The panic code would panic again because a backend object which it no
longer owned was still referenced in thread local storage (don't we
all love abiguous acronyms?).

Example:

 #5  0x0000563d8c20d595 in VAS_Fail (func=0x563d8c23fd13 "vsl_sanity", file=0x563d8c23f9f5 "cache/cache_shmlog.c",
     line=110, cond=0x563d8c23fd1e "(vsl->wlp) != 0", kind=VAS_ASSERT) at vas.c:67
 #6  0x0000563d8c1603e9 in vsl_sanity (vsl=0x7fabd08001f0) at cache/cache_shmlog.c:110
 ...
 #7  0x0000563d8c160298 in VSL_Flush (vsl=0x7fabd08001f0, overflow=0) at cache/cache_shmlog.c:314
 #8  0x0000563d8c14dd44 in pan_ic (func=0x563d8c23c596 "child_signal_handler",
     file=0x563d8c23c1b4 "cache/cache_main.c", line=323,
     cond=0x7fabdf24a590 "Signal 6 (Aborted) received at 0x3e800015528 si_code -6", kind=VAS_WRONG)
     at cache/cache_panic.c:814
 ...
 #19 0x0000563d8c14bc07 in ObjBocDone (wrk=0x7fabdc9e54b8, oc=0x7fabd0024180, boc=0x7fabdc9e4778)
     at cache/cache_obj.c:368
 #20 0x0000563d8c13f25b in HSH_DerefBoc (wrk=0x7fabdc9e54b8, oc=0x7fabd0024180) at cache/cache_hash.c:1014
 #21 0x0000563d8c13158f in VBF_Fetch (wrk=0x7fabdc9e54b8, req=0x7fabd0008b20, oc=0x7fabd0024180, oldoc=0x0,
     mode=VBF_PASS) at cache/cache_fetch.c:1204
 #22 0x0000563d8c158f7d in cnt_pass (wrk=0x7fabdc9e54b8, req=0x7fabd0008b20) at cache/cache_req_fsm.c:742
 #23 0x0000563d8c156f53 in CNT_Request (req=0x7fabd0008b20) at cache/cache_req_fsm.c:1182
 #24 0x0000563d8c198f9a in HTTP1_Session (wrk=0x7fabdc9e54b8, req=0x7fabd0008b20) at http1/cache_http1_fsm.c:390
 #25 0x0000563d8c1984e0 in http1_req (wrk=0x7fabdc9e54b8, arg=0x7fabd0008b20) at http1/cache_http1_fsm.c:88
 #26 0x0000563d8c189592 in Pool_Work_Thread (pp=0x7fabdc400140, wrk=0x7fabdc9e54b8) at cache/cache_wrk.c:487
 #27 0x0000563d8c188ca7 in WRK_Thread (qp=0x7fabdc400140, stacksize=81920, thread_workspace=2048)
     at cache/cache_wrk.c:153