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IDProjectCategoryView StatusDate SubmittedLast Update
0001483graphvizDotpublic2008-11-17 20:482011-04-28 04:03
ReporterJosep M. Perez 
Assigned Togviz 
PlatformOS*-*-OS Version
Summary0001483: Segmentation fault in make_regular_edge() in dotsplines.c:1448

Running the following command causes a segfault in dot:

dot -Tps -v -Gnslimit=0.1

I've recompiled the Debian package without optimization and with
debugging turned on. Gdb gives the following backtrace:
#0 0xb7ce0c33 in make_regular_edge (sp=0xbfddc094, P=0x9777b30, edges=0x8c1f4c8, ind=3505, cnt=1, et=8) at dotsplines.c:1448
0000001 0xb7cdcba2 in _dot_splines (g=0x88e68a8, normalize=1) at dotsplines.c:396
0000002 0xb7cdcdac in dot_splines (g=0x88e68a8) at dotsplines.c:448
0000003 0xb7cd25ce in dot_layout (g=0x88e68a8) at dotinit.c:212
0000004 0xb7f366dd in gvLayoutJobs (gvc=0x88d97b0, g=0x88e68a8) at gvlayout.c:69
0000005 0x08048a3f in main (argc=5, argv=0xbfddc384) at dot.c:180

Running the command inside valgrind causes a read error:

==9030== Invalid read of size 4
==9030== at 0x46D9C33: make_regular_edge (dotsplines.c:1448)
==9030== by 0x46D5BA1: _dot_splines (dotsplines.c:396)
==9030== by 0x46D5DAB: dot_splines (dotsplines.c:448)
==9030== by 0x46CB5CD: dot_layout (dotinit.c:212)
==9030== by 0x405D6DC: gvLayoutJobs (gvlayout.c:69)
==9030== by 0x8048A3E: main (dot.c:180)
==9030== Address 0x36c is not stack'd, malloc'd or (recently) free'd

The relevant code lines are:

1447 for (i = 0; i < pn; i++)
1448 points[pointn++] = ps[i];

At the time it crashes ps=0x318, pointn=1153 and i=10. Looks like the
points array is not big enough and is overlapping the memory used for
storing the address of ps:

(gdb) print &ps
$3 = (point **) 0xbeb06128
(gdb) print &points[pointn-1]
$4 = (point *) 0xbeb06124

BTW, sizeof(point)=8, so the previous iteration actually overwrites the
ps variable.
Additional Information
Reported via Debian: [email protected]

[gordon.smith] I just found a similar one in Windows (I compile all of dot into a single
DLL called "libagraph")....

Looks like the abort call is a bit "aggressive"?

\<A HREF=""\>Dot file\</A\> is attached.

Stack Trace:
> > msvcr90d.dll!_NMSG_WRITE(int rterrnum=10) Line 198 C
     msvcr90d.dll!abort() Line 59 + 0x7 bytes C
     libagraph.dll!triangulate(pointnlink_t * * pnlps=0x08b70438, int
pnln=14) Line 310 + 0x8 bytes C
     libagraph.dll!triangulate(pointnlink_t * * pnlps=0x08b70438, int
pnln=15) Line 306 + 0x10 bytes C
     libagraph.dll!triangulate(pointnlink_t * * pnlps=0x08b70438, int
pnln=16) Line 306 + 0x10 bytes C
     libagraph.dll!Pshortestpath(Ppoly_t * polyp=0x073fcad0, Pxy_t *
eps=0x073fca7c, Ppoly_t * output=0x073fcac0) Line 166 + 0x12 bytes C
     libagraph.dll!_routesplines(path * pp=0x0a0d94f8, int *
npoints=0x073fcdac, int polyline=0) Line 421 + 0x11 bytes C
     libagraph.dll!routesplines(path * pp=0x0a0d94f8, int *
npoints=0x073fcdac) Line 533 + 0xf bytes C
     libagraph.dll!make_flat_labeled_edge(spline_info_t * sp=0x073fdd40,
path * P=0x0a0d94f8, Agedge_t * e=0x09fb1b38, int et=8) Line 1072 + 0x16
bytes C
     libagraph.dll!make_flat_edge(spline_info_t * sp=0x073fdd40, path *
P=0x0a0d94f8, Agedge_t * * edges=0x0b0a70d0, int ind=0, int cnt=1, int et=8)
Line 1183 + 0x18 bytes C
     libagraph.dll!_dot_splines(Agraph_t * g=0x03922ed8, int normalize=1)
Line 388 + 0x29 bytes C
     libagraph.dll!dot_splines(Agraph_t * g=0x03922ed8) Line 452 + 0xb
bytes C
     libagraph.dll!dot_layout(Agraph_t * g=0x03922ed8) Line 273 + 0x9
bytes C
     libagraph.dll!gvLayoutJobs(GVC_s * gvc=0x08bc2fb8, Agraph_t *
g=0x03922ed8) Line 87 + 0xd bytes C
     libagraph.dll!gvLayout(GVC_s * gvc=0x08bc2fb8, Agraph_t *
g=0x03922ed8, const char * engine=0x06b5eecc) Line 71 + 0xd bytes C
     libagraph.dll!DoLayout(const char * layout=0x06b5eecc, const char *
mem=0x09eef440, const char * out=0x03961c88, const char * format=0x073febf8,
const char * scale=0x073fefb0) Line 88 + 0x14 bytes C++

TagsNo tags attached.
VERSION     2.20.3
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- Issue History
Date Modified Username Field Change
2011-04-28 04:03 user1 New Issue
2011-04-28 04:03 user1 Assigned To => user1

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