Pcbnew segfaults when attempting to route differential pair with inconsistent naming

[Jeppe Johansen]

Trying to route a differential pair with incorrect net names will make pcbnew crash immediately.

Naming a net "A+" and trying to route it as a differential pair or do length matching will make it crash.

[Blair Bonnett (bcb)]

Can confirm on r5473. The attached PCB displays this behaviour. If you try to diff-pair route GND, then it pops up a dialog box telling you it isn't a differential pair. But if you click on USBD+, for which their is no corresponding USBD-, you get a segfault:

Program received signal SIGSEGV, Segmentation fault.
0x00007fffea8517d4 in PNS_DIFF_PAIR_PLACER::findDpPrimitivePair (this=this@entry=0x1f23b00, aP=..., aItem=aItem@entry=0x20c4800, aPair=...)
    at /home/blair/sources/kicad/product/pcbnew/router/pns_diff_pair_placer.cpp:494
494 refNet = netP;

(gdb) bt

#0 0x00007fffea8517d4 in PNS_DIFF_PAIR_PLACER::findDpPrimitivePair (this=this@entry=0x1f23b00, aP=..., aItem=aItem@entry=0x20c4800, aPair=...)
    at /home/blair/sources/kicad/product/pcbnew/router/pns_diff_pair_placer.cpp:494

#1 0x00007fffea85348a in PNS_DIFF_PAIR_PLACER::Start (this=0x1f23b00, aP=..., aStartItem=0x20c4800) at /home/blair/sources/kicad/product/pcbnew/router/pns_diff_pair_placer.cpp:573

#2 0x00007fffea83daca in PNS_ROUTER::StartRouting (this=0x1db2a60, aP=..., aStartItem=0x20c4800, aLayer=aLayer@entry=0) at /home/blair/sources/kicad/product/pcbnew/router/pns_router.cpp:528

#3 0x00007fffea82fd94 in ROUTER_TOOL::prepareInteractive (this=this@entry=0x2c66c70) at /home/blair/sources/kicad/product/pcbnew/router/router_tool.cpp:453

#4 0x00007fffea83365c in ROUTER_TOOL::performRouting (this=this@entry=0x2c66c70) at /home/blair/sources/kicad/product/pcbnew/router/router_tool.cpp:494

#5 0x00007fffea83481f in ROUTER_TOOL::mainLoop (this=this@entry=0x2c66c70, aMode=aMode@entry=PNS_MODE_ROUTE_DIFF_PAIR) at /home/blair/sources/kicad/product/pcbnew/router/router_tool.cpp:645

#6 0x00007fffea834e48 in ROUTER_TOOL::RouteDiffPair (this=0x2c66c70, aEvent=...) at /home/blair/sources/kicad/product/pcbnew/router/router_tool.cpp:601

#7 0x00007fffea977bc1 in operator() (aA=..., this=0x20c4890) at /home/blair/sources/kicad/product/include/tool/delegate.h:58

#8 COROUTINE<int, TOOL_EVENT const&>::callerStub (aData=34359440) at /home/blair/sources/kicad/product/include/tool/coroutine.h:214
#9 0x00007fffe8008731 in make_fcontext () from /usr/lib/libboost_context.so.1.57.0
#10 0x0000000000000000 in ?? ()

-----------------------------------------------------------------------

Application: pcbnew
Version: (2015-03-04 BZR 5473)-product Debug build
wxWidgets: Version 3.0.2 (debug,wchar_t,compiler with C++ ABI 1002,GCC 4.9.2,wx containers,compatible with 2.8)
Platform: Linux 3.18.6-1-ARCH x86_64, 64 bit, Little endian, wxGTK
Boost version: 1.57.0
         USE_WX_GRAPHICS_CONTEXT=OFF
         USE_WX_OVERLAY=OFF
         KICAD_SCRIPTING=ON
         KICAD_SCRIPTING_MODULES=ON
         KICAD_SCRIPTING_WXPYTHON=ON
         USE_FP_LIB_TABLE=HARD_CODED_ON
         BUILD_GITHUB_PLUGIN=ON
         KICAD_USE_WEBKIT=ON

[Nick Østergaard (nickoe)]

Segfaults should be critical.

[Nick Østergaard (nickoe)]

I can also confirm this issue. I get the same backtrace. Note that you have to try to trace form the one with the "+" for example. I had a "c+" and a "c" pin, and it will detect fine that "c" is not a diff pair.