Segfault for rectangular `lq` factorizations

[lkdvos]

The following gives an error, but only sometimes:

using MatrixAlgebraKit
A = rand(20, 6)
lq_full(A)

julia> versioninfo()
Julia Version 1.11.4
Commit 8561cc3d68d (2025-03-10 11:36 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: macOS (arm64-apple-darwin24.0.0)
  CPU: 16 × Apple M3 Max
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, apple-m2)
Threads: 4 default, 0 interactive, 2 GC (on 12 virtual cores)
Environment:
  JULIA_EDITOR = code
  JULIA_NUM_THREADS = 4

❯ julia --startup-file=no --project=. -E 'using MatrixAlgebraKit; A = rand(20, 6); lq_full(A)'

[99539] signal 11 (2): Segmentation fault: 11
in expression starting at none:0
jl_gc_pool_alloc_inner at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/gc.c:1337 [inlined]
jl_gc_pool_alloc_noinline at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/gc.c:1394 [inlined]
jl_gc_alloc_ at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/./julia_internal.h:523
_new_genericmemory_ at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/genericmemory.c:56
GenericMemory at ./boot.jl:516 [inlined]
Array at ./boot.jl:578 [inlined]
InferenceState at ./compiler/inferencestate.jl:303
InferenceState at ./compiler/inferencestate.jl:500
typeinf_edge at ./compiler/typeinfer.jl:913
abstract_call_method at ./compiler/abstractinterpretation.jl:660
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:102
abstract_call_known at ./compiler/abstractinterpretation.jl:2200
abstract_call at ./compiler/abstractinterpretation.jl:2282
abstract_call at ./compiler/abstractinterpretation.jl:2275
abstract_call at ./compiler/abstractinterpretation.jl:2423
abstract_eval_call at ./compiler/abstractinterpretation.jl:2438
abstract_eval_statement_expr at ./compiler/abstractinterpretation.jl:2454
abstract_eval_statement at ./compiler/abstractinterpretation.jl:2752
abstract_eval_basic_statement at ./compiler/abstractinterpretation.jl:3068
typeinf_local at ./compiler/abstractinterpretation.jl:3331
typeinf_nocycle at ./compiler/abstractinterpretation.jl:3413
_typeinf at ./compiler/typeinfer.jl:244
typeinf at ./compiler/typeinfer.jl:215
typeinf_edge at ./compiler/typeinfer.jl:923
abstract_call_method at ./compiler/abstractinterpretation.jl:660
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:102
abstract_call_known at ./compiler/abstractinterpretation.jl:2200
abstract_call at ./compiler/abstractinterpretation.jl:2282
abstract_call at ./compiler/abstractinterpretation.jl:2275
abstract_call at ./compiler/abstractinterpretation.jl:2423
abstract_eval_call at ./compiler/abstractinterpretation.jl:2438
abstract_eval_statement_expr at ./compiler/abstractinterpretation.jl:2454
abstract_eval_statement at ./compiler/abstractinterpretation.jl:2752
abstract_eval_basic_statement at ./compiler/abstractinterpretation.jl:3068
typeinf_local at ./compiler/abstractinterpretation.jl:3331
typeinf_nocycle at ./compiler/abstractinterpretation.jl:3413
_typeinf at ./compiler/typeinfer.jl:244
typeinf at ./compiler/typeinfer.jl:215
typeinf_edge at ./compiler/typeinfer.jl:923
abstract_call_method at ./compiler/abstractinterpretation.jl:660
abstract_call_gf_by_type at ./compiler/abstractinterpretation.jl:102
abstract_call_known at ./compiler/abstractinterpretation.jl:2200
abstract_call at ./compiler/abstractinterpretation.jl:2282
abstract_call at ./compiler/abstractinterpretation.jl:2275
abstract_call at ./compiler/abstractinterpretation.jl:2423
abstract_eval_call at ./compiler/abstractinterpretation.jl:2438
abstract_eval_statement_expr at ./compiler/abstractinterpretation.jl:2454
abstract_eval_statement at ./compiler/abstractinterpretation.jl:2752
abstract_eval_basic_statement at ./compiler/abstractinterpretation.jl:3068
typeinf_local at ./compiler/abstractinterpretation.jl:3331
typeinf_nocycle at ./compiler/abstractinterpretation.jl:3413
_typeinf at ./compiler/typeinfer.jl:244
typeinf at ./compiler/typeinfer.jl:215
typeinf_ext at ./compiler/typeinfer.jl:1101
typeinf_ext_toplevel at ./compiler/typeinfer.jl:1139
typeinf_ext_toplevel at ./compiler/typeinfer.jl:1135
jfptr_typeinf_ext_toplevel_40033.1 at /Users/ldevos/.julia/juliaup/julia-1.11.4+0.aarch64.apple.darwin14/lib/julia/sys.dylib (unknown line)
jl_apply at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/./julia.h:2157 [inlined]
jl_type_infer at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/gf.c:390
jl_generate_fptr_impl at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/jitlayers.cpp:519
jl_compile_method_internal at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/gf.c:2536
_jl_invoke at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/gf.c:2940 [inlined]
ijl_apply_generic at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/gf.c:3125
jl_apply at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/./julia.h:2157 [inlined]
jl_f__call_latest at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/builtins.c:875
#invokelatest#2 at ./essentials.jl:1055 [inlined]
invokelatest at ./essentials.jl:1052 [inlined]
exec_options at ./client.jl:298
_start at ./client.jl:531
jfptr__start_73863.1 at /Users/ldevos/.julia/juliaup/julia-1.11.4+0.aarch64.apple.darwin14/lib/julia/sys.dylib (unknown line)
jl_apply at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/./julia.h:2157 [inlined]
true_main at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/jlapi.c:900
jl_repl_entrypoint at /Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-XG3Q6T6R70.0/build/default-honeycrisp-XG3Q6T6R70-0/julialang/julia-release-1-dot-11/src/jlapi.c:1059
Allocations: 887501 (Pool: 887466; Big: 35); GC: 1
[1]    99539 segmentation fault  julia --startup-file=no --project=. -E 

[Jutho]

This seems very much like the same segfault I was getting when I was trying different blocksizes as parameter to the LQ decomposition. I don't know if there is an error in my ccall's to LAPACK, or whether there is really a bug in the LAPACK blocked LQ functions (which are pretty recent and probably not used that often).

[lkdvos]

Is there something I can do to help figure that out?

[Jutho]

If you can reproduce it locally, try playing with the blocksize keyword.

[lkdvos]

Fixed by 9df9060

See also: Reference-LAPACK/lapack#1113