BUG #4630: Null-pointer dereference on FreeBSD / PowerPC in PageIsPrunable ()

The following bug has been logged online:

Bug reference:      4630
Logged by:          Nick Withers
Email address:      nick@nickwithers.com
PostgreSQL version: 8.3.5
Operating system:   FreeBSD 7-STABLE
Description:        Null-pointer dereference on FreeBSD / PowerPC in
PageIsPrunable ()
Details:

Have been regularly getting segfaults on my lone FreeBSD PowerPC G4 (7400)
system for months.

This was reported to the general mailing list ().

PostgreSQL is used as a database backend for Bacula backups on this
machine.

I'm not knowledgeable enough to create a minimalist test case, and these
segfaults don't seem to be triggered reliably.

Here're a couple of backtraces:
____

internal# gdb postgres postgres.core
GNU gdb 6.1.1 [FreeBSD]
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for
details.
This GDB was configured as "powerpc-marcel-freebsd"...
Core was generated by `postgres'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /usr/local/lib/libintl.so.8...done.
Loaded symbols for /usr/local/lib/libintl.so.8
Reading symbols from /usr/local/lib/libxml2.so.5...done.
Loaded symbols for /usr/local/lib/libxml2.so.5
Reading symbols from /usr/lib/libssl.so.5...done.
Loaded symbols for /usr/lib/libssl.so.5
Reading symbols from /lib/libcrypto.so.5...done.
Loaded symbols for /lib/libcrypto.so.5
Reading symbols from /lib/libcrypt.so.4...done.
Loaded symbols for /lib/libcrypt.so.4
Reading symbols from /lib/libm.so.5...done.
Loaded symbols for /lib/libm.so.5
Reading symbols from /lib/libthr.so.3...done.
Loaded symbols for /lib/libthr.so.3
Reading symbols from /lib/libc.so.7...done.
Loaded symbols for /lib/libc.so.7
Reading symbols from /usr/local/lib/libiconv.so.3...done.
Loaded symbols for /usr/local/lib/libiconv.so.3
Reading symbols from /lib/libz.so.4...done.
Loaded symbols for /lib/libz.so.4
Reading symbols from /libexec/ld-elf.so.1...done.
Loaded symbols for /libexec/ld-elf.so.1
#0  0x0186a1ec in heap_page_prune_opt (relation=0x224c9f70, buffer=-1,
    OldestXmin=28440) at pruneheap.c:79
79 if (!PageIsPrunable(dp, OldestXmin))
[New Thread 0x22401100 (LWP 100093)]
(gdb) bt full
#0  0x0186a1ec in heap_page_prune_opt (relation=0x224c9f70, buffer=-1,
    OldestXmin=28440) at pruneheap.c:79
dp = 0x0
minfree = 4294967295
#1  0x0185f790 in heapgetpage (scan=0x22970d88, page=0) at heapam.c:216
buffer = -1
snapshot = 0x224af818
dp = 0x20100 <Address 0x20100 out of bounds>
lines = 184
ntup = 28449656
lineoff = 0
lpp = 0x10003
#2  0x01860848 in heapgettup_pagemode (scan=0x22970d88,
    dir=ForwardScanDirection, nkeys=0, key=0x0) at heapam.c:583
tuple = 0x22970dac
backward = 0 '\0'
page = 0
finished = 0 '\0'
dp = 0x3f <Address 0x3f out of bounds>
lines = 28315260
