I confirm this -- running 25.1+1-2 on amd64, I get the exact same backtrace:
Backtrace:
emacs[0x50b89c]
emacs[0x4f1c5c]
emacs[0x50a00e]
emacs[0x50a239]
emacs[0x50a29f]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x11100)[0x7f2b00e2b100]
emacs(re_search_2+0x3a8)[0x542908]
...
FWIW, both Emacs 25 and Emacs 26 compiled from source run fine on this
system.
