#2398 SIGSEGV: DNS, memcpy

I was just preparing for a flight in MP, and FG crashed:

#0  0x00007ffff4be82a3 in memcpy@GLIBC_2.2.5 () from /usr/lib/libc.so.6
#1  0x00007ffff4fe9fee in std::char_traits<char>::copy (__n=<optimized out>, __s2=0x55556dbbd859 "mpserver13.flightgear.org", __s1=<optimized out>) at /build/gcc/src/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/char_traits.h:395
#2  std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy (__n=<optimized out>, __s=0x55556dbbd859 "mpserver13.flightgear.org", __d=<optimized out>) at /build/gcc/src/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.h:351
#3  std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy (__n=<optimized out>, __s=0x55556dbbd859 "mpserver13.flightgear.org", __d=<optimized out>) at /build/gcc/src/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.h:346
#4  std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_replace (this=0x5555599a9df0, __pos=<optimized out>, __len1=0, __s=0x55556dbbd859 "mpserver13.flightgear.org", __len2=<optimized out>) at /build/gcc/src/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.tcc:442
#5  0x00005555564b6cea in simgear::DNS::dnscbTXT(dns_ctx*, dns_rr_txt*, void*) ()
#6  0x00005555565c5500 in dns_ioevent ()
#7  0x0000555556554ddb in SGSubsystemGroup::Member::update(double) ()
#8  0x000055555655acaf in SGSubsystemGroup::update(double) ()
#9  0x0000555556550f5a in SGSubsystemMgr::update(double) ()
#10 0x00005555562dbb83 in fgMainLoop() ()
#11 0x0000555556252009 in fgOSMainLoop() ()
#12 0x00005555562df518 in fgMainInit(int, char**) ()
#13 0x0000555555b3549b in main ()

I was connected to mpserver01, not mpserver13, though.

Versions:

flightgear 96a6181be 2020-10-13 Update default catalog ID, URLs (origin/release/2020.2, release/2020.2) [Automatic Release Builder]
simgear bd9f04d9 2020-10-13 TerraSync: retry after socket failures (HEAD -> release/2020.2, origin/release/2020.2) [Automatic Release Builder]
fgdata e2df5ade6 2020-10-16 FG1000: GMC710 AFCS Mode controller. (origin/release/2020.2, release/2020.2) [Stuart Buchanan]
OpenSceneGraph d69f2a81f 2017-08-28 Updated ChangeLog for 3.4.1 release (HEAD, tag: OpenSceneGraph-3.4.1) [Robert Osfield]

[James Turner]

I've seen one crash like this on the crash-reproting system as well, but never any clear pattern of why, it's very strange. I guess it was a one-off crash, right?

[Anonymous]

Yes, so far. Maybe something bad gets into DNS results sometimes?

[Gijs]

Closing this for now, as there've been no further reports in the past four years. Please report back if you've encountered it with a more recent version of FlightGear.