Hello,

Same here, and I'm using autofs with kernel 2.6.38-11-generic #48-Ubuntu SMP Fri Jul 29 19:02:55 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

[ 4212.551980] BUG: Dentry ffff88009c1d6900{i=8572,n=/} still in use (1) [unmount of autofs autofs]
[ 4212.552006] ------------[ cut here ]------------
[ 4212.552009] kernel BUG at /build/buildd/linux-2.6.38/fs/dcache.c:947!
[ 4212.552012] invalid opcode: 0000 [#2] SMP 
[ 4212.552016] last sysfs file: /sys/devices/virtual/bdi/cifs-84/uevent
[ 4212.552019] CPU 1 
[ 4212.552021] Modules linked in: nls_iso8859_1 nls_cp437 vfat fat mmc_block hidp hid binfmt_misc rfcomm sco bnep l2cap vboxnetadp vboxnetflt vboxdrv md4 nls_utf8 cifs cryptd aes_x86_64 aes_generic parport_pc dm_crypt ppdev autofs4 vesafb nfsd exportfs nfs lockd fscache nfs_acl auth_rpcgss sunrpc joydev arc4 nvidia(P) snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_seq_midi uvcvideo videodev v4l2_compat_ioctl32 btusb iwlagn snd_rawmidi bluetooth snd_seq_midi_event iwlcore snd_seq mac80211 snd_timer nvidiabl snd_seq_device snd cfg80211 psmouse soundcore snd_page_alloc serio_raw sony_laptop firewire_sbp2 lp parport firewire_ohci sky2 ahci sdhci_pci sdhci firewire_core crc_itu_t libahci
[ 4212.552089] 
[ 4212.552092] Pid: 5301, comm: automount Tainted: P      D     2.6.38-11-generic #48-Ubuntu Sony Corporation VGN-AW11M_H/VAIO
[ 4212.552100] RIP: 0010:[<ffffffff811799b5>]  [<ffffffff811799b5>] shrink_dcache_for_umount_subtree+0x285/0x290
[ 4212.552110] RSP: 0018:ffff880067c7bde8  EFLAGS: 00010296
[ 4212.552112] RAX: 000000000000006a RBX: ffff88009c1d695c RCX: 000000000000002d
[ 4212.552115] RDX: 0000000000000000 RSI: 0000000000000086 RDI: 0000000000000246
[ 4212.552119] RBP: ffff880067c7be28 R08: 0000000000000033 R09: 0000000000012012
[ 4212.552121] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88009c1d695c
[ 4212.552124] R13: ffff88009c1d6900 R14: ffff88009c1d69a0 R15: 00007f84e9e05620
[ 4212.552128] FS:  00007f84e5243700(0000) GS:ffff8800bdc80000(0000) knlGS:0000000000000000
[ 4212.552131] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4212.552134] CR2: 00007f673aa05000 CR3: 000000011c47b000 CR4: 00000000000006e0
[ 4212.552137] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4212.552140] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 4212.552144] Process automount (pid: 5301, threadinfo ffff880067c7a000, task ffff8801327444a0)
[ 4212.552146] Stack:
[ 4212.552148]  ffff88007a1c2258 ffffffff811771c6 0000000000000000 ffff88007a1c2000
[ 4212.552154]  ffff88009c1d695c ffff88009c1d6900 00007f84e9e05440 00007f84e9e05620
[ 4212.552159]  ffff880067c7be58 ffffffff8117c321 ffff880067c7be48 ffff88007a1c2000
[ 4212.552164] Call Trace:
[ 4212.552170]  [<ffffffff811771c6>] ? pollwake+0x56/0x60
[ 4212.552174]  [<ffffffff8117c321>] shrink_dcache_for_umount+0x51/0x90
[ 4212.552180]  [<ffffffff81166c4c>] generic_shutdown_super+0x2c/0x100
[ 4212.552184]  [<ffffffff81166db6>] kill_anon_super+0x16/0x60
[ 4212.552188]  [<ffffffff81166e27>] kill_litter_super+0x27/0x30
[ 4212.552195]  [<ffffffffa0d4e4d8>] autofs4_kill_sb+0x48/0x60 [autofs4]
[ 4212.552199]  [<ffffffff81167225>] deactivate_locked_super+0x45/0x70
[ 4212.552204]  [<ffffffff81167eaa>] deactivate_super+0x4a/0x70
[ 4212.552209]  [<ffffffff811832d4>] mntput_no_expire+0xa4/0xf0
[ 4212.552213]  [<ffffffff81184360>] sys_umount+0x60/0xd0
[ 4212.552218]  [<ffffffff8100c002>] system_call_fastpath+0x16/0x1b
[ 4212.552220] Code: 8b 40 28 4c 8b 08 49 8b 45 30 48 85 c0 74 07 48 8b 90 a8 00 00 00 48 89 34 24 48 c7 c7 b0 71 7e 81 4c 89 ee 31 c0 e8 e9 6c 44 00 <0f> 0b 0f 0b 0f 1f 80 00 00 00 00 55 48 89 e5 48 83 ec 20 48 89 
[ 4212.552263] RIP  [<ffffffff811799b5>] shrink_dcache_for_umount_subtree+0x285/0x290
[ 4212.552269]  RSP <ffff880067c7bde8>
[ 4212.552272] ---[ end trace bc5dc201918d1444 ]---