL/cgal.git
# GIT_TAG bec70a6d52d8aacb0b3d82a7b4edc3caa899184b # releases/CGAL-5.0
# For whatever reason, this keeps downloading forever (repeats downloads if finished)
URL https://github.com/CGAL/cgal/archive/refs/tags/v5.4.zip
URL_HASH SHA256=d7605e0a5a5ca17da7547592f6f6e4a59430a0bc861948974254d0de43eab4c0
PATCH_COMMAND git apply ${CGAL_DIRECTORY_FLAG} --verbose --ignore-space-change --whitespace=fix ${CMAKE_CURRENT_LIST_DIR}/0001-clang19.patch
# GIT_TAG 3654f780ae0c64675cabaef0e5ddaf904c48b4b7 # releases/CGAL-5.6.3
# Bumped CGAL 5.4 -> 5.6.3 (matching mainline OrcaSlicer) to fix the Emboss
# "On Surface" cut_surface crash: a heap over-read inside CGAL's corefinement
# exact-arithmetic (Epeck) constrained triangulation on macOS/arm64. 5.6.3 is
# API-compatible with this Emboss/CutSurface code (mainline ships it). The
# 5.4-only 0001-clang19.patch is dropped (does not apply to 5.6.3).
URL https://github.com/CGAL/cgal/releases/download/v5.6.3/CGAL-5.6.3.zip
URL_HASH SHA256=5d577acb4a9918ccb960491482da7a3838f8d363aff47e14d703f19fd84733d4
DEPENDS dep_Boost dep_GMP dep_MPFR
)

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7 changes: 6 additions & 1 deletion src/libslic3r/Thread.hpp
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Expand Up @@ -50,7 +50,12 @@ inline boost::thread create_thread(boost::thread::attributes &attrs, Fn &&fn)
// threads of the thread pool: allocate 4MB on a 64bit system, allocate 2MB
// on a 32bit system by default.

attrs.set_stack_size((sizeof(void*) == 4) ? (2048 * 1024) : (4096 * 1024));
// Orca: the Emboss "On Surface" text-cut calls CGAL Polygon_mesh_processing::corefine,
// which falls back to exact rational (GMP/mpq) arithmetic on near-degenerate inputs and
// recurses deeply. The old 4 MB stack (and even the 16 MB upstream bump) overflows into the
// stack guard page -> EXC_BAD_ACCESS/SIGBUS in __gmpn_*/__gmpz_gcd on macOS. Reserve 256 MB;
// macOS/Linux commit thread-stack pages lazily, so idle workers cost address space, not RAM.
attrs.set_stack_size(256ull * 1024 * 1024);
return boost::thread{attrs, std::forward<Fn>(fn)};
}

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