Memory error in the in/out query

[agcapps]

User reports an Umpire error message saying "Cannot find allocator for pointer: ." Here is an excerpt of the stack trace, deepest at top:

~axom::Array
~axom::Polygon
axom::primal::clip
quest::inOutOctree<3>::withinGrayBlock

The crash is in clip.hpp, line 100, when it goes out of scope. I think from the stack allocated poly[2] array (line 54). The poly array entries are passed back to the caller and copied into separate variables. I'm not sure if the m_vertices are being copied correctly. In particular, does the destructor called when clip() goes out-of-scope occur before or after the assignment of the new polygon.

This is a very large problem. The user's code is using the in/out query to process STL files; the error occurs on the second file. That file may not be available for us to troubleshoot.

[kennyweiss]

Thanks for reporting this @agcapps.

That's not a lot to go on...

• Presumably, this is a configuration w/ Umpire
• What's the platform? (e.g. toss3, toss4, blueos, windows, ...?)
• Also, which compiler are you using? Is there a device compiler as well?
• It's worth noting that the In/Out has not yet been ported to GPUs, so, hopefully all the allocators you're dealing with are HOST-based (?)

Any chance, the following change helps?

diff --git a/src/axom/primal/operators/clip.hpp b/src/axom/primal/operators/clip.hpp
index b80a08408..d375a7371 100644
--- a/src/axom/primal/operators/clip.hpp
+++ b/src/axom/primal/operators/clip.hpp
@@ -51,9 +51,10 @@ Polygon<T, 3> clip(const Triangle<T, 3>& tri, const BoundingBox<T, 3>& bbox)
 
   // Use two polygons with pointers for 'back-buffer'-like swapping
   const int MAX_VERTS = 6;
-  PolygonType poly[2] = {PolygonType(MAX_VERTS), PolygonType(MAX_VERTS)};
-  PolygonType* currentPoly = &poly[0];
-  PolygonType* prevPoly = &poly[1];
+  PolygonType poly0(MAX_VERTS);
+  PolygonType poly1(MAX_VERTS);
+  PolygonType* currentPoly = &poly0;
+  PolygonType* prevPoly = &poly1;
 
   // First check if the triangle is contained in the bbox, if not we are empty
   BoundingBoxType triBox;

If not, since you mentioned Umpire, would it be possible to rebuild your application with additional Umpire diagnostics enabled?

[agcapps]

Thanks. You're right; it's not a lot to go on. I'll see if the user can try out the suggestion.

[agcapps]

Some more details:

• user has a workaround: setting OMP_NUM_THREADS=1 avoids this particular crash
• this is on BlueOS; yes, Umpire is present. Not sure if we can get Umpire diags going.
• host compiler is IBM Clang 14.0.5 with XL 2022.08.19
• device compiler is nvcc from CUDA 11.7
• I will see about getting a reproducer

[rhornung67]

is setting omp num threads to 1 a clue that there may be a memory (or thread safety) isssue in the in-out implementation?

[agcapps]

I have been unable to reproduce the crash with the Umpire error message "Cannot find allocator for pointer: ." In the meantime, several fixes (in particular, those upstreamed to us in #1204 ) went in to the copy of Axom. I propose to close this bug, to be reopened if the problem reappears.

[agcapps]

Closing as can't reproduce.