2319552 - Abort in hos_sharedvar::UnLock - SAP IQ 15.4

Frequent fatal aborts on hos_sharedvar::UnLock on simple DELETE or LOAD TABLE.

There are 2 variants of stack traces.

The 2 stack traces below are from 2 simple deletes with 1 table involved.

ABORT 1

pcpstack
DumpAllThreads
hos_ABORT
ThrowAbort
Throw
hos_sharedvar::UnLock
s_bufpool::MoveToEmptyList
s_bufpartition::Destroy
s_blockmap::Destroy
s_pageListCursor::Delete
v2s_bmcontext::DeletePage
v2s_bmcontext::DeleteUnit
v2s_bmcontext::bmlev1sgblkoldselfdel
v2s_bmcontext::bmselfcpytail1
v2s_bmcontext::bmselfunion
s_bm::Or
s_BitmapMergeWorkDesc::MergeBitmaps
vpp_FindIter::DoOneBMWorkunit
vpp_FindIter::ExecWork
workAllocator::DoWork
hos_thread::Main
hos_lwtask::Start
IQWorkerStarter
W32Task::pre_body
BaseThreadInitThunk + 13
RtlUserThreadStart + 33

ABORT 2

pcpstack
DumpAllThreads
hos_ABORT
ThrowAbort
Throw
hos_sharedvar::UnLock
s_bufpool::MoveToUnlockedList
s_buf::UnlockUserLocked
s_buf::UnlockUser
s_pageListCursor::PositionPage
v2s_bmcontext::bmlfblkreset
v2s_bmcontext::bmselfreldif
s_bm::TurnOff
s_datetimeIndex::Delete
hdb_delete_indices::Unit_of_Work
hdb_delete_indices::hdb_delete_index_iter::ExecWork
workAllocator::DoWork
hos_thread::Main
hos_lwtask::Start
IQWorkerStarter
W32Task::pre_body
BaseThreadInitThunk + 13
RtlUserThreadStart + 33

SAP IQ 15.4 on Windows

CR798002 ; 798002 ; Emergency Buffer Pool ; EBP ; hos_sharedvar::UnLock ; hos_sharedvar ; UnLock ; s_bufpool::MoveToEmptyList ; s_bufpool ; MoveToEmptyList ; s_bufpartition::Destroy ; s_bufpartition ; Destroy ; s_blockmap::Destroy ; s_blockmap ; s_pageListCursor::Delete ; s_pageListCursor ; Delete ; v2s_bmcontext::DeletePage ; v2s_bmcontext ; DeletePage ; v2s_bmcontext::DeleteUnit ; DeleteUnit ; s_bufpool::MoveToUnlockedList ; MoveToUnlockedList ; s_buf::UnlockUserLocked ; s_buf::UnlockUser ; UnlockUserLocked ; UnlockUser ;   , KBA , BC-SYB-IQ , Sybase IQ , Problem