> On Jan 12, 2023, at 4:30 AM, Wang Yugui <wangyugui@xxxxxxxxxxxx> wrote: > > Hi, > >> Hi, >> >>> Hi, >>> >>> We noticed a dead lock of 'umount.nfs4 /nfs/scratch -l' >> >> reproducer: >> >> mount /dev/sda1 /mnt/test/ >> mount /dev/sda2 /mnt/scratch/ >> systemctl restart nfs-server.service >> mount.nfs4 127.0.0.1:/mnt/test/ /nfs/test/ >> mount.nfs4 127.0.0.1:/mnt/scratch/ /nfs/scratch/ >> systemctl stop nfs-server.service >> umount -l /nfs/scratch #OK >> umount -l /nfs/test #dead lock >> >> Best Regards >> Wang Yugui (wangyugui@xxxxxxxxxxxx) >> 2023/01/11 >> >>> kernel: 6.1.5-rc1 > > This problem happen on kernel 6.2.0-rc3+(upstream) too. Can you clarify: - By "deadlock" do you mean the system becomes unresponsive, or that just the mount is stuck? - Can you reproduce in a non-loopback scenario: a separate client and server? > Best Regards > Wang Yugui (wangyugui@xxxxxxxxxxxx) > 2023/01/12 > >>> >>> The dmesg output of 'sysrq w' >>> >>> [13493.955032] sysrq: Show Blocked State >>> [13493.959997] task:umount.nfs4 state:D stack:0 pid:3542745 ppid:3542744 flags:0x00004000 >>> [13493.969628] Call Trace: >>> [13493.973003] <TASK> >>> [13493.976018] __schedule+0x2cb/0x880 >>> [13493.980426] ? __bpf_trace_svc_stats_latency+0x10/0x10 [sunrpc] >>> [13493.987342] ? rpc_destroy_wait_queue+0x10/0x10 [sunrpc] >>> [13493.993637] schedule+0x50/0xc0 >>> [13493.997697] rpc_wait_bit_killable+0xd/0x60 [sunrpc] >>> [13494.003671] __wait_on_bit+0x75/0x90 >>> [13494.008168] out_of_line_wait_on_bit+0x91/0xb0 >>> [13494.013547] ? sched_core_clone_cookie+0x90/0x90 >>> [13494.019101] __rpc_execute+0x14b/0x490 [sunrpc] >>> [13494.024603] ? kmem_cache_alloc+0x41/0x530 >>> [13494.029610] rpc_execute+0xc5/0x100 [sunrpc] >>> [13494.034835] rpc_run_task+0x14b/0x1b0 [sunrpc] >>> [13494.040252] rpc_call_sync+0x50/0xa0 [sunrpc] >>> [13494.045566] nfs4_proc_destroy_session+0x80/0x100 [nfsv4] >>> [13494.051926] nfs4_destroy_session+0x24/0x90 [nfsv4] >>> [13494.057767] nfs41_shutdown_client+0xfd/0x120 [nfsv4] >>> [13494.063774] nfs4_free_client+0x21/0xb0 [nfsv4] >>> [13494.069240] nfs_free_server+0x44/0xb0 [nfs] >>> [13494.074418] nfs_kill_super+0x2b/0x40 [nfs] >>> [13494.079490] deactivate_locked_super+0x2c/0x70 >>> [13494.084811] cleanup_mnt+0xb8/0x140 >>> [13494.089147] task_work_run+0x6a/0xb0 >>> [13494.093587] exit_to_user_mode_prepare+0x1b9/0x1c0 >>> [13494.099232] syscall_exit_to_user_mode+0x12/0x30 >>> [13494.104717] do_syscall_64+0x67/0x80 >>> [13494.109125] ? syscall_exit_to_user_mode+0x12/0x30 >>> [13494.114799] ? do_syscall_64+0x67/0x80 >>> [13494.119426] ? do_syscall_64+0x67/0x80 >>> [13494.124042] ? do_syscall_64+0x67/0x80 >>> [13494.128649] ? exc_page_fault+0x64/0x140 >>> [13494.133400] entry_SYSCALL_64_after_hwframe+0x63/0xcd >>> [13494.139306] RIP: 0033:0x7fc32f839e9b >>> [13494.143726] RSP: 002b:00007ffe670f6018 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 >>> [13494.152183] RAX: 0000000000000000 RBX: 000055f4aad71920 RCX: 00007fc32f839e9b >>> [13494.160218] RDX: 0000000000000003 RSI: 0000000000000002 RDI: 000055f4aad72600 >>> [13494.168237] RBP: 0000000000000002 R08: 0000000000000007 R09: 000055f4aad71010 >>> [13494.176277] R10: 00007fc32fbc0bc0 R11: 0000000000000202 R12: 000055f4aad72600 >>> [13494.184313] R13: 00007fc33025f244 R14: 000055f4aad71a30 R15: 000055f4aad71b50 >>> [13494.192334] </TASK> >>> >>> Best Regards >>> Wang Yugui (wangyugui@xxxxxxxxxxxx) >>> 2023/01/11 -- Chuck Lever
