Infinite loop while returning NFSv4 delegations to certain NAS devices on RHEL6
Issue
- File operations on NFSv4 mounts hangs from certain NAS devices on RHEL6.1
- There is no issues with NFSv3 from the same NAS.
- Issue is not seen on RHEL based NFS servers.
-
SysRq shows the following trace in
/var/log/messages
.PID: 2974 TASK: ffff880854a25500 CPU: 1 COMMAND: "vim" #0 [ffff880847aa9a48] schedule at ffffffff814dad09 #1 [ffff880847aa9b10] rpc_wait_bit_killable at ffffffffa0595d14 [sunrpc] #2 [ffff880847aa9b20] __wait_on_bit at ffffffff814dbd5f #3 [ffff880847aa9b70] out_of_line_wait_on_bit at ffffffff814dbe08 #4 [ffff880847aa9be0] __rpc_wait_for_completion_task at ffffffffa0595cee [sunrpc] #5 [ffff880847aa9bf0] nfs4_run_open_task at ffffffffa065ee60 [nfs] #6 [ffff880847aa9c80] nfs4_open_recover_helper at ffffffffa0661345 [nfs] #7 [ffff880847aa9cc0] nfs4_open_recover at ffffffffa0661516 [nfs] #8 [ffff880847aa9d00] nfs4_open_delegation_recall at ffffffffa0665f57 [nfs] #9 [ffff880847aa9d70] __nfs_inode_return_delegation at ffffffffa067380e [nfs] #10 [ffff880847aa9df0] nfs_inode_return_delegation at ffffffffa0673df6 [nfs] #11 [ffff880847aa9e20] nfs_setattr at ffffffffa06486a8 [nfs] #12 [ffff880847aa9e60] notify_change at ffffffff8118e1b8 #13 [ffff880847aa9ed0] sys_fchmodat at ffffffff811704c3 #14 [ffff880847aa9f70] sys_chmod at ffffffff81170518 #15 [ffff880847aa9f80] tracesys at ffffffff8100b388 (via system_call)
Environment
- Red Hat Enterprise Linux 6
- NFSv4 exports from a few vendors
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