diff options
| -rw-r--r-- | rts/PrimOps.cmm | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/rts/PrimOps.cmm b/rts/PrimOps.cmm index a5d8553e94..625f5f5ab3 100644 --- a/rts/PrimOps.cmm +++ b/rts/PrimOps.cmm @@ -1893,14 +1893,25 @@ stg_makeStableNamezh ( P_ obj ) { W_ index, sn_obj; + MAYBE_GC_P(stg_makeStableNamezh, obj); + (index) = ccall lookupStableName(obj "ptr"); /* Is there already a StableName for this heap object? * stable_name_table is a pointer to an array of snEntry structs. */ if ( snEntry_sn_obj(W_[stable_name_table] + index*SIZEOF_snEntry) == NULL ) { - ALLOC_PRIM (SIZEOF_StgStableName); - sn_obj = Hp - SIZEOF_StgStableName + WDS(1); + // At this point we have a snEntry, but it doesn't look as used to the + // GC yet because we don't have a StableName object for the sn_obj field + // (remember that sn_obj == NULL means the entry is free). So if we call + // GC here we end up skipping the snEntry in gcStableNameTable(). This + // caused #15906. Solution: use allocate(), which does not call GC. + // + // (Alternatively we could use a special value for the sn_obj field to + // indicate that the entry is being allocated and not free, but that's + // too complicated and doesn't buy us much. See D5342?id=18700.) + ("ptr" sn_obj) = ccall allocate(MyCapability() "ptr", + BYTES_TO_WDS(SIZEOF_StgStableName)); SET_HDR(sn_obj, stg_STABLE_NAME_info, CCCS); StgStableName_sn(sn_obj) = index; snEntry_sn_obj(W_[stable_name_table] + index*SIZEOF_snEntry) = sn_obj; |