#0  0x00007fd2a788f3a8 in pkgPolicy::GetCandidateVer ()
   from /usr/lib/libapt-pkg-libc6.8-6.so.4.6
#1  0x00007fd2a786ec32 in pkgDepCache::Init ()
   from /usr/lib/libapt-pkg-libc6.8-6.so.4.6
#2  0x00007fd2a788d2eb in pkgCacheFile::Open ()
   from /usr/lib/libapt-pkg-libc6.8-6.so.4.6
#3  0x000000000040e7f9 in ?? ()
#4  0x00007fd2a785c6b5 in CommandLine::DispatchArg ()
   from /usr/lib/libapt-pkg-libc6.8-6.so.4.6
#5  0x000000000040a6b5 in ?? ()
#6  0x00007fd2a6b2d466 in __libc_start_main () from /lib/libc.so.6
#7  0x00000000004063e9 in ?? ()
#8  0x00007fffafd0bf48 in ?? ()
#9  0x000000000000001c in ?? ()
#10 0x0000000000000004 in ?? ()
#11 0x00007fffafd0cec0 in ?? ()
#12 0x00007fffafd0cec8 in ?? ()
#13 0x00007fffafd0cece in ?? ()
#14 0x00007fffafd0ced1 in ?? ()
#15 0x0000000000000000 in ?? ()