[nsd-users] NSD 4.2.0 intermittent segfaults @ libssl ?

[A. Schulze]

Am 12.06.19 um 18:46 schrieb Stuart Henderson:
> On 2019/06/12 18:38, A. Schulze wrote:
>>
>>
>> Am 12.06.19 um 08:16 schrieb Wouter Wijngaards:
>>> Otherwise, perhaps a stack trace of the issue could be useful
>>> to have, or a way to reproduce it.
>>
>> I'm unable to produce core files.
>>
>> - ulimit -c unlimited is set
>> - cat /proc/sys/kernel/core_pattern: /core/corefile
>>
>> /core exist outside and inside chroot and is writeable by nsd user
>> nsd started chroot and without chroot
>> nsd crash but: no corefile :-/
>>
>> Any more magic required?
> 
> Try running nsd in the foreground directly under gdb?

OK here some result:

I use to start nsd as "nsd -d -c /path/to/nsd.conf

this start 3 processes
33786 ?        Ss     0:00  \_ sshd: root at pts/1
33798 pts/1    Ss     0:00  |   \_ -bash
30910 pts/1    S+     0:00  |       \_ /usr/sbin/nsd -c /chroot/etc/nsd/nsd.conf
30911 pts/1    S+     0:00  |           \_ /usr/sbin/nsd -c /chroot/etc/nsd/nsd.conf
32456 pts/1    S+     0:00  |               \_ /usr/sbin/nsd -c /chroot/etc/nsd/nsd.conf

# gdb /usr/sbin/nsd
GNU gdb (Debian 7.12-6) 7.12.0.20161007-git
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Reading symbols from /usr/sbin/nsd...(no debugging symbols found)...done.
(gdb) attach 32456
Attaching to program: /usr/sbin/nsd, process 32456
Reading symbols from /lib/x86_64-linux-gnu/libssl.so.1.1...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libprotobuf-c.so.1...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libfstrm.so.0...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libcrypto.so.1.1...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libev.so.4...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libdl.so.2...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libpthread.so.0...(no debugging symbols found)...done.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Reading symbols from /lib/x86_64-linux-gnu/libm.so.6...(no debugging symbols found)...done.
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libnss_compat.so.2...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libnsl.so.1...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libnss_nis.so.2...(no debugging symbols found)...done.
Reading symbols from /lib/x86_64-linux-gnu/libnss_files.so.2...(no debugging symbols found)...done.
0x00007ffbed5602e3 in epoll_wait () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) continue
Continuing.

{{{{{ now I start "nsd_control force_transfer" @ the SLAVE-Server ... }}}}

Program received signal SIGSEGV, Segmentation fault.
0x00007ffbee331785 in SSL_shutdown () from /lib/x86_64-linux-gnu/libssl.so.1.1
(gdb) bt
#0  0x00007ffbee331785 in SSL_shutdown () from /lib/x86_64-linux-gnu/libssl.so.1.1
#1  0x000055d50cb2ce0e in ?? ()
#2  0x000055d50cb2dfd8 in ?? ()
#3  0x00007ffbed81a413 in ev_invoke_pending () from /lib/x86_64-linux-gnu/libev.so.4
#4  0x00007ffbed81da06 in ev_run () from /lib/x86_64-linux-gnu/libev.so.4
#5  0x00007ffbed81ffd9 in event_base_loop () from /lib/x86_64-linux-gnu/libev.so.4
#6  0x000055d50cb30bdd in ?? ()
#7  0x000055d50cb30fcb in ?? ()
#8  0x000055d50cb3244c in ?? ()
#9  0x000055d50cae3ff7 in ?? ()
#10 0x00007ffbed4972e1 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
#11 0x000055d50cae45fa in ?? ()
(gdb) quit
A debugging session is active.

        Inferior 1 [process 32456] will be detached.

Quit anyway? (y or n) y
Detaching from program: /usr/sbin/nsd, process 32456

Hope, this helps ...

Andreas