lineindex = 0
lineoff = 4
linesleft = 0
lpp = 0x19
#3  0x01861fa8 in heap_getnext (scan=0x22970d88,
    direction=ForwardScanDirection) at heapam.c:1269
No locals.
#4  0x019b39e8 in SeqNext (node=0x22970c50) at nodeSeqscan.c:92
tuple = 0x7fffd1c0
scandesc = 0x22970d88
scanrelid = 4
estate = (EState *) 0x224f3018
direction = ForwardScanDirection
slot = (TupleTableSlot *) 0x224f34b0
#5  0x019a07b8 in ExecScan (node=0x22970c50, accessMtd=0x19b38bc
<SeqNext>)
    at execScan.c:103
slot = (TupleTableSlot *) 0x168
econtext = (ExprContext *) 0x22970cd8
qual = (List *) 0x0
projInfo = (ProjectionInfo *) 0x229712c8
isDone = 580330028
resultSlot = (TupleTableSlot *) 0x7fffd1f0
#6  0x019b3a74 in ExecSeqScan (node=0x22970c50) at nodeSeqscan.c:130
No locals.
#7  0x01995530 in ExecProcNode (node=0x22970c50) at execProcnode.c:334
result = (TupleTableSlot *) 0x4e6958
__func__ = "ExecProcNode"
#8  0x019b46e4 in ExecSort (node=0x22970bc8) at nodeSort.c:102
plannode = (Sort *) 0x224ec828
outerNode = (PlanState *) 0x22970c50
tupDesc = 0x229711a0
estate = (EState *) 0x224f3018
dir = ForwardScanDirection
tuplesortstate = (Tuplesortstate *) 0x22972018
slot = (TupleTableSlot *) 0x224f4f70
#9  0x01995638 in ExecProcNode (node=0x22970bc8) at execProcnode.c:386
result = (TupleTableSlot *) 0x224d18d8
__func__ = "ExecProcNode"
#10 0x019b4c3c in ExecUnique (node=0x22970b40) at nodeUnique.c:69
plannode = (Unique *) 0x224ecd58
resultTupleSlot = (TupleTableSlot *) 0x224f33b0
slot = (TupleTableSlot *) 0xffd310
outerPlan = (PlanState *) 0x22970bc8
#11 0x01995680 in ExecProcNode (node=0x22970b40) at execProcnode.c:398
result = (TupleTableSlot *) 0x224f4f70
__func__ = "ExecProcNode"
#12 0x019b8db0 in SubqueryNext (node=0x224f4f70) at
nodeSubqueryscan.c:58
slot = (TupleTableSlot *) 0x224f4f70
#13 0x019a07b8 in ExecScan (node=0x224f4f70,
    accessMtd=0x19b8d88 <SubqueryNext>) at execScan.c:103
slot = (TupleTableSlot *) 0x224e6a70
econtext = (ExprContext *) 0x22970080
qual = (List *) 0x22970b28
projInfo = (ProjectionInfo *) 0x22971710
isDone = 575586072
resultSlot = (TupleTableSlot *) 0x19
#14 0x019b8e14 in ExecSubqueryScan (node=0x224f4f70) at
nodeSubqueryscan.c:85
No locals.
#15 0x01995590 in ExecProcNode (node=0x224f4f70) at execProcnode.c:352
result = (TupleTableSlot *) 0x224f4f70
__func__ = "ExecProcNode"
#16 0x01992868 in ExecutePlan (estate=0x224f3018, planstate=0x224f4f70,
    operation=CMD_INSERT, numberTuples=0,
direction=ForwardScanDirection,
    dest=0x224ed840) at execMain.c:1335
junkfilter = (JunkFilter *) 0x2000
planSlot = (TupleTableSlot *) 0xb
slot = (TupleTableSlot *) 0x224eb8b8
tupleid = 0x0
tuple_ctid = {ip_blkid = {bi_hi = 0, bi_lo = 128}, ip_posid = 0}
current_tuple_count = 0
result = (TupleTableSlot *) 0x0
__func__ = "ExecutePlan"
#17 0x01990a14 in ExecutorRun (queryDesc=0x224af840,
