bt #0 0x0000000000a0ed5d in StgRunIsImplementedInAssembler () at rts/StgCRun.c:370 #1 0x0000000000a0226a in schedule (initialCapability=0xd2c600 <MainCapability>, task=0x242dd70) at rts/Schedule.c:452 #2 0x0000000000a03b7b in scheduleWaitThread (tso=0x4200105370, ret=0x0,
print (StgClosure*)$rbx $27 = (StgClosure *) 0x42000b2868 print *(StgClosure*)$rbx $28 = {
#15508: concprog001 fails with various errors -------------------------------------+------------------------------------- Reporter: osa1 | Owner: osa1 Type: bug | Status: merge Priority: highest | Milestone: 8.8.1 Component: Compiler | Version: 8.5 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Runtime crash | Test Case: Blocked By: | Blocking: Related Tickets: #15571 | Differential Rev(s): Phab:D5051 | (reverted), Phab:D5165, Phab:D5178, Wiki Page: | MR:103 -------------------------------------+------------------------------------- Comment (by osa1): Here are some notes. Compile and run: {{{ ghc-stage2 Mult.hs -prof -fprof-auto -fforce-recomp -debug && ./Mult +RTS -DS }}} At one point we do a GC and continue: {{{ pcap=0x7ffdbfd88f10) at rts/Schedule.c:2547 #3 0x0000000000a15e4b in rts_evalLazyIO (cap=0x7ffdbfd88f10, p=0xb3bb98, ret=0x0) at rts/RtsAPI.c:530 #4 0x0000000000a175d3 in hs_main (argc=1, argv=0x7ffdbfd89108, main_closure=0xb3bb98, rts_config=...) at rts/RtsMain.c:72 #5 0x0000000000463e78 in main () }}} If I step a few instructions I see these instructions being executed {{{ 0x0000000000a35d60 stg_ap_0_fast+336 mov 0x8(%rbp),%rax 0x0000000000a35d64 stg_ap_0_fast+340 mov 0x10(%rbp),%rbx 0x0000000000a35d68 stg_ap_0_fast+344 mov 0x18(%rbp),%rcx 0x0000000000a35d6c stg_ap_0_fast+348 add $0x20,%rbp 0x0000000000a35d70 stg_ap_0_fast+352 mov %rcx,%rdx }}} This is in `stg_ap_0_fast` and `%rbx` is supposed to be a FUN for a PAP, but it's actually collected by the GC: {{{ header = { info = 0xaaaaaaaaaaaaaaaa, prof = { ccs = 0xaaaaaaaaaaaaaaaa, hp = { rs = 0xaaaaaaaaaaaaaaaa, ldvw = 12297829382473034410 } } }, payload = 0x42000b2880 } }}} Interestingly only some part of it is collected (the first 3 words). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15508#comment:40 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler