Hi all Recently we migrated an NFS server from a 32-bit environment running kernel 4.14.128 to a 64-bit 5.15.x kernel. The NFS configuration remained unchanged between the two systems. On two separate occasions since the upgrade (5 Jan under 5.15.10, 14 Jan under 5.15.12) the kernel has oopsed at around the time that an NFS client machine is turned on for the day. On both occasions the call trace was essentially identical. The full oops sequence is at the end of this email. The oops was not observed when running the 4.14.128 kernel. Is there anything more I can provide to help track down the cause of the oops? Regards jonathan Oops under 5.15.12: Jan 14 08:48:30 nfssvr kernel: BUG: kernel NULL pointer dereference, address: 0000000000000110 Jan 14 08:48:30 nfssvr kernel: #PF: supervisor read access in kernel mode Jan 14 08:48:30 nfssvr kernel: #PF: error_code(0x0000) - not-present page Jan 14 08:48:30 nfssvr kernel: Oops: 0000 [#1] PREEMPT SMP PTI Jan 14 08:48:30 nfssvr kernel: CPU: 0 PID: 2935 Comm: lockd Not tainted 5.15.12 #1 Jan 14 08:48:30 nfssvr kernel: Hardware name: /DG31PR, BIOS PRG3110H.86A.0038.2007.1221.1757 12/21/2007 Jan 14 08:48:30 nfssvr kernel: RIP: 0010:vfs_lock_file+0x5/0x30 Jan 14 08:48:30 nfssvr kernel: Code: ff ff 41 89 c4 85 c0 0f 84 42 ff ff ff e9 f8 fe ff ff 0f 0b e8 2c bc d2 00 66 66 2e 0f 1f 84 00 00 00 00 00 90 0f 1f 44 00 00 <48> 8b 47 28 49 89 d0 48 8b 80 98 00 00 00 48 85 c0 74 05 e9 f3 dc Jan 14 08:48:30 nfssvr kernel: RSP: 0018:ffffa478401a3c38 EFLAGS: 00010246 Jan 14 08:48:30 nfssvr kernel: RAX: 7fffffffffffffff RBX: 00000000000000e8 RCX: 0000000000000000 Jan 14 08:48:30 nfssvr kernel: RDX: ffffa478401a3c40 RSI: 0000000000000006 RDI: 00000000000000e8 Jan 14 08:48:30 nfssvr kernel: RBP: ffff946ead1ecc00 R08: ffff946f88ab1000 R09: ffff946f88b33a00 Jan 14 08:48:30 nfssvr kernel: R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa657ff30 Jan 14 08:48:30 nfssvr kernel: R13: ffff946e99df7c40 R14: ffff946e82fb0510 R15: ffff946ead1ecc00 Jan 14 08:48:30 nfssvr kernel: FS: 0000000000000000(0000) GS:ffff946fabc00000(0000) knlGS:0000000000000000 Jan 14 08:48:30 nfssvr kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jan 14 08:48:30 nfssvr kernel: CR2: 0000000000000110 CR3: 000000010083a000 CR4: 00000000000006f0 Jan 14 08:48:30 nfssvr kernel: Call Trace: Jan 14 08:48:30 nfssvr kernel: <TASK> Jan 14 08:48:30 nfssvr kernel: nlm_unlock_files+0x6e/0xb0 Jan 14 08:48:30 nfssvr kernel: ? __skb_recv_udp+0x198/0x330 Jan 14 08:48:30 nfssvr kernel: ? _raw_spin_lock+0x13/0x2e Jan 14 08:48:30 nfssvr kernel: ? nlmsvc_traverse_blocks+0x36/0x120 Jan 14 08:48:30 nfssvr kernel: ? preempt_count_add+0x68/0xa0 Jan 14 08:48:30 nfssvr kernel: nlm_traverse_files+0x152/0x280 Jan 14 08:48:30 nfssvr kernel: nlmsvc_free_host_resources+0x27/0x40 Jan 14 08:48:30 nfssvr kernel: nlm_host_rebooted+0x23/0x90 Jan 14 08:48:30 nfssvr kernel: nlmsvc_proc_sm_notify+0xae/0x110 Jan 14 08:48:30 nfssvr kernel: ? nlmsvc_decode_reboot+0x8b/0xc0 Jan 14 08:48:30 nfssvr kernel: nlmsvc_dispatch+0x89/0x180 Jan 14 08:48:30 nfssvr kernel: svc_process_common+0x3ce/0x6f0 Jan 14 08:48:30 nfssvr kernel: ? lockd_inet6addr_event+0xf0/0xf0 Jan 14 08:48:30 nfssvr kernel: svc_process+0xb7/0xf0 Jan 14 08:48:30 nfssvr kernel: lockd+0xca/0x1b0 Jan 14 08:48:30 nfssvr kernel: ? preempt_count_add+0x68/0xa0 Jan 14 08:48:30 nfssvr kernel: ? _raw_spin_lock_irqsave+0x19/0x40 Jan 14 08:48:30 nfssvr kernel: ? set_grace_period+0x90/0x90 Jan 14 08:48:30 nfssvr kernel: kthread+0x141/0x170 Jan 14 08:48:30 nfssvr kernel: ? set_kthread_struct+0x40/0x40 Jan 14 08:48:30 nfssvr kernel: ret_from_fork+0x22/0x30 Jan 14 08:48:30 nfssvr kernel: </TASK> Jan 14 08:48:30 nfssvr kernel: Modules linked in: tun nf_nat_ftp nf_conntrack_ftp xt_REDIRECT xt_nat xt_conntrack xt_tcpudp xt_NFLOG nfnetlink_log nfnetlink iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_filter ip_tables x_tables ipv6 hid_generic usbhid hi Jan 14 08:48:30 nfssvr kernel: CR2: 0000000000000110 Jan 14 08:48:30 nfssvr kernel: ---[ end trace f8f28acee6f24340 ]--- Jan 14 08:48:30 nfssvr kernel: RIP: 0010:vfs_lock_file+0x5/0x30 Jan 14 08:48:30 nfssvr kernel: Code: ff ff 41 89 c4 85 c0 0f 84 42 ff ff ff e9 f8 fe ff ff 0f 0b e8 2c bc d2 00 66 66 2e 0f 1f 84 00 00 00 00 00 90 0f 1f 44 00 00 <48> 8b 47 28 49 89 d0 48 8b 80 98 00 00 00 48 85 c0 74 05 e9 f3 dc Jan 14 08:48:30 nfssvr kernel: RSP: 0018:ffffa478401a3c38 EFLAGS: 00010246 Jan 14 08:48:30 nfssvr kernel: RAX: 7fffffffffffffff RBX: 00000000000000e8 RCX: 0000000000000000 Jan 14 08:48:30 nfssvr kernel: RDX: ffffa478401a3c40 RSI: 0000000000000006 RDI: 00000000000000e8 Jan 14 08:48:30 nfssvr kernel: RBP: ffff946ead1ecc00 R08: ffff946f88ab1000 R09: ffff946f88b33a00 Jan 14 08:48:30 nfssvr kernel: R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa657ff30 Jan 14 08:48:30 nfssvr kernel: R13: ffff946e99df7c40 R14: ffff946e82fb0510 R15: ffff946ead1ecc00 Jan 14 08:48:30 nfssvr kernel: FS: 0000000000000000(0000) GS:ffff946fabc00000(0000) knlGS:0000000000000000 Jan 14 08:48:30 nfssvr kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jan 14 08:48:30 nfssvr kernel: CR2: 0000000000000110 CR3: 000000010083a000 CR4: 00000000000006f0
