firefox 58.0 "Gah. Your tab just crashed"

[Havard Eidnes <he%NetBSD.org@localhost>]

Hi,

those of you running firefox 58.0 will in all probabilities have
seen the same message I'm seeing all too often: "Gah. Your tab
just crashed".  I'm not alone, right?

This *appears* to be an intermittent thing, but looking a bit
closer it does indeed seem like firefox is dumping core in these
cases, and that it hits a SEGV:

% ls -l firefox.core 
-rw-------  1 he  he  11281736 Feb  2 09:31 firefox.core
% gdb -q /usr/pkg/lib/firefox/firefox firefox.core 
Reading symbols from /usr/pkg/lib/firefox/firefox...(no debugging symbols found)...done.
[New process 1]
[New process 12]
[New process 11]
[New process 10]
[New process 9]
[New process 8]
[New process 7]
[New process 6]
[New process 5]
[New process 4]
[New process 3]
[New process 2]
Core was generated by `firefox'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000747806f7218c in ?? () from /usr/pkg/lib/firefox/libxul.so
[Current thread is 1 (LWP 1)]
(gdb) where
#0  0x0000747806f7218c in ?? () from /usr/pkg/lib/firefox/libxul.so
#1  0x0000747806f5a6d3 in ?? () from /usr/pkg/lib/firefox/libxul.so
#2  0x00007478085b1ebf in ?? () from /usr/pkg/lib/firefox/libxul.so
#3  0x000074780699c56e in ?? () from /usr/pkg/lib/firefox/libxul.so
#4  0x000074780699cc4d in ?? () from /usr/pkg/lib/firefox/libxul.so
#5  0x000074780699d1a0 in ?? () from /usr/pkg/lib/firefox/libxul.so
#6  0x000074780699d3c3 in ?? () from /usr/pkg/lib/firefox/libxul.so
#7  0x000074780695c2ee in ?? () from /usr/pkg/lib/firefox/libxul.so
#8  0x000074780699deef in ?? () from /usr/pkg/lib/firefox/libxul.so
#9  0x000074780699e6ed in ?? () from /usr/pkg/lib/firefox/libxul.so
#10 0x00007478069a0729 in ?? () from /usr/pkg/lib/firefox/libxul.so
#11 0x00007478069a1320 in ?? () from /usr/pkg/lib/firefox/libxul.so
#12 0x00007478069a1b41 in ?? () from /usr/pkg/lib/firefox/libxul.so
#13 0x00007478069a10e6 in ?? () from /usr/pkg/lib/firefox/libxul.so
#14 0x00007478069a1320 in ?? () from /usr/pkg/lib/firefox/libxul.so
#15 0x00007478069a1678 in ?? () from /usr/pkg/lib/firefox/libxul.so
#16 0x00007478069a1ad8 in ?? () from /usr/pkg/lib/firefox/libxul.so
#17 0x00007478069c53c8 in ?? () from /usr/pkg/lib/firefox/libxul.so
#18 0x0000747808b6283c in ?? () from /usr/pkg/lib/firefox/libxul.so
#19 0x0000747806bd6bca in ?? () from /usr/pkg/lib/firefox/libxul.so
#20 0x0000747807f51ed9 in ?? () from /usr/pkg/lib/firefox/libxul.so
#21 0x0000747808b62da5 in ?? () from /usr/pkg/lib/firefox/libxul.so
#22 0x0000000007605ad9 in _start ()
(gdb) i regi
rax            0x78213e0        125965280
rbx            0x747818352000   128059151032320
rcx            0x74780a142248   128058913989192
rdx            0x747819e83800   128059179546624
rsi            0x747819e83800   128059179546624
rdi            0x747819341a00   128059167742464
rbp            0x7f7fff28e338   0x7f7fff28e338
rsp            0x7f7fff28e2a0   0x7f7fff28e2a0
r8             0x0      0
r9             0x1      1
r10            0x0      0
r11            0x246    582
r12            0x7478193fba60   128059168504416
r13            0x7f7fff28e3a8   140187718443944
r14            0x0      0
r15            0x74780a08b860   128058913241184
rip            0x747806f7218c   0x747806f7218c
eflags         0x10246  [ PF ZF IF RF ]
cs             0x47     71
ss             0x3f     63
ds             0x3f     63
es             0x3f     63
fs             0x0      0
gs             0x0      0
(gdb) x/i 0x747806f7218c
=> 0x747806f7218c:      movl   $0x88,0x0
(gdb)

% file /usr/pkg/lib/firefox/libxul.so
/usr/pkg/lib/firefox/libxul.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=66b64c8f36f87456217e130d2f2c35feb80c6196, for NetBSD 8.0, stripped
%

Now, the usefulness of this information is probably questionable,
since the libul.so library doesn't appear to have any symbols
(how's that even possible for a shared library?!?)

However, if I read the disassembly correct, this instruction will
always (try to) store to address zero...

This is on amd64/8.0_BETA.  Anyone have any hints how to build
the package with debug support (or at least symbols?), and what
it takes in terms of resources to accomplish that?

Best regards,

- Håvard