[LU-4190] LustreError: 18166:0:(genops.c:1570:obd_exports_barrier()) ASSERTION( list_empty(&obd->obd_exports) ) failed:

• Type: Bug
• Resolution: Cannot Reproduce
• Priority: Major
• Affects Version/s: Lustre 2.4.0
• Environment: Lustre2.4.0，with 2 servers and 1 client, kernel version:2.6.32-358.6.2.l2.08; MGSnode: mgs, 1 mdt and 4osts; Failnode: 1mdt and 4 osts
• Severity: 3
• Assignee: Mikhail Pershin
• Reporter: yueyuling

Description

2 servers work normally at active-active status
1、Mount Lustre FS on the client and write and read data;
2、Umount the MDT on the Failnode;
3、Read data on the client from Lustre FS,successfully;
4、Mount the MDT on the Failnode;
5、Umount the MDT on the MGSnode;
6、Read data on the client from Lustre FS,failed;
7、Mount the MDT on the MGSnode,then the MGSnode crash,print information as follow:

LustreError: 18166:0:(genops.c:320:class_newdev()) Device MGC192.168.22.50@tcp already exists at 2, won't add
LustreError: 18166:0:(obd_config.c:374:class_attach()) Cannot create device MGC192.168.22.50@tcp of type mgc : -17
LustreError: 18166:0:(obd_mount.c:196:lustre_start_simple()) MGC192.168.22.50@tcp attach error -17
LustreError: 18166:0:(obd_mount_server.c:844:lustre_disconnect_lwp()) lustre-MDT0000-lwp-MDT0000: Can't end config log lustre-client.
LustreError: 18166:0:(obd_mount_server.c:1426:server_put_super()) lustre-MDT0000: failed to disconnect lwp. (rc=-2)
LustreError: 18166:0:(obd_mount_server.c:1456:server_put_super()) no obd lustre-MDT0000
LustreError: 18166:0:(obd_mount_server.c:135:server_deregister_mount()) lustre-MDT0000 not registered
LustreError: 18166:0:(genops.c:1570:obd_exports_barrier()) ASSERTION( list_empty(&obd->obd_exports) ) failed:
LustreError: 18166:0:(genops.c:1570:obd_exports_barrier()) LBUG
Pid: 18166, comm: mount.lustre

Call Trace:
[<ffffffffa070a8a5>] libcfs_debug_dumpstack+0x55/0x80 [libcfs]
[<ffffffffa070aeb7>] lbug_with_loc+0x47/0xb0 [libcfs]
[<ffffffffa0813d91>] obd_exports_barrier+0x181/0x190 [obdclass]
[<ffffffffa0f1e886>] mgs_device_fini+0xf6/0x5c0 [mgs]
[<ffffffffa083e837>] class_cleanup+0x817/0xe00 [obdclass]
[<ffffffffa0817e2c>] ? class_name2dev+0x7c/0xe0 [obdclass]
[<ffffffffa0842e9b>] class_process_config+0x1b6b/0x2f60 [obdclass]
[<ffffffffa070bb90>] ? cfs_alloc+0x30/0x60 [libcfs]
[<ffffffffa0844723>] class_manual_cleanup+0x493/0xe80 [obdclass]
[<ffffffff8147a1fe>] ? _read_unlock+0xe/0x10
[<ffffffffa0817e2c>] ? class_name2dev+0x7c/0xe0 [obdclass]
[<ffffffffa087fb9d>] server_put_super+0x42d/0x2580 [obdclass]
[<ffffffffa0882440>] server_fill_super+0x750/0x1580 [obdclass]
[<ffffffffa084fc98>] lustre_fill_super+0x1d8/0x530 [obdclass]
[<ffffffffa084fac0>] ? lustre_fill_super+0x0/0x530 [obdclass]
[<ffffffff8114d21f>] get_sb_nodev+0x5f/0xa0
[<ffffffffa08473f5>] lustre_get_sb+0x25/0x30 [obdclass]
[<ffffffff8114c74b>] vfs_kern_mount+0x7b/0x1b0
[<ffffffff8114c8f2>] do_kern_mount+0x52/0x130
[<ffffffff81168912>] do_mount+0x2d2/0x8c0
[<ffffffff81168f90>] sys_mount+0x90/0xe0
[<ffffffff81002f5b>] system_call_fastpath+0x16/0x1b

Message fromKernel panic - not syncing: LBUG
Pid: 18166, comm: mount.lustre Tainted: GF --------------- 2.6.32-358.6.2.l2.08 #2
Call Trace:
[<ffffffff81476fa7>] ? panic+0xa1/0x163
[<ffffffffa070af0b>] ? lbug_with_loc+0x9b/0xb0 [libcfs]
[<ffffffffa0813d91>] ? obd_exports_barrier+0x181/0x190 [obdclass]
[<ffffffffa0f1e886>] ? mgs_device_fini+0xf6/0x5c0 [mgs]
[<ffffffffa083e837>] ? class_cleanup+0x817/0xe00 [obdclass]
[<ffffffffa0817e2c>] ? class_name2dev+0x7c/0xe0 [obdclass]
[<ffffffffa0842e9b>] ? class_process_config+0x1b6b/0x2f60 [obdclass]
[<ffffffffa070bb90>] ? cfs_alloc+0x30/0x60 [libcfs]
[<ffffffffa0844723>] ? class_manual_cleanup+0x493/0xe80 [obdclass]
[<ffffffff8147a1fe>] ? _read_unlock+0xe/0x10
[<ffffffffa0817e2c>] ? class_name2dev+0x7c/0xe0 [obdclass]
[<ffffffffa087fb9d>] ? server_put_super+0x42d/0x2580 [obdclass]
[<ffffffffa0882440>] ? server_fill_super+0x750/0x1580 [obdclass]
[<ffffffffa084fc98>] ? lustre_fill_super+0x1d8/0x530 [obdclass]
[<ffffffffa084fac0>] ? lustre_fill_super+0x0/0x530 [obdclass]
[<ffffffff8114d21f>] ? get_sb_nodev+0x5f/0xa0
[<ffffffffa08473f5>] ? lustre_get_sb+0x25/0x30 [obdclass]
[<ffffffff8114c74b>] ? vfs_kern_mount+0x7b/0x1b0
[<ffffffff8114c8f2>] ? do_kern_mount+0x52/0x130
[<ffffffff81168912>] ? do_mount+0x2d2/0x8c0
[<ffffffff81168f90>] ? sys_mount+0x90/0xe0
[<ffffffff81002f5b>] ? system_call_fastpath+0x16/0x1b
*******show para for nt_memcpy16*******
src: ffff8802e118fc40, dst: ffffc901125a8d70, len: 80
*******show para for panic done*******

Issue Links

• is related to: LU-4916 mount failure when adding failover node to mkfs.lustre