Re: #851412: libsystemd segfaults on mips64el

[Christian Hofstaedtler <zeha@debian.org>]

Control: affects -1 + pdns pdns-recursor

Hi,

pdns and pdns-recursor link against libsystemd, and this bug causes
both of them to just segfault on startup on mips64el.

Tiny reproducer:

(sid_mips64el-dchroot)zeha@eller:~$ cat foo.c 
int main() {
}
(sid_mips64el-dchroot)zeha@eller:~$ make foo LDFLAGS=-lsystemd
cc   -lsystemd  foo.c   -o foo
(sid_mips64el-dchroot)zeha@eller:~$ gdb --args foo
GNU gdb (Debian 7.12-4) 7.12
Copyright (C) 2016 Free Software Foundation, Inc.
This GDB was configured as "mips64el-linux-gnuabi64".
Type "show configuration" for configuration details.
Reading symbols from foo...(no debugging symbols found)...done.
(gdb) run
Starting program: /home/zeha/foo 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/mips64el-linux-gnuabi64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
_IO_new_fclose (warning: GDB can't find the start of the function at 0xfff7f2fd27.

    GDB is unable to find the start of the function at 0xfff7f2fd27
and thus can't determine the size of that function's stack frame.
This means that GDB may be unable to access that stack frame, or
the frames below it.
    This problem is most likely caused by an invalid program counter or
stack pointer.
    However, if you think GDB should simply search farther back
from 0xfff7f2fd27 for code which looks like the beginning of a
function, you can increase the range of the search using the `set
heuristic-fence-post' command.
fp=0x1) at iofclose.c:48
48      iofclose.c: No such file or directory.
(gdb) bt full
#0  _IO_new_fclose (fp=0x1) at iofclose.c:48
        status = <optimized out>
#1  0x000000fff7f2fd28 in ?? () from /lib/mips64el-linux-gnuabi64/libsystemd.so.0
No symbol table info available.
(gdb) quit
A debugging session is active.

        Inferior 1 [process 11890] will be killed.

Quit anyway? (y or n) y
(sid_mips64el-dchroot)zeha@eller:~$ ls -la /etc/machine-id
ls: cannot access '/etc/machine-id': No such file or directory


PS: libsystemd does not appear to have a -dbgsym package.

-- 
christian hofstaedtler <zeha@debian.org>