Rare crashes while popping a solver frame

[daniel-raffler]

Hello,

We've seen some rare crashes in Yices while popping a frame from the solver stack:

Stack: [0x00007508800f9000,0x00007508801f9000],  sp=0x00007508801f6280,  free space=1012k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C  [libyices2java.so+0x1a5fbb]  good_term_idx+0x35
C  [libyices2java.so+0x1accca]  good_term+0x2d
C  [libyices2java.so+0x1e5660]  variable_db_is_variable+0x156
C  [libyices2java.so+0x2d9c99]  clause_check+0x3d
C  [libyices2java.so+0x2da3fa]  clause_db_is_clause+0x115
C  [libyices2java.so+0x2da0f4]  clause_db_gc_sweep+0x98
C  [libyices2java.so+0x1f8db5]  bool_plugin_gc_sweep+0x6d
C  [libyices2java.so+0x1de701]  mcsat_gc+0x641
C  [libyices2java.so+0x1dd981]  mcsat_pop+0x19e
C  [libyices2java.so+0x55bb0]  context_pop+0x8c
C  [libyices2java.so+0x3903d]  yices_pop+0x123
C  [libyices2java.so+0x1f3c5]  Java_com_sri_yices_Yices_pop+0x2c
J 7749  com.sri.yices.Yices.pop(J)I (0 bytes) @ 0x000075086c71d5da [0x000075086c71d520+0x00000000000000ba]

The problem is non-deterministic and hard to reproduce. Could this be a locking issue?