[Thinlinc-technical] Kernel panic with Ubuntu 12.10 and mounting/unmounting USB drives with thinlinc

Thu Jul 4 10:12:14 CEST 2013

Hello,

recently we are excessively testing the mounting and unmounting of USB devices through ThinLinc and have came across a problem that seems to prevent us from using the functionality to mount local drives with thinlinc. In fact, what our users are doing are that they insert a USB thumb drive into our Thinclient (NUC). Then they use the tl-mount-localdrives command. Afterwards they "cd" into the corresponding directory, do something and unmount it afterwards using tl-umount-localdrives. This procedure is repeated several times. Unfortunately there seems to be a problem at least with the kernels supplied with ubuntu 12.10 as they seem to crash badly as you can see by the attached crash log.

I am now of course curious if this problem is known, if there exists a workaround or did anyone run into the same problems yet? As said, this behavior currently prevents us from using the local drives mount functionality of thinlinc which we would really love to have.

best regards,
jens

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Jul  4 09:52:35 saturn kernel: [156591.684621] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
Jul  4 09:52:35 saturn kernel: [156591.684659] IP: [<ffffffff811a0062>] commit_tree+0x82/0x100
Jul  4 09:52:35 saturn kernel: [156591.684686] PGD 78da91067 PUD 78da90067 PMD 0 
Jul  4 09:52:35 saturn kernel: [156591.684720] Oops: 0000 [#1] SMP 
Jul  4 09:52:35 saturn kernel: [156591.684744] CPU 50 
Jul  4 09:52:35 saturn kernel: [156591.684751] Modules linked in: ipmi_devintf ipmi_si ipmi_msghandler autofs4 parport_pc ppdev binfmt_misc kvm_amd kvm ghash
_clmulni_intel aesni_intel cryptd aes_x86_64 sp5100_tco microcode psmouse serio_raw joydev amd64_edac_mod fam15h_power k10temp edac_core edac_mce_amd i2c_pii
x4 bnep rfcomm bluetooth mac_hid w83795 w83627ehf hwmon_vid nfsd lp parport nfs lockd fscache auth_rpcgss nfs_acl sunrpc hid_generic usbhid hid pata_atiixp a
hci qla2xxx igb libahci dca scsi_transport_fc megaraid_sas scsi_tgt usb_storage
Jul  4 09:52:35 saturn kernel: [156591.685081] 
Jul  4 09:52:35 saturn kernel: [156591.685089] Pid: 10693, comm: bash Not tainted 3.5.0-34-generic #55-Ubuntu Supermicro H8QG6/H8QG6
Jul  4 09:52:35 saturn kernel: [156591.685133] RIP: 0010:[<ffffffff811a0062>]  [<ffffffff811a0062>] commit_tree+0x82/0x100
Jul  4 09:52:35 saturn kernel: [156591.685159] RSP: 0018:ffff881a57971bb8  EFLAGS: 00010212
Jul  4 09:52:35 saturn kernel: [156591.685176] RAX: ffff881a57971b38 RBX: ffff881a57971bf8 RCX: ffff881a57971bb8
Jul  4 09:52:35 saturn kernel: [156591.685265] RDX: ffff881bc5c2dd80 RSI: ffff881bc5c2dd00 RDI: 0000000000000000
Jul  4 09:52:35 saturn kernel: [156591.685345] RBP: ffff881a57971bc8 R08: ffff882006d09e00 R09: 0000000000000100
Jul  4 09:52:35 saturn kernel: [156591.685426] R10: ffffea00203fe780 R11: ffffffffa01c9b00 R12: ffff881bc5c2dd00
Jul  4 09:52:35 saturn kernel: [156591.685521] R13: 0000000000000000 R14: ffff881a57971dd8 R15: ffff882006d09e20
Jul  4 09:52:35 saturn kernel: [156591.685603] FS:  00007faefd820700(0000) GS:ffff881c17c80000(0000) knlGS:00000000e72ffb40
Jul  4 09:52:35 saturn kernel: [156591.685688] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Jul  4 09:52:35 saturn kernel: [156591.685738] CR2: 0000000000000018 CR3: 000000078d908000 CR4: 00000000000407e0
