Panic in rpc method 'Filecoin.SealPreCommit1': runtime error

[kaptinlin]

Describe the bug
1 miner with 100+ workers, the rpc connection is not stable.

To Reproduce
Steps to reproduce the behavior:

1. Run '...'
2. See error

storage-sealing/fsm.go:469	sector 7954 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference

Expected behavior
It shouldn't have panic.

Version (run lotus version):
v0.5.10

[kaptinlin]

sector 7366 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference

[ribasushi]

@kaptinlin do you happen to have the full stack-trace of this error?

[kaptinlin]

2020-09-03T07:00:30.128+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 7393 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:01:00.154+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 7332 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:01:33.412+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 2350 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:02:17.165+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 7299 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:02:20.294+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 7085 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:03:03.744+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 7366 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:08:24.923+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 3927 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:08:30.405+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 5490 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:09:00.122+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 6692 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:17:04.986+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 7273 got error event sealing.SectorSealPreCommit2Failed: seal pre commit(2) failed: fatal error calling 'Filecoin.Fetch': panic in rpc method 'Filecoin.Fetch': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:26:12.544+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 6640 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:26:13.401+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 6660 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:26:13.884+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 6663 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:26:18.237+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:469	sector 6639 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:26:19.143+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:451	sector 6420 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T07:26:40.662+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:451	sector 6416 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T08:30:00.554+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:451	sector 7773 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T08:30:01.494+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:451	sector 7759 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T08:30:11.378+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:451	sector 7747 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference
2020-09-03T08:30:13.848+0800	�[33mWARN�[0m	sectors	storage-sealing/fsm.go:451	sector 6680 got error event sealing.SectorSealPreCommit1Failed: seal pre commit(1) failed: fatal error calling 'Filecoin.SealPreCommit1': panic in rpc method 'Filecoin.SealPreCommit1': runtime error: invalid memory address or nil pointer dereference

[kaptinlin]

@ribasushi nope, you may see #3597
They may be related.