[ragel-users] Mandelbug causing segfault

Wed Dec 15 21:55:26 UTC 2010

Hi again,

On Tue, Dec 14, 2010 at 20:33, Mark Tsuchida <marktsuchida at gmail.com> wrote:
> Dear Adrian,
>
> Thank you for sharing this great tool.
>
> I am getting a segfault when running Ragel on my input file.
>
> Below is the simplest input file I've been able to create that
> triggers the segfault (sorry it's still rather complex).
> Whether or not Ragel crashes seems to be (depending on other parts of
> the input file) sometimes sensitive to the names given to actions (or
> at least the length of those names), among other things. Any given
> input file always gives the same result (segfault or no crash),
> though.
>
> Giving Ragel the -n or -m option appears to prevent the crash, at
> least with the input shown below.
>
> Both version 6.6 and the svn head (r1683) experience the same issue.
> I'm on Mac OS X 10.6 and Regal was compiled with g++ 4.2.1 (Xcode
> 3.2.5) (arch is x86_64 (LP64)).
>
> Please let me know if there is anything else I can provide to help
> track this down.
>
> Thanks,
> Mark
>
>
> $ cat test.rl
> %%{
> machine test;
>
> action action1 {}
> action action2 {}
>
> nl = ("\r\n" | [\n\r]);
> kw = "aaaaa";
> ident = "bbbbb" @action1;
> normal = (kw | ident);
>
> first = ([^\n\r] @action1)* . nl;
>
> cont = (
>    (" " @action1 when action1)* .
>    (((([^\n\r] @action1)*) . nl @action1) when action1)
> );
>
> special = first (cont when action2)** ;
>
> main := (normal when action1) | (special when action1);
>
> }%%
> $ ragel test.rl
> Segmentation fault
> $ ragel -V test.rl
> Segmentation fault
> $ ragel -T0 test.rl
> Segmentation fault
> $ ragel -T1 test.rl
> Segmentation fault
> $ ragel -F0 test.rl
> Segmentation fault
> $ ragel -F1 test.rl
> Segmentation fault
> $ ragel -d test.rl
> Segmentation fault
> $ ragel -e test.rl
> Segmentation fault
> $ ragel -n test.rl  # succeeds
> $ ragel -m test.rl  # succeeds
> $
>

Here is a stack trace from the svn head version (trunk @ r1683):

(gdb) run test.rl
Starting program: /Users/mark/devel/ragel/trunk/ragel/ragel test.rl
Reading symbols for shared libraries ++. done

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000048
0x00000001000161fb in NextTrans<TransAp>::load (this=0x7fff5fbfd788)
at fsmgraph.h:782
782                             next = trans->next;
(gdb) where
#0  0x00000001000161fb in NextTrans<TransAp>::load
(this=0x7fff5fbfd788) at fsmgraph.h:782
#1  0x0000000100016255 in NextTrans<TransAp>::set
(this=0x7fff5fbfd788, t=0x20) at fsmgraph.h:790
#2  0x0000000100025612 in PairIter<TransAp, StateCond>::findNext
(this=0x7fff5fbfd770) at fsmgraph.h:901
#3  0x0000000100025dab in PairIter<TransAp, StateCond>::PairIter
(this=0x7fff5fbfd770, list1=0x20, list2=0x10030c700) at fsmgraph.h:854
#4  0x000000010002050a in FsmAp::findEmbedExpansions
(this=0x1003085d0, expansionList=@0x7fff5fbfd9e0,
destState=0x100309900, condAction=0x100301b60, sense=true) at
fsmgraph.cpp:1298
#5  0x0000000100021b28 in FsmAp::embedCondition (this=0x1003085d0,
md=@0x7fff5fbfda50, state=0x100309900, condAction=0x100301b60,
sense=true) at fsmgraph.cpp:1403
#6  0x00000001000222f5 in FsmAp::embedCondition (this=0x1003085d0,
state=0x100309900, condAction=0x100301b60, sense=true) at
fsmgraph.cpp:1389
#7  0x0000000100029e3a in FsmAp::allTransCondition (this=0x1003085d0,
condAction=0x100301b60, sense=true) at fsmap.cpp:872
#8  0x000000010000555a in FactorWithAug::assignConditions
(this=0x100305f20, graph=0x1003085d0) at parsetree.cpp:1176
#9  0x0000000100008f34 in FactorWithAug::walk (this=0x100305f20,
pd=0x1003006e0) at parsetree.cpp:1226
#10 0x0000000100009660 in Term::walk (this=0x100306010,
pd=0x1003006e0, lastInSeq=true) at parsetree.cpp:948
#11 0x000000010000986b in Expression::walk (this=0x100306040,
pd=0x1003006e0, lastInSeq=true) at parsetree.cpp:782
#12 0x0000000100009a75 in Join::walk (this=0x100306070,
pd=0x1003006e0) at parsetree.cpp:598
#13 0x0000000100008139 in Factor::walk (this=0x1003060a0,
pd=0x1003006e0) at parsetree.cpp:1790
#14 0x0000000100008226 in FactorWithNeg::walk (this=0x100306100,
pd=0x1003006e0) at parsetree.cpp:1710
#15 0x0000000100008c74 in FactorWithRep::walk (this=0x100306130,
pd=0x1003006e0) at parsetree.cpp:1624
#16 0x0000000100008e1e in FactorWithAug::walk (this=0x100306180,
pd=0x1003006e0) at parsetree.cpp:1212
#17 0x0000000100009660 in Term::walk (this=0x100306210,
pd=0x1003006e0, lastInSeq=true) at parsetree.cpp:948
#18 0x000000010000970b in Expression::walk (this=0x100306240,
pd=0x1003006e0, lastInSeq=true) at parsetree.cpp:738
#19 0x0000000100009a75 in Join::walk (this=0x100306270,
pd=0x1003006e0) at parsetree.cpp:598
#20 0x0000000100009c94 in MachineDef::walk (this=0x1003062a0,
pd=0x1003006e0) at parsetree.cpp:533
#21 0x0000000100007f33 in VarDef::walk (this=0x100306320,
pd=0x1003006e0) at parsetree.cpp:94
#22 0x000000010000d639 in ParseData::makeInstance (this=0x1003006e0,
gdNode=0x1003062c0) at parsedata.cpp:1062
#23 0x000000010000f648 in ParseData::makeAll (this=0x1003006e0) at
parsedata.cpp:1189
#24 0x0000000100010f4d in ParseData::prepareMachineGenTBWrapped
(this=0x1003006e0, graphDictEl=0x0) at parsedata.cpp:1396
#25 0x0000000100011040 in ParseData::prepareMachineGen
(this=0x1003006e0, graphDictEl=0x0) at parsedata.cpp:1369
#26 0x0000000100048d76 in InputData::prepareMachineGen
(this=0x7fff5fbfe750) at inputdata.cpp:191
#27 0x0000000100001e33 in process (id=@0x7fff5fbfe750) at main.cpp:478
#28 0x00000001000029b2 in main (argc=2, argv=0x7fff5fbfe820) at main.cpp:559
(gdb)

Mark

_______________________________________________
ragel-users mailing list
ragel-users at complang.org
http://www.complang.org/mailman/listinfo/ragel-users