Hi, My NFS Client is CentOS5.3 (2.6.18) and server is SUSE11. When running LTP (ltp-full-20080930), the client crashed. the stack is below. Kernel BUG at fs/nfs/nfs4xdr.c:872 invalid opcode: 0000 [1] SMP last sysfs file: /block/sdb/size CPU 0 Modules linked in: ipv6 xfrm_nalgo crypto_api autofs4 hidp l2cap bluetooth blockvt(PU) nfs(U) lockd(U) fscache nfs_acl sunrpc ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi scsi_transport_iscsi dm_mirror dm_multipath scsi_dh video hwmon backlight sbs i2c_ec button battery asus_acpi acpi_memhotplug ac lp floppy sg pcspkr i2c_piix4 i2c_core pcnet32 mii parport_pc parport shpchp serio_raw dm_raid45 dm_message dm_region_hash dm_log dm_mod dm_mem_cache ata_piix libata mptspi mptscsih mptbase scsi_transport_spi sd_mod scsi_mod ext3 jbd uhci_hcd ohci_hcd ehci_hcd Pid: 18655, comm: mknod01 Tainted: P 2.6.18-128.el5 #1 RIP: 0010:[<ffffffff8844841d>] [<ffffffff8844841d>] :nfs:encode_share_access+0x6d/0x82 RSP: 0018:ffff81000d4cdb18 EFLAGS: 00010297 RAX: 00000000ffffffff RBX: ffff810007c770b8 RCX: ffff810007c770b8 RDX: 0000000000000008 RSI: 0000000000000008 RDI: ffff81000d4cdb68 RBP: 0000000000000080 R08: ffff810007c770ac R09: 0000000000000009 R10: ffff81000601e980 R11: ffffffff8844bc69 R12: ffff81000d4cdb68 R13: ffff81000216d158 R14: ffff81000d4cde18 R15: ffff810002912000 FS: 00002b7f2d2c3210(0000) GS:ffffffff803ac000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000003ec6a41900 CR3: 0000000007c10000 CR4: 00000000000006e0 Process mknod01 (pid: 18655, threadinfo ffff81000d4cc000, task ffff810004308040) Stack: ffff810004308040 ffff810007c770b0 ffff81000834f408 ffffffff8844b919 ffff8100080b7df8 ffff81000216d158 ffff81000834f408 ffffffff8844bc69 ffff81000216d158 ffffffff8844bcd6 ffff810007c770c0 ffff81000216d160 Call Trace: [<ffffffff8844b919>] :nfs:encode_open+0x66/0x33e [<ffffffff8844bc69>] :nfs:nfs4_xdr_enc_open+0x0/0xac [<ffffffff8844bcd6>] :nfs:nfs4_xdr_enc_open+0x6d/0xac [<ffffffff8844bc69>] :nfs:nfs4_xdr_enc_open+0x0/0xac [<ffffffff883c63f0>] :sunrpc:call_transmit+0x1bc/0x222 [<ffffffff883cb923>] :sunrpc:__rpc_execute+0x92/0x24e [<ffffffff883cbb36>] :sunrpc:rpc_run_task+0x37/0x3f [<ffffffff884430e0>] :nfs:_nfs4_proc_open+0x50/0x1aa [<ffffffff88443ff2>] :nfs:nfs4_do_open+0xc2/0x1dd [<ffffffff884459a4>] :nfs:nfs4_proc_create+0x7f/0x1b2 [<ffffffff883cc91a>] :sunrpc:rpcauth_lookup_credcache+0x12e/0x24c [<ffffffff8842d3c4>] :nfs:nfs_access_get_cached+0xab/0xfa [<ffffffff8842e440>] :nfs:nfs_create+0x87/0xed [<ffffffff8002221b>] d_alloc+0x174/0x1a9 [<ffffffff8003a031>] vfs_create+0xe6/0x158 [<ffffffff800e3120>] sys_mknodat+0x107/0x188 [<ffffffff8005d229>] tracesys+0x71/0xe0 [<ffffffff8005d28d>] tracesys+0xd5/0xe0 Code: 0f 0b 68 14 5e 45 88 c2 68 03 c7 03 00 00 00 00 41 5a 5b 5d RIP [<ffffffff8844841d>] :nfs:encode_share_access+0x6d/0x82 RSP <ffff81000d4cdb18> <0>Kernel panic - not syncing: Fatal exception I think open_flags was set to be zero when calling encode_share_access(), but I don't know what happened and triggered this crash. is anyone willing to help me ? Best, sid