Odd crash on Linux and Windows XP (on all versions of the compiler)

[ziggi]

Sometimes i got crash on 2078 line in sc3.c:

        if (arg[argidx].numtags==1)     /* set the expected tag, if any */
          lval.cmptag=arg[argidx].tags[0]; // crash here

I can't show small Pawn code for reproduce this, because It is not always. Sometimes i change one symbol and get compiler crash, after it I change false on true in strcmp and fix it -_-.

On Windows 7 everything is always good.

Without these lines at first sight everything works good.

[Zeex]

Can you show the output of info locals and info args commands in gdb at the point of the crash?

[ziggi]

Pawn compiler 3.10.20150503                     Copyright (c) 1997-2006, ITB CompuPhase


Program received signal SIGSEGV, Segmentation fault.
0x00007ffff799a7db in callfunction (sym=0x6eb400, lval_result=0x7fffffffdde0, 
    matchparanthesis=1) at /home/ziggi/dev/samp/development/pawn/source/compiler/sc3.c:2078
2078              lval.cmptag=arg[argidx].tags[0];

(gdb) info locals
nest_stkusage = 0
nesting = 1
locheap = 0
close = 0
lvalue = 32767
argpos = 0
argidx = 0
nargs = 0
heapalloc = 0
namedparams = 0
lval = {sym = 0x0, constval = 0, tag = 0, cmptag = 0, ident = 0 '\000', 
  boolresult = 0 '\000', arrayidx = 0x0}
arg = 0x6eaef0
arglist = "\002", '\000' <repeats 125 times>
arrayszlst = {next = 0x0, name = '\000' <repeats 31 times>, value = 0, index = 0}
taglst = {next = 0x0, name = '\000' <repeats 31 times>, value = 0, index = 0}
symret = 0x0
lexval = 32767
lexstr = 0x7ffff7bbc589 <pline+9> "_OnPlayerStateChange(playerid, newstate, oldstate);\r\n"
__PRETTY_FUNCTION__ = "callfunction"

(gdb) info args
sym = 0x6eb400
lval_result = 0x7fffffffdde0
matchparanthesis = 1

[ziggi]

Maybe it will be useful too:

(gdb) p arg[argidx]
$16 = {
  name = "\000\000\000\000\000\000\000\000X\234\226\367\377\177", '\000' <repeats 17 times>, 
  ident = 0 '\000', usage = 83 'S', tags = 0x430755dd41757176, numtags = 1, dim = {1, 583, 
    -994609610}, idxtag = {-1031180662, 1096484389, 1124595925}, numdim = 1, 
  hasdefault = 1 '\001', defvalue = {val = -994852039, size = {
      symname = 0xc3322dbfc4b3c339 <error: Cannot access memory at address 0xc3322dbfc4b3c339>, level = -3355}, array = {data = 0xc3322dbfc4b3c339, size = 1096479461, 
      arraysize = 1135011142, addr = 1}}, defvalue_tag = 583}

(gdb) p arg[argidx].tags
$17 = (int *) 0x430755dd41757176
(gdb) p arg[argidx].tags[0]
Cannot access memory at address 0x430755dd41757176

[Zeex]

OK, thanks.

BTW it seems that you're using a 64-bit binary of the compiler instead of a 32-bit one. That may be not 100% working. To compile a 32-bit executable you need to pass a -DCMAKE_C_FLAGS=-m32 option to cmake.

[ziggi]

After change the compiler on a 32-bit version, gamemode was compiled good. But I made some changes (define FIXES_Single 1) and I got crash again:

Pawn compiler 3.10.25c7f33                      Copyright (c) 1997-2006, ITB CompuPhase


Program received signal SIGSEGV, Segmentation fault.
0xf7f5477f in callfunction (sym=0x80fb690, lval_result=0xffffcf94, matchparanthesis=1)
    at /home/ziggi/dev/samp/development/pawn/source/compiler/sc3.c:2078
2078              lval.cmptag=arg[argidx].tags[0];

(gdb) info locals
nest_stkusage = 0
nesting = 1
locheap = 0
close = 0
lvalue = 124
argpos = 0
argidx = 0
nargs = 0
heapalloc = 0
namedparams = 0
lval = {sym = 0x0, constval = 0, tag = 0, cmptag = 0, ident = 0 '\000', 
  boolresult = 0 '\000', arrayidx = 0x0}
arg = 0x80fb700
arglist = "\002", '\000' <repeats 125 times>
arrayszlst = {next = 0x0, name = '\000' <repeats 31 times>, value = 0, index = 0}
taglst = {next = 0x0, name = '\000' <repeats 31 times>, value = 0, index = 0}
symret = 0x0
lexval = 1
lexstr = 0x80 <error: Cannot access memory at address 0x80>
__PRETTY_FUNCTION__ = "callfunction"

(gdb) info args
sym = 0x80fb690
lval_result = 0xffffcf94
matchparanthesis = 1

(gdb) p arg[argidx]
$1 = {
  name = "p\330\362\367p\330\362\367\000\000\000\000\000\000\000\000\035\002\000\000i\376\265Da\355\063EO\036'A", ident = 0 '\000', usage = 21 '\025', tags = 0x33, numtags = 1, dim = {
    545, 1153380971, 1160985191}, idxtag = {1093278263, 1132856748, 39}, numdim = 1, 
  hasdefault = 165 '\245', defvalue = {val = 1153381418, size = {
      symname = 0x44bf342a <error: Cannot access memory at address 0x44bf342a>, 
      level = 15309}, array = {data = 0x44bf342a, size = 1160854477, arraysize = 1093288224, 
      addr = 1132918322}}, defvalue_tag = 62}

(gdb) p arg[argidx].tags
$2 = (int *) 0x33
(gdb) p arg[argidx].tags[0]
Cannot access memory at address 0x33

[Zeex]

This was fixed by #115.