UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Steps to reproduce the problem:
I haven't been able to reproduce the problem reliably.

What is the expected behavior?
No SEGV_MAPERR

What went wrong?
There appears to be a bad memory access inside of NetLog::AddEntry() according to the stack trace.

chrome_1              | Received signal 11 SEGV_MAPERR ffffff34556161d5
chrome_1              | #0 0x55e98d2e31ac base::debug::StackTrace::StackTrace()
chrome_1              | #1 0x55e98d2e2d11 base::debug::(anonymous namespace)::StackDumpSignalHandler()
chrome_1              | #2 0x7f61dab3f330 <unknown>
chrome_1              | #3 0x55e98d8f7b53 net::NetLog::AddEntry()
chrome_1              | #4 0x55e98d8f8a8e net::NetLogWithSource::AddEntry()
chrome_1              | #5 0x55e98d98df8a net::HostResolverImpl::ProcTask::OnLookupComplete()
chrome_1              | #6 0x55e98d2e451f base::debug::TaskAnnotator::RunTask()
chrome_1              | #7 0x55e98d2fe297 base::MessageLoop::RunTask()
chrome_1              | #8 0x55e98d2fe767 base::MessageLoop::DoWork()
chrome_1              | #9 0x55e98d3013e9 base::MessagePumpLibevent::Run()
chrome_1              | #10 0x55e98d320d05 base::RunLoop::Run()
chrome_1              | #11 0x55e98c02fbc8 content::BrowserThreadImpl::IOThreadRun()
chrome_1              | #12 0x55e98c02fd41 content::BrowserThreadImpl::Run()
chrome_1              | #13 0x55e98d34bfbd base::Thread::ThreadMain()
chrome_1              | #14 0x55e98d34a1dd base::(anonymous namespace)::ThreadFunc()
chrome_1              | #15 0x7f61dab37184 start_thread
chrome_1              | #16 0x7f61d4f9203d clone
chrome_1              |   r8: 000000c905fc9d28  r9: 00007f61cd8284b0 r10: 0013b7c19c0da0bb r11: 0000000000000246
chrome_1              |  r12: 00007f61cd828260 r13: 0000000900000001 r14: ffffff34556161cd r15: 00007f61cd828238
chrome_1              |   di: 0000000000000000  si: 000000008baa0b60  bp: 00007f61cd8282a0  bx: 000000c905b92780
chrome_1              |   dx: 0000000000000060  ax: 0000000000000000  cx: 0000000000000050  sp: 00007f61cd828230
chrome_1              |   ip: 000055e98d8f7b53 efl: 0000000000010212 cgf: 002b000000000033 erf: 0000000000000005
chrome_1              |  trp: 000000000000000e msk: 0000000000000000 cr2: ffffff34556161d5
chrome_1              | [end of stack trace]
chrome_1              | Calling _exit(1). Core file will not be generated.

Did this work before? N/A 

Chrome version: 66.0.3358.0  Channel: n/a
OS Version: ubuntu:14.04
Flash Version: