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Bug 395441

Summary: knfsd fails to respond to v3 LOOKUP CALL for /dev
Product: Gentoo Linux Reporter: Joe Harvell <landshark>
Component: [OLD] Core systemAssignee: Gentoo Kernel Bug Wranglers and Kernel Maintainers <kernel>
Status: RESOLVED CANTFIX    
Severity: normal CC: net-fs
Priority: Normal    
Version: unspecified   
Hardware: AMD64   
OS: Linux   
Whiteboard:
Package list:
Runtime testing required: ---
Attachments: emerge --info from NFS server host
packet capture on NFS Server host

Description Joe Harvell 2011-12-21 03:40:46 UTC
My diskless client machine hangs during boot waiting for response to NFSv3 LOOKUP CALL for /dev.  wireshark at NFS server machine shows repeated retransmissions with no response.

Reboot of NFS server host clears hang and allows diskless client to finish mounting rootfs and boot.

Hang during boot does not happen every time.

Captured debug (0x7fff) for rpc, nfs and nfsd

Reproducible: Sometimes

Steps to Reproduce:
1. Boot diskless system
2.
3.
Actual Results:  
Diskless system hangs just after mounting root filesystem

Expected Results:  
Diskless system boots

Attached kernel logs and packet capture
Comment 1 Joe Harvell 2011-12-21 03:45:55 UTC
Created attachment 296521 [details]
emerge --info from NFS server host
Comment 2 Joe Harvell 2011-12-21 03:57:56 UTC
Created attachment 296523 [details]
packet capture on NFS Server host

capture interface btm.14.  No capture filters.
Comment 3 Joe Harvell 2011-12-21 04:06:47 UTC
Kernel logs:
This excerpt was taken having echoed 32767 to the following files in /proc/sys/sunrpc: rpc_debug, nfs_debug, nfsd_debug, nlm_debug.

Dec 20 20:52:23 saluki kernel: [40356.620014] revisit canceled
Dec 20 20:52:23 saluki kernel: [40356.620022] nfsd: Dropping request; may be revisited later
Dec 20 20:52:23 saluki kernel: [40356.620029] svc: svc_process dropit
Dec 20 20:52:23 saluki kernel: [40356.620031] svc: xprt ffff880158664000 dropped request
Dec 20 20:52:23 saluki kernel: [40356.620034] svc: service ffff880157c1a000, releasing skb ffff8801588f3780
Dec 20 20:52:23 saluki kernel: [40356.620037] RPC:       Want update, refage=120, age=72
Dec 20 20:52:23 saluki kernel: [40356.620042] svc: transport ffff880158664000 served by daemon ffff88014ed58000
Dec 20 20:52:23 saluki kernel: [40356.620047] svc: server ffff880157c1a000 waiting for data (to = 900000)
Dec 20 20:52:23 saluki kernel: [40356.620051] svc: server ffff88014ed58000, pool 0, transport ffff880158664000, inuse=307
Dec 20 20:52:23 saluki kernel: [40356.620055] svc: got len=-11
Dec 20 20:52:23 saluki kernel: [40356.620058] svc: server ffff88014ed58000 waiting for data (to = 900000)
Dec 20 20:52:24 saluki kernel: [40357.620013] revisit canceled
Dec 20 20:52:24 saluki kernel: [40357.620021] nfsd: Dropping request; may be revisited later
Dec 20 20:52:24 saluki kernel: [40357.620028] svc: svc_process dropit
Dec 20 20:52:24 saluki kernel: [40357.620030] svc: xprt ffff880158664000 dropped request
Dec 20 20:52:24 saluki kernel: [40357.620033] svc: service ffff88014e812000, releasing skb ffff8801587eab80
Dec 20 20:52:24 saluki kernel: [40357.620037] RPC:       Want update, refage=120, age=73
Dec 20 20:52:24 saluki kernel: [40357.620039] svc: transport ffff880158664000 served by daemon ffff88014ed58000
Dec 20 20:52:24 saluki kernel: [40357.620045] svc: server ffff88014e812000 waiting for data (to = 900000)
Dec 20 20:52:24 saluki kernel: [40357.620050] svc: server ffff88014ed58000, pool 0, transport ffff880158664000, inuse=306
Dec 20 20:52:24 saluki kernel: [40357.620054] svc: got len=-11
Dec 20 20:52:24 saluki kernel: [40357.620056] svc: server ffff88014ed58000 waiting for data (to = 900000)
Dec 20 20:52:24 saluki kernel: [40357.737095] svc: socket ffff880158664000(inet ffff880158ef3c80), count=112, busy=0
Dec 20 20:52:24 saluki kernel: [40357.737099] svc: transport ffff880158664000 served by daemon ffff88014ed58000
Dec 20 20:52:24 saluki kernel: [40357.737120] svc: server ffff88014ed58000, pool 0, transport ffff880158664000, inuse=306
Dec 20 20:52:24 saluki kernel: [40357.737124] svc: got len=104
Dec 20 20:52:24 saluki kernel: [40357.737126] svc: transport ffff880158664000 served by daemon ffff88014e812000
Dec 20 20:52:24 saluki kernel: [40357.737131] svc: svc_authenticate (1)
Dec 20 20:52:24 saluki kernel: [40357.737135] svc: server ffff88014e812000, pool 0, transport ffff880158664000, inuse=307
Dec 20 20:52:24 saluki kernel: [40357.737139] svc: got len=-11
Dec 20 20:52:24 saluki kernel: [40357.737141] RPC:       Want update, refage=120, age=63
Dec 20 20:52:24 saluki kernel: [40357.737150] svc: server ffff88014e812000 waiting for data (to = 900000)
Dec 20 20:52:24 saluki kernel: [40357.737151] svc: calling dispatcher
Dec 20 20:52:24 saluki kernel: [40357.737152] nfsd_dispatch: vers 3 proc 3
Dec 20 20:52:24 saluki kernel: [40357.737156] nfsd: LOOKUP(3)   20: 00060001 4741c989 96462840 12c280be 157d4384 00000000 dev
Dec 20 20:52:24 saluki kernel: [40357.737159] nfsd: fh_verify(20: 00060001 4741c989 96462840 12c280be 157d4384 00000000)
Dec 20 20:52:24 saluki kernel: [40357.737168] nfsd: nfsd_lookup(fh 20: 00060001 4741c989 96462840 12c280be 157d4384 00000000, dev)
Dec 20 20:52:29 saluki kernel: [40362.620013] revisit canceled
Comment 4 Mike Pagano gentoo-dev 2012-03-04 21:23:05 UTC
Are you still having this issue with later kernels?
Comment 5 Joe Harvell 2012-03-05 03:36:12 UTC
I haven't upgraded the kernel on this box.  I still see the problem, but rarely. I think if it doesn't happen the first time an NFS client connects, then it doesn't happen.

(In reply to comment #4)
> Are you still having this issue with later kernels?
Comment 6 Mike Pagano gentoo-dev 2012-06-22 18:56:16 UTC
Please reopen if this is still an issue with current kernels.