Our test cases run into this. Given that I hit this every time and it renders rngd unusable on s390x without a known workaround, I'm setting severity urgent, please shout if anybody disagrees. Thanks.

The info from coredump that I see is

Reading symbols from /usr/sbin/rngd...
Reading symbols from /usr/lib/debug/usr/sbin/rngd-6.15-2.el9.s390x.debug...
[New LWP 279710]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Core was generated by `/usr/sbin/rngd -f'.
Program terminated with signal SIGABRT, Aborted.
#0  __pthread_kill_implementation (threadid=<optimized out>, signo=<optimized out>, no_tid=no_tid@entry=0)
    at pthread_kill.c:44
44            return INTERNAL_SYSCALL_ERROR_P (ret) ? INTERNAL_SYSCALL_ERRNO (ret) : 0;

reproduces with rng-tools-6.15-2.el8.s390x  creating clone

This doesn't reproduce with rng-tools-6.15-1.el9.s390x - hence the Regression keyword.

(In reply to smitterl from comment #3)
> Our test cases run into this. Given that I hit this every time and it
> renders rngd unusable on s390x without a known workaround, I'm setting
> severity urgent, please shout if anybody disagrees. Thanks.

Hi,
1) the workaround should be disabling jitter entropy source by adding "-x jitter" to rngd options.

2) if you still have a coredump file, could you please provide full output of "bt" command in gdb?
unfotunately, "#0 __pthread_kill_implementation" entry does not give us anything.

3)  if you still have a coredump file, can you please provide it and a package "rngd" binary is from?
i mean, not just a package name, but where to get it.

Hi Vladis,

> 2) if you still have a coredump file, could you please provide full output
> of "bt" command in gdb?
> unfotunately, "#0 __pthread_kill_implementation" entry does not give us
> anything.

# ulimit -c unlimited

# /usr/sbin/rngd

# coredumpctl dump -o core

# gdb /usr/sbin/rngd core 
...
Core was generated by `/usr/sbin/rngd'.
Program terminated with signal SIGABRT, Aborted.
#0  __pthread_kill_implementation (threadid=<optimized out>, signo=<optimized out>, no_tid=no_tid@entry=0) at pthread_kill.c:44
44	      return INTERNAL_SYSCALL_ERROR_P (ret) ? INTERNAL_SYSCALL_ERRNO (ret) : 0;
(gdb) bt
#0  __pthread_kill_implementation (threadid=<optimized out>, signo=<optimized out>, no_tid=no_tid@entry=0) at pthread_kill.c:44
#1  0x000003ff93da0196 in __pthread_kill_internal (signo=<optimized out>, threadid=<optimized out>) at pthread_kill.c:78
#2  0x000003ff93d508f0 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#3  0x000003ff93d2a340 in __GI_abort () at abort.c:79
#4  0x000003ff93d92e60 in __libc_message (fmt=fmt@entry=0x3ff93e8e088 "*** %s ***: terminated\n") at ../sysdeps/posix/libc_fatal.c:150
#5  0x000003ff93e256fc in __GI___fortify_fail (msg=msg@entry=0x3ff93e8e070 "stack smashing detected") at fortify_fail.c:24
#6  0x000003ff93e256d8 in __stack_chk_fail () at stack_chk_fail.c:24
#7  0x000003ff94686d00 in jent_get_nstime (out=0x3ffe17f8b28) at ./jitterentropy-base-user.h:139
#8  0x000003ff94687200 in jent_get_nstime_internal (ec=0x2aa1a3cf1c0, out=0x3ffe17f8b28) at src/jitterentropy-timer.c:181
#9  0x000003ff946846b4 in jent_memaccess (ec=0x2aa1a3cf1c0, loop_cnt=0) at src/jitterentropy-noise.c:233
#10 0x000003ff94684804 in jent_measure_jitter (ec=0x2aa1a3cf1c0, loop_cnt=0, ret_current_delta=0x0) at src/jitterentropy-noise.c:353
#11 0x000003ff94682b34 in jent_time_entropy_init (osr=0, flags=48) at src/jitterentropy-base.c:578
#12 0x000003ff94682e5e in jent_entropy_init () at src/jitterentropy-base.c:712
#13 0x000002aa19a0e024 in init_jitter_entropy_source (ent_src=0x2aa19a172b0 <entropy_sources+576>) at rngd_jitter.c:432
#14 init_jitter_entropy_source (ent_src=0x2aa19a172b0 <entropy_sources+576>) at rngd_jitter.c:399
#15 0x000002aa19a049f8 in main (argc=<optimized out>, argv=<optimized out>) at rngd.c:1102

(In reply to Vladis Dronov from comment #8)
 
> 3)  if you still have a coredump file, can you please provide it and a
> package "rngd" binary is from?
> i mean, not just a package name, but where to get it.

