On Wed, 2013-09-18 at 11:16 -0400, J. Bruce Fields wrote:
> From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
>
> This fixes a regression since eb6dc19d8e72ce3a957af5511d20c0db0a8bd007
> "RPCSEC_GSS: Share all credential caches on a per-transport basis" which
> could cause an occasional oops in the nfsd code (see below).
>
> The problem was that an auth was left referencing a client that had been
> freed. To avoid this we need to ensure that auths are shared only
> between descendants of a common client; the fact that a clone of an
> rpc_client takes a reference on its parent then ensures that the parent
> client will last as long as the auth.
>
> Also add a comment explaining what I think was the intention of this
> code.
>
> general protection fault: 0000 [#1] PREEMPT SMP
> Modules linked in: rpcsec_gss_krb5 nfsd auth_rpcgss oid_registry nfs_acl lockd sunrpc
> CPU: 3 PID: 4071 Comm: kworker/u8:2 Not tainted 3.11.0-rc2-00182-g025145f #1665
> Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
> Workqueue: nfsd4_callbacks nfsd4_do_callback_rpc [nfsd]
> task: ffff88003e206080 ti: ffff88003c384000 task.ti: ffff88003c384000
> RIP: 0010:[<ffffffffa00001f3>] [<ffffffffa00001f3>] rpc_net_ns+0x53/0x70 [sunrpc]
> RSP: 0000:ffff88003c385ab8 EFLAGS: 00010246
> RAX: 6b6b6b6b6b6b6b6b RBX: ffff88003af9a800 RCX: 0000000000000002
> RDX: ffffffffa00001a5 RSI: 0000000000000001 RDI: ffffffff81e284e0
> RBP: ffff88003c385ad8 R08: 0000000000000001 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000015 R12: ffff88003c990840
> R13: ffff88003c990878 R14: ffff88003c385ba8 R15: ffff88003e206080
> FS: 0000000000000000(0000) GS:ffff88003fd80000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> CR2: 00007fcdf737e000 CR3: 000000003ad2b000 CR4: 00000000000006e0
> Stack:
> ffffffffa00001a5 0000000000000006 0000000000000006 ffff88003af9a800
> ffff88003c385b08 ffffffffa00d52a4 ffff88003c385ba8 ffff88003c751bd8
> ffff88003c751bc0 ffff88003e113600 ffff88003c385b18 ffffffffa00d530c
> Call Trace:
> [<ffffffffa00001a5>] ? rpc_net_ns+0x5/0x70 [sunrpc]
> [<ffffffffa00d52a4>] __gss_pipe_release+0x54/0x90 [auth_rpcgss]
> [<ffffffffa00d530c>] gss_pipe_free+0x2c/0x30 [auth_rpcgss]
> [<ffffffffa00d678b>] gss_destroy+0x9b/0xf0 [auth_rpcgss]
> [<ffffffffa000de63>] rpcauth_release+0x23/0x30 [sunrpc]
> [<ffffffffa0001e81>] rpc_release_client+0x51/0xb0 [sunrpc]
> [<ffffffffa00020d5>] rpc_shutdown_client+0xe5/0x170 [sunrpc]
> [<ffffffff81098a14>] ? cpuacct_charge+0xa4/0xb0
> [<ffffffff81098975>] ? cpuacct_charge+0x5/0xb0
> [<ffffffffa019556f>] nfsd4_process_cb_update.isra.17+0x2f/0x210 [nfsd]
> [<ffffffff819a4ac0>] ? _raw_spin_unlock_irq+0x30/0x60
> [<ffffffff819a4acb>] ? _raw_spin_unlock_irq+0x3b/0x60
> [<ffffffff810703ab>] ? process_one_work+0x15b/0x510
> [<ffffffffa01957dd>] nfsd4_do_callback_rpc+0x8d/0xa0 [nfsd]
> [<ffffffff8107041e>] process_one_work+0x1ce/0x510
> [<ffffffff810703ab>] ? process_one_work+0x15b/0x510
> [<ffffffff810712ab>] worker_thread+0x11b/0x370
> [<ffffffff81071190>] ? manage_workers.isra.24+0x2b0/0x2b0
> [<ffffffff8107854b>] kthread+0xdb/0xe0
> [<ffffffff819a4ac0>] ? _raw_spin_unlock_irq+0x30/0x60
> [<ffffffff81078470>] ? __init_kthread_worker+0x70/0x70
> [<ffffffff819ac7dc>] ret_from_fork+0x7c/0xb0
> [<ffffffff81078470>] ? __init_kthread_worker+0x70/0x70
> Code: a5 01 00 a0 31 d2 31 f6 48 c7 c7 e0 84 e2 81 e8 f4 91 0a e1 48 8b 43 60 48 c7 c2 a5 01 00 a0 be 01 00 00 00 48 c7 c7 e0 84 e2 81 <48> 8b 98 10 07 00 00 e8 91 8f 0a e1 e8
> +3c 4e 07 e1 48 83 c4 18
> RIP [<ffffffffa00001f3>] rpc_net_ns+0x53/0x70 [sunrpc]
> RSP <ffff88003c385ab8>
>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> ---
> net/sunrpc/auth_gss/auth_gss.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> On Tue, Sep 17, 2013 at 06:19:14PM -0400, J. Bruce Fields wrote:
> > fixes the problem. I can send in a proper patch if you think that makes
> > sense....
>
> Here's my attempt.
That looks good. Thanks!
Trond
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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