    direction=ForwardScanDirection, count=0) at execMain.c:270
estate = (EState *) 0x224f3018
operation = CMD_INSERT
dest = (DestReceiver *) 0x224ed840
sendTuples = 0 '\0'
result = (TupleTableSlot *) 0x7fffd510
oldcontext = 0x224d17c8
#18 0x01aa17fc in ProcessQuery (plan=0x224ed7d0, params=0x0,
dest=0x224ed840,
    completionTag=0x7fffd81e "") at pquery.c:179
queryDesc = (QueryDesc *) 0x224af840
__func__ = "ProcessQuery"
#19 0x01aa3494 in PortalRunMulti (portal=0x224d7018, isTopLevel=1
'\001',
    dest=0x224ed840, altdest=0x224ed840, completionTag=0x7fffd81e "")
    at pquery.c:1242
pstmt = (PlannedStmt *) 0x224ed7d0
stmt = (Node *) 0x224ed7d0
stmtlist_item = (ListCell *) 0x224ed818
#20 0x01aa2910 in PortalRun (portal=0x224d7018, count=2147483647,
    isTopLevel=1 '\001', dest=0x224ed840, altdest=0x224ed840,
    completionTag=0x7fffd81e "") at pquery.c:813
save_exception_stack = (sigjmp_buf *) 0x7fffd920
save_context_stack = (ErrorContextCallback *) 0x0
local_sigjmp_buf = {{_sjb = {0, 2147473696, 0, 2147472896, 574843656,
      567325576, 2147472832, 27928436, 671088770, 0 <repeats 16 times>,
3,
      2147474872, 2147472832, 0, 0, 0, 0, 0, 0, 3, 2147474872,
2147472864, 3,
      575447184, 2147473040, 2147473088, 3, 4, 2147473056, 4, 575477696,
0,
      574816384, 2147473104, 1, 574816384, 2147473088, 2147473136,
27060864,
      3, 2147473104, 2147473152, 3, 0, 575180896, 4, 575477832,
575180824,
      2147473136, 2147473232, 14, 574816384, 2147473152, 2147473264,
22472,
      575477800, 64, 3, 575592504, 575582208, 574843656, 0, 14,
574843656, 40,
      575592512, 575477928, 575180824, 29967036, 0, 3, 2147473312,
2147473232,
      2147473264, 29295016, 574843656, 40, 0, 3, 575477840, 2147473264,
      2147473312, 25429760, 575592512, 29967036, 2147473344}}}
result = 127 '\177'
saveTopTransactionResourceOwner = 0x224d1488
saveTopTransactionContext = 0x22436b90
saveActivePortal = 0x0
saveActiveSnapshot = 0x0
saveResourceOwner = 0x224d1488
savePortalContext = 0x0
saveMemoryContext = 0x22436b90
__func__ = "PortalRun"
#21 0x01a9bae4 in exec_simple_query (
    query_string=0x22493018 "INSERT INTO Path (Path) SELECT a.Path FROM
(SELECT DISTINCT Path FROM batch) AS a WHERE NOT EXISTS (SELECT Path
FROM Path WHERE Path = a.Path) ") at postgres.c:986
parsetree = (Node *) 0x22494090
portal = 0x224d7018
commandTag = 0x1c9618c "INSERT"
completionTag = "\000
\177��P\001\234��\"I0\030\000\000\000\217\"I0\030
\001\234�X\000\000\000\000\000\000\000T\177��P\000\000\000\003A�\v&
\177��P\177��\200\001\234��\000\000\000\217\"I"
querytree_list = (List *) 0x224e5c28
plantree_list = (List *) 0x224ed828
receiver = (DestReceiver *) 0x224ed840
format = 0
dest = DestRemote
oldcontext = 0x22436b90
parsetree_list = (List *) 0x224940c8