Attached new one with actual command that coredumped (see c#0).

(In reply to Ondrej Moriš from comment #11)
> (In reply to Vladis Dronov from comment #8)
>  
> > 3)  if you still have a coredump file, can you please provide it and a
> > package "rngd" binary is from?
> > i mean, not just a package name, but where to get it.
> 
> Attached new one with actual command that coredumped (see c#0).

Typo - c#10. Sorry.

(In reply to Ondrej Moriš from comment #9)
> # gdb /usr/sbin/rngd core 
Filip, thanks for reporting this issue, Ondrej thanks for reproducing and providing full stack stace, this was a great help.

Research details see: https://github.com/smuellerDD/jitterentropy-library/pull/95

Reproduced with jitterentropy-3.4.1-1.el9.s390x and rng-tools-6.15-2.el9.s390x, verified with rng-tools-6.15-3.el9.s390x.rpm and jitterentropy-3.4.1-2.el9.s390x.rpm :

# uname -r
5.14.0-242.el9.s390x
# cat /etc/redhat-release 
Red Hat Enterprise Linux release 9.2 Beta (Plow)
# dnf install rng-tools
(...)
Installed:
  jitterentropy-3.4.1-1.el9.s390x
  rng-tools-6.15-2.el9.s390x
Complete!
# systemctl start rngd
# grep rngd /var/log/messages
Jan 25 12:23:23 ibm-z-536 dracut[1286]: dracut module 'rngd' will not be installed, because command 'rngd' could not be found!
Jan 25 12:23:24 ibm-z-536 dracut[1286]: dracut module 'rngd' will not be installed, because command 'rngd' could not be found!
Jan 25 18:42:41 ibm-z-536 rngd[79567]: Disabling 7: PKCS11 Entropy generator (pkcs11)
Jan 25 18:42:41 ibm-z-536 rngd[79567]: Disabling 5: NIST Network Entropy Beacon (nist)
Jan 25 18:42:41 ibm-z-536 rngd[79567]: Disabling 9: Qrypt quantum entropy beacon (qrypt)
Jan 25 18:42:41 ibm-z-536 rngd[79567]: Initializing available sources
Jan 25 18:42:41 ibm-z-536 rngd[79567]: [hwrng ]: Initialized
Jan 25 18:42:41 ibm-z-536 rngd[79567]: [jitter]: JITTER timeout set to 5 sec
Jan 25 18:42:41 ibm-z-536 rngd[79567]: *** stack smashing detected ***: terminated
Jan 25 18:42:41 ibm-z-536 systemd-coredump[79569]: Resource limits disable core dumping for process 79567 (rngd).
Jan 25 18:42:41 ibm-z-536 systemd-coredump[79569]: Process 79567 (rngd) of user 0 dumped core.
Jan 25 18:42:41 ibm-z-536 systemd[1]: rngd.service: Main process exited, code=dumped, status=6/ABRT
Jan 25 18:42:41 ibm-z-536 systemd[1]: rngd.service: Failed with result 'core-dump'.

# rpm -U rng-tools-6.15-3.el9.s390x.rpm jitterentropy-3.4.1-2.el9.s390x.rpm
# systemctl stop rngd
# systemctl start rngd
# systemctl status rngd
● rngd.service - Hardware RNG Entropy Gatherer Daemon
     Loaded: loaded (/usr/lib/systemd/system/rngd.service; enabled; preset: enabled)
     Active: active (running) since Wed 2023-01-25 18:46:39 EST; 5s ago
   Main PID: 79888 (rngd)
      Tasks: 3 (limit: 36540)
     Memory: 1.5M
        CPU: 10.715s
     CGroup: /system.slice/rngd.service
             └─79888 /usr/sbin/rngd -f --fill-watermark=0 -x pkcs11 -x nist -x qrypt -D daemon:daemon

Jan 25 18:46:39 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: Disabling 7: PKCS11 Entropy generator (pkcs11)
Jan 25 18:46:39 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: Disabling 5: NIST Network Entropy Beacon (nist)
Jan 25 18:46:39 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: Disabling 9: Qrypt quantum entropy beacon (qrypt)
Jan 25 18:46:39 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: Initializing available sources
Jan 25 18:46:39 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: [hwrng ]: Initialized
Jan 25 18:46:39 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: [jitter]: JITTER timeout set to 5 sec
Jan 25 18:46:39 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: [jitter]: Initializing AES buffer
Jan 25 18:46:42 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: [jitter]: Enabling JITTER rng support
Jan 25 18:46:42 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: [jitter]: Initialized
Jan 25 18:46:42 ibm-z-536.lab.eng.rdu2.redhat.com rngd[79888]: Process privileges have been dropped to 2:2

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (jitterentropy bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:2472