Bug 16931

Using the Ubuntu 2.6.32-24 kernel, I have been getting panics.  The most recent was:

[46664.949052] Kernel panic - not syncing: CRED: put_cred_rcu() sees f0893c00 with usage -238

Unfortunately, that was it for that one, but previously I got:

[  734.637104] ------------[ cut here ]------------
[  734.641023] kernel BUG at /build/buildd/linux-2.6.32/kernel/cred.c:174!
[  734.641023] invalid opcode: 0000 [#1] SMP 
[  734.641023] last sysfs file: /sys/devices/pci0000:00/0000:00:0e.0/host3/target3:0:0/3:0:0:0/block/sdb/sdb1/stat
[  734.641023] Modules linked in: binfmt_misc vboxnetadp vboxnetflt vboxdrv des_generic ipt_MASQUERADE iptable_nat bridge stp kvm_amd kvm autofs4 rpcsec_gss_krb5 nfsd exportfs nfs lockd nfs_acl auth_rpcgss sunrpc xt_hl nf_conntrack_ipv6 xt_limit ipt_REJECT xt_tcpudp ipt_addrtype xt_state ip6table_filter snd_hda_codec_analog snd_emu10k1_synth snd_emux_synth snd_seq_virmidi snd_wavefront snd_cs4236 snd_wss_lib snd_seq_midi_emul snd_opl3_lib ip6_tables xc5000 snd_mpu401 snd_emu10k1 snd_hda_intel snd_mpu401_uart fbcon snd_seq_dummy nf_nat_irc snd_ac97_codec snd_hda_codec tileblit tuner nf_conntrack_irc snd_seq_oss ac97_bus snd_usb_audio snd_usb_lib font snd_pcm_oss au8522 snd_seq_midi nf_nat_ftp snd_mixer_oss bitblit nvidia(P) snd_seq_midi_event nf_nat softcursor agpgart snd_pcm snd_seq snd_rawmidi vga16fb snd_timer snd_util_mem emu10k1_gp snd_page_alloc vgastate snd_hwdep snd_seq_device nf_conntrack_ipv4 hwmon_vid au0828 dvb_core eeprom nf_defrag_ipv4 v4l2_common uvcvideo nf_conntrack_ftp nf_conntrack snd i2c_nforce2 k8temp ppdev videodev videobuf_vmalloc ns558 soundcore parport_pc videobuf_core v4l1_compat gameport asus_atk0110 usblp tveeprom psmouse serio_raw iptable_filter ip_tables x_tables lp parport raid10 raid456 async_raid6_recov async_pq raid6_pq async_xor async_memcpy async_tx raid1 raid0 multipath linear dm_raid45 floppy usb_storage xor ohci1394 ieee1394 forcedeth pata_amd sata_nv
[  734.756869] 
[  734.756869] Pid: 6989, comm: mono Tainted: P           (2.6.32-24-generic #41-Ubuntu) System Product Name
[  734.756869] EIP: 0060:[<c016da6e>] EFLAGS: 00210246 CPU: 1
[  734.756869] EIP is at __put_cred+0x3e/0x50
[  734.756869] EAX: f2398a80 EBX: ef9ff480 ECX: ef9ff900 EDX: d984cc80
[  734.756869] ESI: ef9ff280 EDI: 00000009 EBP: d98ddf00 ESP: d98ddf00
[  734.756869]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[  734.756869] Process mono (pid: 6989, ti=d98dc000 task=d984cc80 task.ti=d98dc000)
[  734.756869] Stack:
[  734.756869]  d98ddf0c c020998d c2a03ea0 d98ddf30 c01a415c 000000ab c07705c0 c2a03eb8
[  734.756869] <0> d99c7e80 00000001 00000024 00000009 d98ddf38 c01a4355 d98ddf80 c0153138
[  734.756869] <0> d98ddf78 c01e6d09 f21ec02c 0bc71a07 000000ab c2a03cc4 c07659e4 000000ab
[  734.756869] Call Trace:
[  734.756869]  [<c020998d>] ? file_free_rcu+0x1d/0x30
[  734.756869]  [<c01a415c>] ? __rcu_process_callbacks+0xfc/0x2d0
[  734.756869]  [<c01a4355>] ? rcu_process_callbacks+0x25/0x50
[  734.756869]  [<c0153138>] ? __do_softirq+0x98/0x1b0
[  734.756869]  [<c01e6d09>] ? handle_mm_fault+0x139/0x390
[  734.756869]  [<c0153295>] ? do_softirq+0x45/0x50
[  734.756869]  [<c01533e5>] ? irq_exit+0x65/0x70
[  734.756869]  [<c059130c>] ? smp_apic_timer_interrupt+0x5c/0x8b
[  734.756869]  [<c0103df1>] ? apic_timer_interrupt+0x31/0x40
[  734.756869] Code: 8c 24 84 c0 3b 82 f8 02 00 00 74 1f 3b 82 f4 02 00 00 74 13 83 c0 64 ba c0 da 16 c0 e8 dc 64 03 00 5d c3 0f 0b eb fe 0f 0b eb fe <0f> 0b eb fe 8d b4 26 00 00 00 00 8d bc 27 00 00 00 00 55 89 e5 
[  734.756869] EIP: [<c016da6e>] __put_cred+0x3e/0x50 SS:ESP 0068:d98ddf00
[  734.936305] ---[ end trace e3caf3628073e1d8 ]---
[  734.940931] Kernel panic - not syncing: Fatal exception in interrupt
[  734.947294] Pid: 6989, comm: mono Tainted: P      D    2.6.32-24-generic #41-Ubuntu
[  734.954952] Call Trace:
[  734.957413]  [<c058a766>] ? printk+0x1d/0x1f
[  734.961696]  [<c058a69e>] panic+0x48/0xf3
[  734.965716]  [<c058dd0d>] oops_end+0xcd/0xd0
[  734.969996]  [<c01068e4>] die+0x54/0x80
[  734.973845]  [<c058d426>] do_trap+0x96/0xc0
[  734.978039]  [<c01049c0>] ? do_invalid_op+0x0/0xa0
[  734.982838]  [<c0104a4b>] do_invalid_op+0x8b/0xa0
[  734.987554]  [<c016da6e>] ? __put_cred+0x3e/0x50
[  734.992184]  [<c016a9eb>] ? hrtimer_forward+0x16b/0x1b0
[  734.997418]  [<c058cecd>] ? _spin_lock+0xd/0x10
[  735.001961]  [<c058d1a3>] error_code+0x73/0x80
[  735.006411]  [<c016da6e>] ? __put_cred+0x3e/0x50
[  735.011038]  [<c020998d>] file_free_rcu+0x1d/0x30
[  735.015753]  [<c01a415c>] __rcu_process_callbacks+0xfc/0x2d0
[  735.021421]  [<c01a4355>] rcu_process_callbacks+0x25/0x50
[  735.026829]  [<c0153138>] __do_softirq+0x98/0x1b0
[  735.031543]  [<c01e6d09>] ? handle_mm_fault+0x139/0x390
[  735.036778]  [<c0153295>] do_softirq+0x45/0x50
[  735.041232]  [<c01533e5>] irq_exit+0x65/0x70
[  735.045515]  [<c059130c>] smp_apic_timer_interrupt+0x5c/0x8b
[  735.051182]  [<c0103df1>] apic_timer_interrupt+0x31/0x40

So something stinky does seem to be happening with "cred"s.