Jul  4 09:52:35 saturn kernel: [156591.685821] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Jul  4 09:52:35 saturn kernel: [156591.685906] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Jul  4 09:52:35 saturn kernel: [156591.685987] Process bash (pid: 10693, threadinfo ffff881a57970000, task ffff881b6565c500)
Jul  4 09:52:35 saturn kernel: [156591.686071] Stack:
Jul  4 09:52:35 saturn kernel: [156591.686108]  ffff881bc5c2dd80 ffff881bc5c2dd80 ffff881a57971c38 ffffffff811a1838
Jul  4 09:52:35 saturn kernel: [156591.686227]  ffff881a57971be8 0000000000000000 ffff882006d09e00 ffff88040ff12b40
Jul  4 09:52:35 saturn kernel: [156591.686331]  ffff881a57971bf8 ffff881a57971bf8 ffff881a57971c48 ffff881a57971dd8
Jul  4 09:52:35 saturn kernel: [156591.686433] Call Trace:
Jul  4 09:52:35 saturn kernel: [156591.686482]  [<ffffffff811a1838>] attach_recursive_mnt+0x1b8/0x1c0
Jul  4 09:52:35 saturn kernel: [156591.686542]  [<ffffffff811a1895>] graft_tree+0x55/0x90
Jul  4 09:52:35 saturn kernel: [156591.686598]  [<ffffffff811a198f>] do_add_mount+0xbf/0xe0
Jul  4 09:52:35 saturn kernel: [156591.686654]  [<ffffffff811a0e8d>] ? mnt_get_count+0x4d/0x70
Jul  4 09:52:35 saturn kernel: [156591.686726]  [<ffffffff811a2507>] finish_automount+0x57/0xf0
Jul  4 09:52:35 saturn kernel: [156591.686784]  [<ffffffff8118dbee>] follow_managed+0x1ae/0x2d0
Jul  4 09:52:35 saturn kernel: [156591.686841]  [<ffffffff8118f661>] lookup_fast+0x1c1/0x310
Jul  4 09:52:35 saturn kernel: [156591.686899]  [<ffffffff8119132c>] path_lookupat+0x11c/0x720
Jul  4 09:52:35 saturn kernel: [156591.686956]  [<ffffffff8118d653>] ? putname+0x33/0x50
Jul  4 09:52:35 saturn kernel: [156591.687011]  [<ffffffff811924d8>] ? user_path_at_empty+0x68/0xa0
Jul  4 09:52:35 saturn kernel: [156591.687073]  [<ffffffff8116e681>] ? kmem_cache_alloc+0x31/0x130
Jul  4 09:52:35 saturn kernel: [156591.687131]  [<ffffffff81191961>] do_path_lookup+0x31/0xc0
Jul  4 09:52:35 saturn kernel: [156591.687187]  [<ffffffff8118d563>] ? getname_flags+0x53/0xf0
Jul  4 09:52:35 saturn kernel: [156591.687244]  [<ffffffff811924cd>] user_path_at_empty+0x5d/0xa0
Jul  4 09:52:35 saturn kernel: [156591.687304]  [<ffffffff811875bb>] ? vfs_stat+0x1b/0x20
Jul  4 09:52:35 saturn kernel: [156591.687360]  [<ffffffff811877ea>] ? sys_newstat+0x1a/0x40
Jul  4 09:52:35 saturn kernel: [156591.687416]  [<ffffffff81192521>] user_path_at+0x11/0x20
Jul  4 09:52:35 saturn kernel: [156591.687473]  [<ffffffff81181853>] sys_chdir+0x23/0x90
Jul  4 09:52:35 saturn kernel: [156591.687532]  [<ffffffff8168a429>] system_call_fastpath+0x16/0x1b
Jul  4 09:52:35 saturn kernel: [156591.687584] Code: 48 8d 42 80 74 22 0f 1f 00 48 89 b8 d8 00 00 00 f0 ff 40 40 48 8b 90 80 00 00 00 48 39 ca 48 8d 42 80 75
 e5 48 8b 55 f0 48 39 ca <48> 8b 47 18 74 15 48 8b 08 4c 8b 4d f8 48 89 42 08 48 89 10 49 
Jul  4 09:52:35 saturn kernel: [156591.687977] RIP  [<ffffffff811a0062>] commit_tree+0x82/0x100
Jul  4 09:52:35 saturn kernel: [156591.688030]  RSP <ffff881a57971bb8>
Jul  4 09:52:35 saturn kernel: [156591.688072] CR2: 0000000000000018
Jul  4 09:52:35 saturn kernel: [156591.688564] ---[ end trace cc8c3aa8321f8b62 ]---
-- cut here --

-- 
Dr. Jens Langner
Helmholtz-Zentrum Dresden-Rossendorf
Institute of Radiopharmaceutical Cancer Research
Department of Positron Emission Tomography
POB 51 01 19, 01314 Dresden, Germany
http://www.hzdr.de/ | +49 351 260 2757

Vorstand: Prof. Dr. Dr. h. c. Roland Sauerbrey
Prof. Dr. Dr. h. c. Peter Joehnk
VR 1693 beim Amtsgericht Dresden

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