Cyclotron out of range field lookup
Summary
The magnetic field lookup can be out of range resulting in an segmentation fault.
Steps to reproduce
One way to reproduce this is to have a trim coil with a very large BMAX
, e.g.:
tc15: TRIMCOIL, TYPE="PSI-PHASE", RMIN = 3000, RMAX = 4560.073, BMAX=100.0025264327051118017, COEFNUM = {-0.0312020990404, 0.0227946756108, -0.00354827255973}, COEFDENOM = {14.7460286849, -16.9186605846, 7.61516943548, -1.53074181639, 0.11384470123};
psi_ring: Cyclotron, TYPE="RING", CYHARMON=6, PHIINIT=0.0, PRINIT=pr0, RINIT=r0 , SYMMETRY=8.0, RFFREQ=frequency, FMAPFN="./s03av.nar", FMLOWE=0.072, FMHIGHE=0.595,
TRIMCOIL={tc15};
What is the current bug behavior?
segmentation fault:
OPAL> * ---------------------- Start tracking ---------------------------------- *
/afs/psi.ch/sys/psi.x86_64_slp6/Programming/gcc/10.3.0/include/c++/10.3.0/bits/stl_vector.h:1045: std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](std::vector<_Tp, _Alloc>::size_type) [with _Tp = double; _Alloc = std::allocator<double>; std::vector<_Tp, _Alloc>::reference = double&; std::vector<_Tp, _Alloc>::size_type = long unsigned int]: Assertion '__builtin_expect(__n < this->size(), true)' failed.
Thread 1 "opal" received signal SIGABRT, Aborted.
0x00007ffff43a2aff in raise () from /lib64/libc.so.6
Missing separate debuginfos, use: yum debuginfo-install bzip2-libs-1.0.6-26.el8.x86_64 glibc-2.28-211.el8.x86_64 zlib-1.2.11-21.el8_7.x86_64
(gdb) bt
#0 0x00007ffff43a2aff in raise () from /lib64/libc.so.6
#1 0x00007ffff4375ea5 in abort () from /lib64/libc.so.6
#2 0x00000000004c60c2 in std::__replacement_assert (
__file=__file@entry=0xce5908 "/afs/psi.ch/sys/psi.x86_64_slp6/Programming/gcc/10.3.0/include/c++/10.3.0/bits/stl_vector.h", __line=__line@entry=1045,
__function=__function@entry=0xce77d8 "std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](std::vector<_Tp, _Alloc>::size_type) [with _Tp = double; _Alloc = std::allocator<double>; std::vector<_Tp, _Alloc>::reference ="..., __condition=__condition@entry=0xce5e98 "__builtin_expect(__n < this->size(), true)")
at /afs/psi.ch/sys/psi.x86_64_slp6/Programming/gcc/10.3.0/include/c++/10.3.0/x86_64-pc-linux-gnu/bits/c++config.h:461
#3 0x00000000007785c0 in std::vector<double, std::allocator<double> >::operator[] (__n=19210, this=0x1999428)
at /home/snuverink_j/OPAL/src/src/Classic/AbsBeamline/Cyclotron.cpp:767
#4 Cyclotron::interpolate (this=this@entry=0x1998fd0, rad=@0x7fffffff6ac8: 4.7088452431449133,
tet_rad=@0x7fffffff6ad0: 0.1981665351710836, brint=@0x7fffffff6ad8: 0, btint=@0x7fffffff6ae0: 0,
bzint=@0x7fffffff6ae8: 0) at /home/snuverink_j/OPAL/src/src/Classic/AbsBeamline/Cyclotron.cpp:750
#5 0x000000000077887b in Cyclotron::apply (this=0x1998fd0, R=..., t=@0x7fffffff6f38: 6000.00000001014, E=..., B=...)
at /home/snuverink_j/OPAL/src/src/Classic/AbsBeamline/Cyclotron.cpp:454
#6 0x0000000000775b38 in Cyclotron::apply (this=0x1998fd0, id=@0x7fffffff70d8: 1, t=@0x7fffffff6f38: 6000.00000001014,
E=..., B=...) at /home/snuverink_j/OPAL/src/src/Classic/AbsBeamline/Cyclotron.cpp:409
#7 0x00000000006d2154 in ParallelCyclotronTracker::computeExternalFields_m (this=this@entry=0x1996380,
i=@0x7fffffff70d8: 1, t=<optimized out>, Efield=..., Bfield=...)
at /home/snuverink_j/OPAL/src/src/Algorithms/ParallelCyclotronTracker.cpp:3417
#8 0x00000000006d21bf in ParallelCyclotronTracker::getFieldsAtPoint (this=0x1996380, t=<optimized out>,
Pindex=@0x7fffffff70d8: 1, Efield=..., Bfield=...)
