#5314: "internal error: heapCencus, unknown object: 0" with retainer profiling
-------------------------------+--------------------------------------------
Reporter: akio | Owner: simonmar
Type: bug | Status: new
Priority: high | Milestone: 7.2.1
Component: Runtime System | Version: 7.0.4
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Linux | Blocking:
Architecture: x86_64 (amd64) | Failure: Runtime crash
-------------------------------+--------------------------------------------
Changes (by igloo):
* owner: igloo => simonmar
Comment:
{{{
Breakpoint 3, heapCensusChain (census=0xcb3210, bd=0x7ffff6903e00)
at rts/ProfHeap.c:934
934 info = get_itbl((StgClosure *)p);
(gdb) n
935 prim = rtsFalse;
(gdb) p *info
$23 = {prof = {closure_type_off = 1090616, __pad_closure_type_off = 0,
closure_desc_off = 1090624, __pad_closure_desc_off = 0}, layout = {
payload = {ptrs = 1, nptrs = 0}, bitmap = 1, large_bitmap_offset = 1,
__pad_large_bitmap_offset = 1, selector_offset = 1}, type = 28,
srt_bitmap = 0, code = 0x8eefa0
"H\213[\030H\203\343\370\377#f\017\037D"}
(gdb) p p
$24 = (StgPtr) 0x7ffff69f8000
(gdb) pmem p 64
[...]
0x7ffff69f8088: 0xaaaaaaaaaaaaaaaa
0x7ffff69f8080: 0xaaaaaaaaaaaaaaaa
0x7ffff69f8078: 0xaaaaaaaaaaaaaaaa
0x7ffff69f8070: 0xaaaaaaaaaaaaaaaa
0x7ffff69f8068: 0x0
0x7ffff69f8060: 0xc15b28 <Main_CAFs_cc_ccs>
0x7ffff69f8058: 0x404618 <frame_dummy+1672>
0x7ffff69f8050: 0xc8bdc8 <stg_END_TSO_QUEUE_closure>
0x7ffff69f8048: 0xc8bdc8 <stg_END_TSO_QUEUE_closure>
0x7ffff69f8040: 0xc8bdc8 <stg_END_TSO_QUEUE_closure>
0x7ffff69f8038: 0x0
0x7ffff69f8030: 0xc15b28 <Main_CAFs_cc_ccs>
0x7ffff69f8028: 0x8ef628 <stg_MVAR_CLEAN_info>
0x7ffff69f8020: 0x7ffff69f93e0
0x7ffff69f8018: 0xc8bdc8 <stg_END_TSO_QUEUE_closure>
0x7ffff69f8010: 0x0
0x7ffff69f8008: 0xc8b500 <CCS_SYSTEM>
0x7ffff69f8000: 0x8eefa0 <stg_IND_info>
(gdb) p *bd
$25 = {start = 0x7ffff69f8000, free = 0x7ffff69f8078, link = 0x0, u = {
back = 0x7ffff69f8078, bitmap = 0x7ffff69f8078, scan =
0x7ffff69f8078},
gen = 0xc9e1a0, gen_no = 0, dest_no = 1, _pad1 = 0, flags = 1, blocks =
1,
_padding = {0, 0, 0}}
(gdb) n
937 switch (info->type) {
(gdb)
981 size = BLACKHOLE_sizeW();
(gdb)
982 break;
(gdb) p size
$26 = 4
(gdb) n
1066 heapProfObject(census,(StgClosure*)p,size,prim);
(gdb) p sizeof(StgInd)
$27 = 32
(gdb) n
1068 p += size;
(gdb)
933 while (p < bd->free) {
(gdb) p p
$28 = (StgPtr) 0x7ffff69f8020
}}}
To my untrained eye, it looks like p should probably actually have been
increased by 5. We went through this case; is the comment right?:
{{{
case IND:
// Special case/Delicate Hack: INDs don't normally
// appear, since we're doing this heap census right
// after GC. However, GarbageCollect() also does
// resurrectThreads(), which can update some
// blackholes when it calls raiseAsync() on the
// resurrected threads. So we know that any IND will
// be the size of a BLACKHOLE.
size = BLACKHOLE_sizeW();
break;
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5314#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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