parsetree_item = (ListCell *) 0x224940b8
save_log_statement_stats = 0 '\0'
was_logged = 0 '\0'
isTopLevel = 1 '\001'
msec_str = "\"I0\030\000\000\000\217\000\000\000\003\000\000\000\000
\177��\020\177��P\001��l\000\000\000Q"
__func__ = "exec_simple_query"
#22 0x01aa08b0 in PostgresMain (argc=4, argv=0x22433630,
    username=0x22433610 "bacula") at postgres.c:3572
query_string = 0x22493018 "INSERT INTO Path (Path) SELECT a.Path FROM
(SELECT DISTINCT Path FROM batch) AS a WHERE NOT EXISTS (SELECT Path
FROM Path WHERE Path = a.Path) "
flag = -1
dbname = 0x2241e128 "bacula"
userDoption = 0x0
secure = 0 '\0'
errs = 0
debug_flag = -1
guc_names = (List *) 0x0
guc_values = (List *) 0x0
ctx = PGC_USERSET
gucsource = PGC_S_CLIENT
am_superuser = 0 '\0'
firstchar = 81
stack_base = 0 '\0'
input_message = {
  data = 0x22493018 "INSERT INTO Path (Path) SELECT a.Path FROM (SELECT
DISTINCT Path FROM batch) AS a WHERE NOT EXISTS (SELECT Path FROM Path
WHERE Path = a.Path) ", len = 144, maxlen = 1024, cursor = 144}
local_sigjmp_buf = {{_sjb = {1, 2147151939, -1, -1, -1, 567325576,
      2147473536, 27919876, 1207959620, 0 <repeats 16 times>, 3,
2147474872,
      2147473536, 0, 29945672, 2147474872, 0, 2147474192, 572907720,
67108864,
      2147474200, 2147473872, 0, 574620516, 30567600, 23, 34144255,
573125272,
      4095, 2147473968, 574624000, 571861904, 939524226, 0, 571861780,
      572989924, 61490, 2147473936, 167772160, 3072, 0, 0, 0, 0, 0,
30567552,
      573164272, 30264272, 574619648, 574840832, 30567552, 573125272,
      574620296, 2147474016, 572458996, 0, 0, 2147474032, 0, 4,
574619648, 0,
      574840832, 0, 574620296, 2147474080, 572459680, 0, 2147474032,
      2147474096, 0, 4, 0, 0, 574824600, 574816384, 0, 0, 3, 574816384,
      574824608, 2147474112, 29289624, 12, 18, 0}}}
send_ready_for_query = 0 '\0'
__func__ = "PostgresMain"
#23 0x01a56748 in BackendRun (port=0x22407400) at postmaster.c:3207
av = (char **) 0x22433630
maxac = 10
ac = 4
secs = 285943416
usecs = 894679
protobuf = "-v196608\000@t\000\001�� \"C6
\"C6\020\000\000\000@\001��X"
i = 4
__func__ = "BackendRun"
#24 0x01a55988 in BackendStartup (port=0x22407400) at postmaster.c:2830
bn = (Backend *) 0x224051d0
pid = 0
__func__ = "BackendStartup"
#25 0x01a52994 in ServerLoop () at postmaster.c:1274
port = (Port *) 0x22407400
i = 2
rmask = {__fds_bits = {32, 0 <repeats 31 times>}}
selres = 1
readmask = {__fds_bits = {56, 0 <repeats 31 times>}}
nSockets = 6
now = 1232628203
last_touch_time = 1232626270
__func__ = "ServerLoop"
#26 0x01a52198 in PostmasterMain (argc=3, argv=0x7fffdda8) at
postmaster.c:1029
opt = -1
status = 0
userDoption = 0x7fffde6f "/usr/local/pgsql/data"
i = 64
__func__ = "PostmasterMain"
#27 0x019ce288 in main (argc=3, argv=0x7fffdda8) at main.c:188
No locals.
____