at /home/snuverink_j/OPAL/src/src/Algorithms/ParallelCyclotronTracker.cpp:1463
#9 0x00000000006ebe66 in std::function<bool (double const&, unsigned long const&, Vektor<double, 3u>&, Vektor<double, 3u>&)>::operator()(double const&, unsigned long const&, Vektor<double, 3u>&, Vektor<double, 3u>&) const (__args#3=...,
__args#2=..., __args#1=@0x7fffffff70d8: 1, __args#0=@0x7fffffff6da8: 6.9533465388994597e-310, this=<optimized out>)
at /afs/psi.ch/sys/psi.x86_64_slp6/Programming/gcc/10.3.0/include/c++/10.3.0/bits/std_function.h:248
#10 RK4<std::function<bool (double const&, unsigned long const&, Vektor<double, 3u>&, Vektor<double, 3u>&)>>::derivate_m(PartBunchBase<double, 3u>*, double*, double const&, double*, unsigned long const&) const (this=this@entry=0x193f8f0,
bunch=bunch@entry=0x193c500, y=y@entry=0x7fffffff7030, t=@0x7fffffff6f38: 6000.00000001014,
yp=yp@entry=0x7fffffff7000, i=@0x7fffffff70d8: 1) at /home/snuverink_j/OPAL/src/src/Steppers/RK4.hpp:108
#11 0x00000000006ec366 in RK4<std::function<bool (double const&, unsigned long const&, Vektor<double, 3u>&, Vektor<double, 3u>&)>>::doAdvance_m(PartBunchBase<double, 3u>*, unsigned long const&, double const&, double) const (this=0x193f8f0,
bunch=0x193c500, i=@0x7fffffff70d8: 1, t=@0x7fffffff7168: 5999.9341888880599, dt=0.065811122079631468)
at /home/snuverink_j/OPAL/src/src/Steppers/RK4.hpp:70
#12 0x00000000006d2a51 in Stepper<std::function<bool (double const&, unsigned long const&, Vektor<double, 3u>&, Vektor<double, 3u>&)>>::advance(PartBunchBase<double, 3u>*, unsigned long const&, double const&, double) const (
dt=0.065811122079631468, t=@0x7fffffff7168: 5999.9341888880599, i=@0x7fffffff70d8: 1, bunch=0x193c500,
this=<optimized out>) at /home/snuverink_j/OPAL/src/src/Algorithms/ParallelCyclotronTracker.cpp:3046
#13 ParallelCyclotronTracker::seoMode_m (this=this@entry=0x1996380, t=@0x7fffffff7168: 5999.9341888880599,
dt=0.065811122079631468, Ttime=..., Tdeltr=..., Tdeltz=..., TturnNumber=...)
at /home/snuverink_j/OPAL/src/src/Algorithms/ParallelCyclotronTracker.cpp:3046
#14 0x00000000006e21dd in ParallelCyclotronTracker::GenericTracker (this=0x1996380)
at /home/snuverink_j/OPAL/src/src/Algorithms/ParallelCyclotronTracker.cpp:1429
#15 0x00000000006e2765 in ParallelCyclotronTracker::execute (this=0x1996380)
at /home/snuverink_j/OPAL/src/src/Algorithms/ParallelCyclotronTracker.cpp:1238
#16 0x00000000006b2651 in TrackRun::execute (this=0x193e6c0) at /home/snuverink_j/OPAL/src/src/Track/TrackRun.cpp:245
#17 0x000000000053531b in OpalParser::execute (this=this@entry=0x193bb50, object=object@entry=0x193e6c0, name=...)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:140
#18 0x0000000000538d29 in OpalParser::parseAction (this=0x193bb50, stat=...)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:173
#19 0x00000000005392d9 in OpalParser::parse (this=0x193bb50, stat=...)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:91
#20 0x00000000005390d6 in OpalParser::run (this=0x193bb50)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:608
#21 0x00000000006aaba9 in TrackCmd::execute (this=0x18947b0) at /home/snuverink_j/OPAL/src/src/Track/TrackCmd.cpp:230
#22 0x000000000053531b in OpalParser::execute (this=this@entry=0x7fffffff8490, object=object@entry=0x18947b0, name=...)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:140
#23 0x0000000000538d29 in OpalParser::parseAction (this=0x7fffffff8490, stat=...)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:173
#24 0x00000000005392d9 in OpalParser::parse (this=0x7fffffff8490, stat=...)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:91
#25 0x00000000005390d6 in OpalParser::run (this=0x7fffffff8490)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:608
#26 0x0000000000535800 in OpalParser::run (this=this@entry=0x7fffffff8490, is=is@entry=0x1890ad0)
at /home/snuverink_j/OPAL/src/src/OpalParser/OpalParser.cpp:633
#27 0x00000000004b3843 in opalMain (argc=<optimized out>, argv=<optimized out>)
at /home/snuverink_j/OPAL/src/src/Main.cpp:364
#28 0x00007ffff438ed85 in __libc_start_main () from /lib64/libc.so.6
#29 0x00000000004af24e in _start () at /home/snuverink_j/OPAL/src/src/Main.cpp:131
What is the expected correct behavior?
not crash and ignore the field. the particle will be cleaned up afterwards.
Possible fixes
https://gitlab.psi.ch/OPAL/src/-/blob/master/src/Classic/AbsBeamline/Cyclotron.cpp#L747:
if (fieldType_m != BFieldType::FFABF) {
/*
For FFA this does not work
*/
r1t1 = it + ntetS * ir - 1;
r1t2 = r1t1 + 1;
r2t1 = r1t1 + ntetS;
r2t2 = r2t1 + 1 ;
} else {
/*
With this we have B-field AND this is far more
intuitive for me ....
*/
r1t1 = idx(ir, it);
r2t1 = idx(ir + 1, it);
r1t2 = idx(ir, it + 1);
r2t2 = idx(ir + 1, it + 1);
}
if ((it >= 0) && (ir >= 0) && (it < Bfield_m.ntetS_m) && (ir < Bfield_m.nrad_m)) {
// lookup and apply field
The range check should rather be ir + 1 < Bfield_m.nrad_m