Comment 14 for bug 1376324

BTW, errors.ubuntu.com's idea of "StacktraceAddressSignature" looks like it could be subject to collisions. In the cases mentioned in comment #13, they're only grouped together because they all have crashes that are identical to depth 4:

#0 __libc_do_syscall () at ../ports/sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:44
No locals.
#1 0xb6808e5e in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
        _a1 = 0
        _a3tmp = 6
        _a1tmp = 0
        _a3 = 6
        _nametmp = 268
        _a2tmp = 2338
        _a2 = 2338
        _name = 268
        _sys_result = <optimized out>
        pd = 0xae2ff3d0
        pid = 0
        selftid = 2338
#2 0xb6809b4e in __GI_abort () at abort.c:89
        save_stage = 2
        act = {__sigaction_handler = {sa_handler = 0x0, sa_sigaction = 0x0}, sa_mask = {__val = {2922372744, 19, 2922379408, 3061935093, 0, 28, 2922374040, 2923454184, 0, 3061940382, 3061940382, 3061940382, 3062538872, 0, 2922373148, 3010790933, 37, 128, 1, 0, 1, 0, 2922372840, 3010933547, 144, 2923450104, 0, 0, 0, 0, 0, 0}}, sa_flags = 0, sa_restorer = 0xae2fdff0}
        sigs = {__val = {32, 0 <repeats 31 times>}}
#3 0xb68323f8 in __libc_message (do_abort=<optimized out>, fmt=0xb68b0518 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
        ap = {__ap = 0xae2fe03c}
        fd = 2
        on_2 = <optimized out>
        list = <optimized out>
        nlist = <optimized out>
        cp = <optimized out>
        written = <optimized out>