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Date: Fri, 13 Dec 2013 14:02:29 -0500
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Subject: Re: Recently introduced hang on reboot with auth_gss
From: Andy Adamson <androsadamson@gmail.com>
To: Weston Andros Adamson <dros@netapp.com>
Cc: linux-nfs list <linux-nfs@vger.kernel.org>
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On Fri, Dec 13, 2013 at 12:32 PM, Weston Andros Adamson <dros@netapp.com> wrote:
> Commit c297c8b99b07f496ff69a719cfb8e8fe852832ed (SUNRPC: do not fail gss proc NULL calls with EACCES) introduces a hang on reboot if there are any mounts that use AUTH_GSS.
>
> Due to recent changes, this can even happen when mounting sec=sys, because the non-fsid specific operations use KRB5 if possible.
>
> To reproduce:
>
> 1) mount a server with sec=krb5 (or sec=sys if you know krb5 will work for nfs_client ops)
> 2) reboot
> 3) notice hang (output below)
>
>
> I can see why it?s hanging - the reboot forced unmount is happening after gssd is killed, so the upcall will never succeed?. Any ideas on how this should be fixed?  Should we timeout after a certain number of tries? Should we detect that gssd isn?t running anymore (if this is even possible)?

This patch : commit e2f0c83a9de331d9352185ca3642616c13127539
Author: Jeff Layton <jlayton@redhat.com>
Date:   Thu Dec 5 07:34:44 2013 -0500

    sunrpc: add an "info" file for the dummy gssd pipe

solves the "is gssd running" problem.

-->Andy

>
> -dros
>
>
> BUG: soft lockup - CPU#0 stuck for 22s! [kworker/0:1:27]
> Modules linked in: rpcsec_gss_krb5 nfsv4 nfs fscache crc32c_intel ppdev i2c_piix4 aesni_intel aes_x86_64 glue_helper lrw gf128mul serio_raw ablk_helper cryptd i2c_core e1000 parport_pc parport shpchp nfsd auth_rpcgss oid_registry exportfs nfs_acl lockd sunrpc autofs4 mptspi scsi_transport_spi mptscsih mptbase ata_generic floppy
> irq event stamp: 279178
> hardirqs last  enabled at (279177): [<ffffffff814a925c>] restore_args+0x0/0x30
> hardirqs last disabled at (279178): [<ffffffff814b0a6a>] apic_timer_interrupt+0x6a/0x80
> softirqs last  enabled at (279176): [<ffffffff8103f583>] __do_softirq+0x1df/0x276
> softirqs last disabled at (279171): [<ffffffff8103f852>] irq_exit+0x53/0x9a
> CPU: 0 PID: 27 Comm: kworker/0:1 Not tainted 3.13.0-rc3-branch-dros_testing+ #1
> Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
> Workqueue: rpciod rpc_async_schedule [sunrpc]
> task: ffff88007b87a130 ti: ffff88007ad08000 task.ti: ffff88007ad08000
> RIP: 0010:[<ffffffffa00a562d>]  [<ffffffffa00a562d>] rpcauth_refreshcred+0x17/0x15f [sunrpc]
> RSP: 0018:ffff88007ad09c88  EFLAGS: 00000286
> RAX: ffffffffa02ba650 RBX: ffffffff81073f47 RCX: 0000000000000007
> RDX: 0000000000000007 RSI: ffff88007a885d70 RDI: ffff88007a158b40
> RBP: ffff88007ad09ce8 R08: ffff88007a5ce9f8 R09: ffffffffa00993d7
> R10: ffff88007a5ce7b0 R11: ffff88007a158b40 R12: ffffffffa009943d
> R13: 0000000000000a81 R14: ffff88007a158bb0 R15: ffffffff814a925c
> FS:  0000000000000000(0000) GS:ffff88007f200000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f2d03056000 CR3: 0000000001a0b000 CR4: 00000000001407f0
> Stack:
>  ffffffffa009943d ffff88007a5ce9f8 0000000000000000 0000000000000007
>  0000000000000007 ffff88007a885d70 ffff88007a158b40 ffffffffffffff10
>  ffff88007a158b40 0000000000000000 ffff88007a158bb0 0000000000000a81
> Call Trace:
>  [<ffffffffa009943d>] ? call_refresh+0x66/0x66 [sunrpc]
>  [<ffffffffa0099438>] call_refresh+0x61/0x66 [sunrpc]
>  [<ffffffffa00a403b>] __rpc_execute+0xf1/0x362 [sunrpc]
>  [<ffffffff81073f47>] ? trace_hardirqs_on_caller+0x145/0x1a1
>  [<ffffffffa00a42d3>] rpc_async_schedule+0x27/0x32 [sunrpc]
>  [<ffffffff81052974>] process_one_work+0x211/0x3a5
>  [<ffffffff810528d5>] ? process_one_work+0x172/0x3a5
>  [<ffffffff81052eeb>] worker_thread+0x134/0x202
>  [<ffffffff81052db7>] ? rescuer_thread+0x280/0x280
>  [<ffffffff81052db7>] ? rescuer_thread+0x280/0x280
>  [<ffffffff810584a0>] kthread+0xc9/0xd1
>  [<ffffffff810583d7>] ? __kthread_parkme+0x61/0x61
>  [<ffffffff814afd6c>] ret_from_fork+0x7c/0xb0
>  [<ffffffff810583d7>] ? __kthread_parkme+0x61/0x61
> Code: 89 c2 41 ff d6 48 83 c4 58 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 44 00 00 55 48 89 e5 41 56 41 55 41 54 53 48 89 fb 48 83 ec 40 <4c> 8b 6f 20 4d 8b a5 90 00 00 00 4d 85 e4 0f 85 e4 00 00 00 8b--
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