firefox -headless segfaults
Very easy to reproduce:
$ docker run --rm alpine:edge sh -c 'apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing firefox strace && strace firefox -headless' 2>&1 | tail
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x98} ---
unlink("/root/.mozilla/firefox/apgg61bn.default-default/lock") = 0
close(4) = 0
rt_sigaction(SIGSEGV, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER, sa_restorer=0x7f8383102aaf}, NULL, 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [SEGV], NULL, 8) = 0
rt_sigprocmask(SIG_BLOCK, ~[RTMIN RT_1 RT_2], [], 8) = 0
tkill(26, SIGSEGV) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
--- SIGSEGV {si_signo=SIGSEGV, si_code=SI_TKILL, si_pid=26, si_uid=0} ---
+++ killed by SIGSEGV (core dumped) +++