Bug 1739360

Description of problem:

gnfs crash with nfs.nlm disable 

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Core was generated by `/usr/sbin/glusterfs -s localhost --volfile-id gluster/nfs -p /var/run/gluster/n'.
Program terminated with signal 11, Segmentation fault.
#0  nlm_priv (this=this@entry=0x7eff74017450) at nlm4.c:2746
2746                    gf_proc_dump_write (key, "%s\n", client->caller_name);
Missing separate debuginfos, use: debuginfo-install glibc-2.17-157.el7_3.5.x86_64 keyutils-libs-1.5.8-3.el7.x86_64 krb5-libs-1.15.1-19.el7.x86_64 libacl-2.2.51-12.el7.x86_64 libattr-2.4.46-12.el7.x86_64 libcom_err-1.42.9-9.el7.x86_64 libgcc-4.8.5-36.el7.x86_64 libselinux-2.5-6.el7.x86_64 libuuid-2.23.2-33.el7_3.2.x86_64 openssl-libs-1.0.2k-16.1.el7.bclinux.x86_64 pcre-8.32-15.el7_2.1.x86_64 sssd-client-1.14.0-43.el7_3.18.x86_64 zlib-1.2.7-17.el7.x86_64
(gdb) bt
#0  nlm_priv (this=this@entry=0x7eff74017450) at nlm4.c:2746
#1  0x00007eff78e400fd in nfs_priv (this=0x7eff74017450) at nfs.c:1702
#2  0x00007eff873cf66d in gf_proc_dump_xlator_info (top=<optimized out>) at statedump.c:502
#3  0x00007eff873cfc00 in gf_proc_dump_info (signum=signum@entry=10, ctx=0x7eff87fd4010) at statedump.c:837
#4  0x00007eff8789c05e in glusterfs_sigwaiter (arg=<optimized out>) at glusterfsd.c:2083
#5  0x00007eff86202dc5 in start_thread () from /lib64/libpthread.so.0
#6  0x00007eff85a2c76d in clone () from /lib64/libc.so.6


Version-Release number of selected component (if applicable):

master branch

How reproducible:

1) gluster v set <VOL> nfs.nlm off
2) gluster v set <VOL> nfs.disable on
3) gluster v set <VOL> nfs.disable off
4) kill -SIGUSR1 <GNFS_PID> // gnfs crash here


Steps to Reproduce:
1.
2.
3.

Actual results:

gnfs crash

Expected results:

gnfs works well with statedump files

Additional info: