[pnfs] [PATCH] nfsd: handle empty list in move_to_close_lru

[Neil Brown]

On Wednesday January 23, bhalevy at panasas.com wrote:
> Apparently, fs/nfsd/nfs4state.c:move_to_close_lru
> may be called when sop->so_close_lru is empty.

Not empty - invalid!

> Jan 23 12:37:16 bh-testlin1 kernel: RAX: 0000000000200200 RBX: ffff810028118000 RCX: ffffffff8824c5d0
                                           ^^LIST_POISON1^^
> Jan 23 12:37:16 bh-testlin1 kernel: RDX: 0000000000100100 RSI: ffffe20000909cd0 RDI: ffff810028118058
                                           ^^LIST_POISON2^^
> Jan 23 12:37:16 bh-testlin1 kernel: Code: 48 89 42 08 48 8b 35 69 53 02 00 48 89 10 48 c7 c2 70 19 27
                                            ^^^^^^^^^^^
   0:   48 89 42 08               mov    %rax,0x8(%rdx)

%rdx == LIST_POISON2

Could this be caused by the "list_del" in release_stateowner???

If so, list_del_init would fix it.

NeilBrown