changelog: A brick process is getting crash due to SIGSEGV in changelog

[mohit84]

A brick process is getting crashed while using glusterfind tool. The glusterfind tool uses changelog xlator and
the xlator has race condition to handle crpc object list so at the time of calling ev_connector thread it is getting
crashed.

Below is the volume configuration

Volume Name: vol_test
Type: Replicate
Status: Started
Snapshot Count: 0
Number of Bricks: 1 x 3 = 3
Transport-type: tcp
Bricks:
Brick1: host1:/bricks/brick1/brick
Brick2: host2:/bricks/brick2/brick
Brick3: host3:/bricks/brick3/brick
Options Reconfigured:
changelog.capture-del-path: on
changelog.changelog: on
storage.build-pgfid: on
performance.io-thread-count: 32
server.event-threads: 16
client.event-threads: 16
transport.address-family: inet
storage.fips-mode-rchecksum: on
nfs.disable: on
performance.client-io-threads: off
cluster.granular-entry-heal: enable

Below is the stack dump from the glusterfsd core

warning: .dynamic section for "/lib64/libm.so.6" is not at the expected address (wrong library or version mismatch?)

warning: .dynamic section for "/lib64/libdl.so.2" is not at the expected address (wrong library or version mismatch?)

warning: .dynamic section for "/lib64/libnss_files.so.2" is not at the expected address (wrong library or version mismatch?)

warning: Could not load shared library symbols for %0*Zx, 0x%0*Zx).
Do you need "set solib-search-path" or "set sysroot"?
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Core was generated by `/usr/sbin/glusterfsd -s srv-rhel-gluster03.pjmt.local --volfile-id vol_dados_jc'.
Program terminated with signal 11, Segmentation fault.
#0  list_del (old=0x7ff6ec0009c0) at ../../../../libglusterfs/src/glusterfs/list.h:72
72	    old->prev->next = old->next;
(gdb) bt
#0  list_del (old=0x7ff6ec0009c0) at ../../../../libglusterfs/src/glusterfs/list.h:72
#1  list_move_tail (head=0x7ff760078408, list=0x7ff6ec0009c0) at ../../../../libglusterfs/src/glusterfs/list.h:99
#2  changelog_ev_connector (data=0x7ff760078338) at changelog-ev-handle.c:236
#3  0x00007ff7743b5ea5 in start_thread (arg=0x7ff73bfff700) at pthread_create.c:307
#4  0x00007ff773c7bb0d in __GI_epoll_pwait (epfd=0, events=0x0, maxevents=0, timeout=0, set=0x0) at ../sysdeps/unix/sysv/linux/epoll_pwait.c:48
#5  0x0000000000000000 in ?? ()
(gdb) list
67	}
68	
69	static inline void
70	list_del(struct list_head *old)
71	{
72	    old->prev->next = old->next;
73	    old->next->prev = old->prev;
74	
75	    old->next = (void *)0xbabebabe;
76	    old->prev = (void *)0xcafecafe;
(gdb) p old
$1 = (struct list_head *) 0x7ff6ec0009c0
(gdb) p *old
$2 = {next = 0xbabebabe, prev = 0xcafecafe}