____

internal# gdb postgres postgres.core
GNU gdb 6.1.1 [FreeBSD]
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "powerpc-marcel-freebsd"...
Core was generated by `postgres'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /usr/local/lib/libintl.so.8...done.
Loaded symbols for /usr/local/lib/libintl.so.8
Reading symbols from /usr/local/lib/libxml2.so.5...done.
Loaded symbols for /usr/local/lib/libxml2.so.5
Reading symbols from /usr/lib/libssl.so.5...done.
Loaded symbols for /usr/lib/libssl.so.5
Reading symbols from /lib/libcrypto.so.5...done.
Loaded symbols for /lib/libcrypto.so.5
Reading symbols from /lib/libcrypt.so.4...done.
Loaded symbols for /lib/libcrypt.so.4
Reading symbols from /lib/libm.so.5...done.
Loaded symbols for /lib/libm.so.5
Reading symbols from /lib/libthr.so.3...done.
Loaded symbols for /lib/libthr.so.3
Reading symbols from /lib/libc.so.7...done.
Loaded symbols for /lib/libc.so.7
Reading symbols from /usr/local/lib/libiconv.so.3...done.
Loaded symbols for /usr/local/lib/libiconv.so.3
Reading symbols from /lib/libz.so.4...done.
Loaded symbols for /lib/libz.so.4
Reading symbols from /libexec/ld-elf.so.1...done.
Loaded symbols for /libexec/ld-elf.so.1
#0  0x0186a1ec in heap_page_prune_opt (relation=0x224caf70, buffer=-1,
OldestXmin=29088) at pruneheap.c:79
79        if (!PageIsPrunable(dp, OldestXmin))
[New Thread 0x22401100 (LWP 100117)]
(gdb) bt full
#0  0x0186a1ec in heap_page_prune_opt (relation=0x224caf70, buffer=-1,
OldestXmin=29088) at pruneheap.c:79
    dp = 0x0
    minfree = 4294967295
#1  0x0185f790 in heapgetpage (scan=0x22972d88, page=0) at heapam.c:216
    buffer = -1
    snapshot = 0x224b0818
    dp = 0x20100 <Address 0x20100 out of bounds>
    lines = 184
    ntup = 28449656
    lineoff = 0
    lpp = 0x10003
#2  0x01860848 in heapgettup_pagemode (scan=0x22972d88,
dir=ForwardScanDirection, nkeys=0, key=0x0) at heapam.c:583
    tuple = 0x22972dac
    backward = 0 '\0'
    page = 0
    finished = 0 '\0'
    dp = 0x3f <Address 0x3f out of bounds>
    lines = 28315260
    lineindex = 0
    lineoff = 4
    linesleft = 0
    lpp = 0x19
#3  0x01861fa8 in heap_getnext (scan=0x22972d88,
direction=ForwardScanDirection) at heapam.c:1269
No locals.
#4  0x019b39e8 in SeqNext (node=0x22972c50) at nodeSeqscan.c:92
    tuple = 0x7fffd1d0
    scandesc = 0x22972d88
    scanrelid = 4
    estate = (EState *) 0x2296e018
    direction = ForwardScanDirection
    slot = (TupleTableSlot *) 0x2296e4b0
#5  0x019a07b8 in ExecScan (node=0x22972c50, accessMtd=0x19b38bc <SeqNext>)
at execScan.c:103
    slot = (TupleTableSlot *) 0x168
    econtext = (ExprContext *) 0x22972cd8
    qual = (List *) 0x0
    projInfo = (ProjectionInfo *) 0x229732c8
    isDone = 580338220
    resultSlot = (TupleTableSlot *) 0x7fffd200
#6  0x019b3a74 in ExecSeqScan (node=0x22972c50) at nodeSeqscan.c:130
No locals.
#7  0x01995530 in ExecProcNode (node=0x22972c50) at execProcnode.c:334
    result = (TupleTableSlot *) 0x4e7958
    __func__ = "ExecProcNode"
#8  0x019b46e4 in ExecSort (node=0x22972bc8) at nodeSort.c:102
    plannode = (Sort *) 0x224ef828
    outerNode = (PlanState *) 0x22972c50
    tupDesc = 0x229731a0
    estate = (EState *) 0x2296e018
    dir = ForwardScanDirection
    tuplesortstate = (Tuplesortstate *) 0x22974018
    slot = (TupleTableSlot *) 0x2296ff70
#9  0x01995638 in ExecProcNode (node=0x22972bc8) at execProcnode.c:386
    result = (TupleTableSlot *) 0x224d28f8
    __func__ = "ExecProcNode"
#10 0x019b4c3c in ExecUnique (node=0x22972b40) at nodeUnique.c:69
    plannode = (Unique *) 0x224efd58
    resultTupleSlot = (TupleTableSlot *) 0x2296e3b0
    slot = (TupleTableSlot *) 0xffd320
    outerPlan = (PlanState *) 0x22972bc8
