kernel BUG at net/sunrpc/sched.c:902 on server-state-recovery and nfs-server-stable git branches

[Bryce Harrington]

The following bug is present in the git HEAD of the
server-state-recovery branch (from Jan 16th).  The bug also occurred
on the nfs-server-stable branch Jan 6th and 9th, but has not been
present in the 3 snapshots taken since then.

The bug occurred at the start of testing during the pynfs run.

I assume this is a known issue that was fixed, and just needs updating
on the server-state-recovery branch.  If not, let me know and I'll
file it in the bug tracker.

Bryce

http://crucible.osdl.org/runs/3635/sysinfo/nfs13.console
---------------------------------------------------------------------------------------------
This is nfs13.nfsv4.pdx.osdl.net (Linux x86_64
2.6.20-rc2-g900bd4a-nfs-server-stable) 23:35:47

nfs13 login: nfsd: last server has exited
nfsd: unexporting all filesystems
NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
NFSD: starting 90-second grace period
*** Run 3635: Running './server -q -a -t nfs12 -o hard,intr -p /' ***
*** Run 3635: Running './server -q -a -t nfs12 -o hard,intr,sec=krb5 -p /' ***
------------[ cut here ]------------
kernel BUG at net/sunrpc/sched.c:902!
invalid opcode: 0000 [1] PREEMPT SMP
CPU 0
Modules linked in: dm_mod
Pid: 7704, comm: mount Not tainted 2.6.20-rc2-g900bd4a-nfs-server-stable #0
RIP: 0010:[<ffffffff805474a3>]  [<ffffffff805474a3>] rpc_release_task+0xd/0xaa
RSP: 0018:ffff81003c9c9738  EFLAGS: 00010297
RAX: ffffffff805470b7 RBX: ffff81003d99b080 RCX: ffff81003a317d68
RDX: ffffffff805470b7 RSI: 0000000000000203 RDI: ffff81003d99b080
RBP: 00000000fffffff3 R08: ffff81003c9c8000 R09: 0000000000000005
R10: 0000000000000000 R11: ffffffff805257f4 R12: ffff81003c9c9750
R13: ffff81003c9c9b48 R14: ffff81003f620220 R15: ffff81003c9c9b48
FS:  00002ac8ca554b00(0000) GS:ffffffff806b0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b0006e0
Process mount (pid: 7704, threadinfo ffff81003c9c8000, task ffff81003c3e70c0)
Stack:  ffff81003d99b080 ffffffff80541fa8 ffff81003c9c9968 0000000000000000
ffff81003db1d080 ffff81003c9c9b48 ffff81003c9c9968 ffffffff803043ab
ffffffff80558c7c ffffffff80566cf0 ffffffff80665dc0 ffff81003c9c9780
Call Trace:
[<ffffffff80541fa8>] rpc_call_sync+0x79/0xb0
[<ffffffff803043ab>] nf<ffffffff80558c7c>] thread_return+0x0/0xe5
[<ffffffff802f2aed>] nfs4_path_walk+0x96/0x277
[<ffffffff80279863>] mntput_no_expire+0x17/0x74
[<ffffffff805516a9>] rpc_mkdir+0x1f5/0x24e
[<ffffffff80262ebb>] cache_alloc_refill+0x18e/0x4eb
[<ffffffff8027f9ab>] simple_pin_fs+0x82/0xa1
[<ffffffff80541ab1>] rpc_setup_pipedir+0x8d/0xc8
[<ffffffff805446e0>] xprt_get+0x9/0x11
[<fffpc_clone_client+0x90/0xdf
[<ffffffff802ee8a2>] nfs4_create_server+0x234/0x37d
[<ffffffff80558c7c>] thread_return+0x0/0xe5
[<ffffffff80558cd3>] thread_return+0x57/0xe5
[<ffffffff80276064>] __d_lookup+0x100/0x14f
[<ffffffff802f5af8>] nfs4_get_sb+0x1f6/0x2e4
[<ffffffff8026dbe1>] __link_path_walk+0xbee/0xcfb
[<ffffffff80279863>] mntput_no_expire+0x17/0x74
[<ffffffff80262ebb>] cache_alloc_refill+0x18e/0x4eb
[<ffffffff8026848f>] vfs_kern_mount+0x4c/0x8b
[<ffffffff80268503>] do_kern_mount+0x35/0x4c
[<ffffffff8027af9d>] do_mount+0x652/0x695
[<ffffffff804f098b>] dev_queue_xmit+0x225/0x22c
[<ffffffff8050a2d6>] ip_output+0x217/0x25b
[<ffffffff80509670>] ip_queue_xmit+0x403/0x45c
[<ffffffff804ea175>] sock_common_recvmsg+0x30/0x43
[<ffffffff804effff80247cd7>] filemap_nopage+0x1ad/0x35e
[<ffffffff8051e786>] tcp_v4_send_check+0x86/0xbc
[<ffffffff80519a12>] tcp_transmit_skb+0x657/0x67c
[<ffffffff804e99ea>] sk_reset_timer+0xf/0x19
[<ffffffff8051aed3>] __tcp_push_pending_frames+0x804/0x89c
[<ffffffff8024ae94>] __alloc_pages+0x52/0x29d
[<ffffffff8027b2cf>] sys_mount+0x8b/0xd5
[<ffffffff8020985e>] system_call+0x7e/0x83rpc_release_task+0xd/0xaa
RSP <ffff81003c9c9738>