(gdb) bt
#0 0x0000000000518124 in __glist_add (left=0x7f4728044ae0, right=0x0, elt=0x7f46a0008680) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/include/gsh_list.h:79
#1 0x0000000000518181 in glist_add (head=0x7f4728044ae0, elt=0x7f46a0008680) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/include/gsh_list.h:92
#2 0x000000000051ad28 in mdcache_get_chunk (parent=0x7f479004c4d0, prev_chunk=0x7f4728044ae0)
at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_lru.c:902
#3 0x0000000000533724 in mdcache_populate_dir_chunk (directory=0x7f479004c4d0, whence=512, dirent=0x7f47735fc468, prev_chunk=0x7f4728044ae0, eod_met=0x7f47735fc467)
at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_helpers.c:2654
#4 0x0000000000535294 in mdcache_readdir_chunked (directory=0x7f479004c4d0, whence=472, dir_state=0x7f47735fc780, cb=0x430a1e <populate_dirent>, attrmask=0, eod_met=0x7f47735fcc7b)
at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_helpers.c:3048
#5 0x0000000000523520 in mdcache_readdir (dir_hdl=0x7f479004c508, whence=0x7f47735fc760, dir_state=0x7f47735fc780, cb=0x430a1e <populate_dirent>, attrmask=0, eod_met=0x7f47735fcc7b)
at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_handle.c:560
#6 0x0000000000431318 in fsal_readdir (directory=0x7f479004c508, cookie=472, nbfound=0x7f47735fcc7c, eod_met=0x7f47735fcc7b, attrmask=0, cb=0x48af8c <nfs3_readdir_callback>,
opaque=0x7f47735fcc30) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/FSAL/fsal_helper.c:1295
#7 0x000000000048ad74 in nfs3_readdir (arg=0x7f46a000aaa8, req=0x7f46a000a3a0, res=0x7f46a000b670)
at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/Protocols/NFS/nfs3_readdir.c:289
#8 0x0000000000454845 in nfs_rpc_process_request (reqdata=0x7f46a000a3a0) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/MainNFSD/nfs_worker_thread.c:1329
#9 0x0000000000455004 in nfs_rpc_valid_NFS (req=0x7f46a000a3a0) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/MainNFSD/nfs_worker_thread.c:1564
#10 0x00007f47eb9ea4d6 in svc_vc_decode (req=0x7f46a000a3a0) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/libntirpc/src/svc_vc.c:815
#11 0x0000000000448249 in nfs_rpc_decode_request (xprt=0x7f46e803aba0, xdrs=0x7f46a00013b0)
at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/MainNFSD/nfs_rpc_dispatcher_thread.c:1341
#12 0x00007f47eb9ea3e7 in svc_vc_recv (xprt=0x7f46e803aba0) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/libntirpc/src/svc_vc.c:788
#13 0x00007f47eb9e6bc5 in svc_rqst_xprt_task (wpe=0x7f46e803adb8) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/libntirpc/src/svc_rqst.c:751
#14 0x00007f47eb9e703a in svc_rqst_epoll_events (sr_rec=0x109bb10, n_events=1) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/libntirpc/src/svc_rqst.c:923
#15 0x00007f47eb9e72dc in svc_rqst_epoll_loop (sr_rec=0x109bb10) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/libntirpc/src/svc_rqst.c:996
#16 0x00007f47eb9e738f in svc_rqst_run_task (wpe=0x109bb10) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/libntirpc/src/svc_rqst.c:1032
#17 0x00007f47eb9f049f in work_pool_thread (arg=0x7f46e803da10) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/libntirpc/src/work_pool.c:176
#18 0x00007f47ebe12e25 in start_thread () from /lib64/libpthread.so.0
#19 0x00007f47eb4dd34d in clone () from /lib64/libc.so.6
(gdb) frame 1
#1 0x0000000000518181 in glist_add (head=0x7f4728044ae0, elt=0x7f46a0008680) at /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/include/gsh_list.h:92
92 in /export/jcloud-zbs/src/jd.com/zfs/FSAL_SkyFS/nfs-ganesha/src/include/gsh_list.h
(gdb) p head->prev
$8 = (struct glist_head *) 0x0
(gdb) p head
$9 = (struct glist_head *) 0x7f4728044ae0