#11 0x01995680 in ExecProcNode (node=0x22972b40) at execProcnode.c:398
    result = (TupleTableSlot *) 0x2296ff70
    __func__ = "ExecProcNode"
#12 0x019b8db0 in SubqueryNext (node=0x2296ff70) at nodeSubqueryscan.c:58
    slot = (TupleTableSlot *) 0x2296ff70
#13 0x019a07b8 in ExecScan (node=0x2296ff70, accessMtd=0x19b8d88
<SubqueryNext>) at execScan.c:103
    slot = (TupleTableSlot *) 0x224e7a70
    econtext = (ExprContext *) 0x22972080
    qual = (List *) 0x22972b28
    projInfo = (ProjectionInfo *) 0x22973710
    isDone = 575598360
    resultSlot = (TupleTableSlot *) 0x19
#14 0x019b8e14 in ExecSubqueryScan (node=0x2296ff70) at
nodeSubqueryscan.c:85
No locals.
#15 0x01995590 in ExecProcNode (node=0x2296ff70) at execProcnode.c:352
    result = (TupleTableSlot *) 0x2296ff70
    __func__ = "ExecProcNode"
#16 0x01992868 in ExecutePlan (estate=0x2296e018, planstate=0x2296ff70,
operation=CMD_INSERT, numberTuples=0,
    direction=ForwardScanDirection, dest=0x224f0840) at execMain.c:1335
    junkfilter = (JunkFilter *) 0x2000
    planSlot = (TupleTableSlot *) 0xb
    slot = (TupleTableSlot *) 0x224ee8b8
    tupleid = 0x0
    tuple_ctid = {ip_blkid = {bi_hi = 0, bi_lo = 128}, ip_posid = 0}
    current_tuple_count = 0
    result = (TupleTableSlot *) 0x0
    __func__ = "ExecutePlan"
#17 0x01990a14 in ExecutorRun (queryDesc=0x224b0840,
direction=ForwardScanDirection, count=0) at execMain.c:270
    estate = (EState *) 0x2296e018
    operation = CMD_INSERT
    dest = (DestReceiver *) 0x224f0840
    sendTuples = 0 '\0'
    result = (TupleTableSlot *) 0x7fffd520
    oldcontext = 0x224d27e8
#18 0x01aa17fc in ProcessQuery (plan=0x224f07d0, params=0x0,
dest=0x224f0840, completionTag=0x7fffd82e "") at pquery.c:179
    queryDesc = (QueryDesc *) 0x224b0840
    __func__ = "ProcessQuery"
#19 0x01aa3494 in PortalRunMulti (portal=0x224d8018, isTopLevel=1 '\001',
dest=0x224f0840, altdest=0x224f0840,
    completionTag=0x7fffd82e "") at pquery.c:1242
    pstmt = (PlannedStmt *) 0x224f07d0
    stmt = (Node *) 0x224f07d0
    stmtlist_item = (ListCell *) 0x224f0818
#20 0x01aa2910 in PortalRun (portal=0x224d8018, count=2147483647,
isTopLevel=1 '\001', dest=0x224f0840, altdest=0x224f0840,
    completionTag=0x7fffd82e "") at pquery.c:813
    save_exception_stack = (sigjmp_buf *) 0x7fffd930
    save_context_stack = (ErrorContextCallback *) 0x0
    local_sigjmp_buf = {{_sjb = {0, 2147473712, 0, 2147472912, 574847712,
567325576, 2147472848, 27928436, 671088770,
      0 <repeats 16 times>, 3, 2147474884, 2147472848, 0, 0, 0, 0, 0, 0, 3,
2147474884, 2147472880, 3, 575451280, 2147473056,
      2147473104, 3, 4, 2147473072, 4, 575481824, 0, 574816384, 2147473120,
1, 574816384, 2147473104, 2147473152, 27060864, 3,
      2147473120, 2147473168, 3, 0, 575184992, 4, 575481960, 575184920,
2147473152, 2147473248, 14, 574816384, 2147473168,
      2147473280, 22472, 575481928, 64, 3, 575604792, 575594496, 574847712,
0, 14, 574847712, 40, 575604800, 575482056, 575184920,
      29967036, 0, 3, 2147473328, 2147473248, 2147473280, 29295016,
574847712, 40, 0, 3, 575481968, 2147473280, 2147473328,
      25429760, 575604800, 29967036, 2147473360}}}
    result = 127 '\177'
    saveTopTransactionResourceOwner = 0x224d24d0
    saveTopTransactionContext = 0x22437b68
    saveActivePortal = 0x0
    saveActiveSnapshot = 0x0
    saveResourceOwner = 0x224d24d0
    savePortalContext = 0x0
    saveMemoryContext = 0x22437b68
    __func__ = "PortalRun"
#21 0x01a9bae4 in exec_simple_query (
    query_string=0x22494018 "INSERT INTO Path (Path) SELECT a.Path FROM
(SELECT DISTINCT Path FROM batch) AS a WHERE NOT EXISTS (SELECT Path FROM
Path WHERE Path = a.Path) ") at postgres.c:986
    parsetree = (Node *) 0x22495090
    portal = 0x224d8018
    commandTag = 0x1c9618c "INSERT"
    completionTag =
"\0000\177��`\001\234��\"I@\030\000\000\000\217\"I@\030\001\234�X\
000\000\000\000\000\000\000T\177��`\000\000\000\003A�\020g\177��`\
177��\220\001\234��\000\000\000\217\"I"
    querytree_list = (List *) 0x224e6c28
    plantree_list = (List *) 0x224f0828
    receiver = (DestReceiver *) 0x224f0840
    format = 0
    dest = DestRemote
    oldcontext = 0x22437b68
    parsetree_list = (List *) 0x224950c8
    parsetree_item = (ListCell *) 0x224950b8
    save_log_statement_stats = 0 '\0'
    was_logged = 0 '\0'
    isTopLevel = 1 '\001'
    msec_str =
"\"I@\030\000\000\000\217\000\000\000\003\000\000\000\000\177��
\177��`\001��l\000\000\000Q"
    __func__ = "exec_simple_query"
#22 0x01aa08b0 in PostgresMain (argc=4, argv=0x22433448, username=0x22433428
"bacula") at postgres.c:3572
    query_string = 0x22494018 "INSERT INTO Path (Path) SELECT a.Path FROM
(SELECT DISTINCT Path FROM batch) AS a WHERE NOT EXISTS (SELECT Path FROM
Path WHERE Path = a.Path) "
    flag = -1
    dbname = 0x2241e128 "bacula"
    userDoption = 0x0
    secure = 0 '\0'
    errs = 0
    debug_flag = -1
    guc_names = (List *) 0x0
    guc_values = (List *) 0x0
    ctx = PGC_USERSET
    gucsource = PGC_S_CLIENT
    am_superuser = 0 '\0'
    firstchar = 81
    stack_base = 0 '\0'
    input_message = {
  data = 0x22494018 "INSERT INTO Path (Path) SELECT a.Path FROM (SELECT
DISTINCT Path FROM batch) AS a WHERE NOT EXISTS (SELECT Path FROM Path WHERE
Path = a.Path) ", len = 144, maxlen = 1024, cursor = 144}
    local_sigjmp_buf = {{_sjb = {1, 2147151939, -1, -1, -1, 567325576,
2147473552, 27919876, 1207959620, 0 <repeats 16 times>,
      3, 2147474884, 2147473552, 0, 29945672, 2147474884, 0, 2147474208,
572899220, 67108864, 2147474216, 2147473888, 0, 574620528,
      30567600, 23, 34144255, 573115328, 4095, 2147473984, 574624000,
571857500, 939524226, 0, 571857376, 572981424, 61490,
      2147473952, 167772160, 3072, 0, 0, 0, 0, 0, 30567552, 573154328,
30264272, 574619648, 574844928, 30567552, 573115328,
      574620308, 2147474032, 572450496, 0, 0, 2147474048, 0, 4, 574619648,
0, 574844928, 0, 574620308, 2147474096, 572451180, 0,
      2147474048, 2147474112, 0, 4, 0, 0, 574824600, 574816384, 0, 0, 3,
574816384, 574824608, 2147474128, 29289624, 12, 18, 0}}}
    send_ready_for_query = 0 '\0'
    __func__ = "PostgresMain"
#23 0x01a56748 in BackendRun (port=0x22407400) at postmaster.c:3207
    av = (char **) 0x22433448
    maxac = 10
    ac = 4
    secs = 286287712
    usecs = 586255
    protobuf = "-v196608\000@t\000\001��
\"C48\"C4(\000\000\000@\001��X"
    i = 4
    __func__ = "BackendRun"
#24 0x01a55988 in BackendStartup (port=0x22407400) at postmaster.c:2830
    bn = (Backend *) 0x224051c0
    pid = 0
    __func__ = "BackendStartup"
#25 0x01a52994 in ServerLoop () at postmaster.c:1274
    port = (Port *) 0x22407400
    i = 2
    rmask = {__fds_bits = {32, 0 <repeats 31 times>}}
    selres = 1
    readmask = {__fds_bits = {56, 0 <repeats 31 times>}}
    nSockets = 6
    now = 1232972501
    last_touch_time = 1232970945
    __func__ = "ServerLoop"
#26 0x01a52198 in PostmasterMain (argc=3, argv=0x7fffddb4) at
postmaster.c:1029
    opt = -1
    status = 0
    userDoption = 0x7fffde77 "/usr/local/pgsql/data"
    i = 64
    __func__ = "PostmasterMain"
#27 0x019ce288 in main (argc=3, argv=0x7fffddb4) at main.c:188
No locals.
____

The SQL query is not necessarily the same each time this happens.

PostgreSQL was compiled using the FreeBSD "ports" system with GCC 4.2.1.

I'm assuming that this is a run-time bug and couldn't be triggered by a bad
database...?