While running this script in an attempt to test another sysfs bug: #!/bin/bash while true; do modprobe snd_usb_audio; modprobe -r snd_usb_audio; done & cd /sys/bus/usb/drivers while true; do find . | xargs cat &>/dev/null; done & while true; do find . &>/dev/null; done & I get a few of these: find: WARNING: Hard link count is wrong for .: this may be a bug in your filesystem driver. Automatically turning on find's -noleaf option. Earlier results may have failed to include directories that should have been searched. find: ./snd-usb-audio: No such file or directory shortly followed by this: Unable to handle kernel paging request at ffffffff8851e8ec RIP: [<ffffffff80034af6>] kref_put+0x5e/0x80 PGD 203067 PUD 205063 PMD 734cb067 PTE 0 Oops: 0000 [1] SMP last sysfs file: /bus/usb/drivers/snd-usb-audio/unbind CPU 1 Modules linked in: snd_usb_lib snd_rawmidi snd_hwdep snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd_page_alloc snd_seq_device snd soundcore autofs4 hidp rfcomm l2cap bluetooth sunrpc ip_conntrack_netbios_ns ipt_REJECT xt_state ip_conntrack nfnetlink iptable_filter ip_tables ip6t_REJECT xt_tcpudp ip6table_filter ip6_tables x_tables ipv6 cpufreq_ondemand dm_mirror dm_mod video sbs backlight i2c_ec button battery asus_acpi acpi_memhotplug ac parport_pc lp parport joydev sg ide_cd shpchp cdrom i2c_i801 i2c_core tg3 pcspkr serio_raw ata_piix libata sd_mod scsi_mod ext3 jbd ehci_hcd ohci_hcd uhci_hcd Pid: 21155, comm: cat Not tainted 2.6.18-24.el5 #1 RIP: 0010:[<ffffffff80034af6>] [<ffffffff80034af6>] kref_put+0x5e/0x80 RSP: 0018:ffff81006831fc38 EFLAGS: 00010206 RAX: 000000000000003c RBX: ffffffff8851e8ec RCX: 0000000000000000 RDX: 000000000000003b RSI: ffffffff8013d53f RDI: ffffffff8851e8ec RBP: ffffffff8013d53f R08: 0000000000000000 R09: ffff81007f5c30c0 R10: ffff81007fc96540 R11: ffffffff800fccec R12: ffff8100707026e0 R13: ffff810071c7a4b0 R14: 0000000000000000 R15: 0000000000000000 FS: 00002aaaaaabc260(0000) GS:ffff810037e2c7c0(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: ffffffff8851e8ec CR3: 00000000682ab000 CR4: 00000000000006e0 Process cat (pid: 21155, threadinfo ffff81006831e000, task ffff8100682a87e0) Stack: ffff8100707026e0 ffff810070ba4a60 ffff810070a84cd0 ffffffff800fcd3d ffff810071c7a4b0 ffff81006831fea8 0000000000000000 ffffffff8000cfac 0000000000000000 ffff8100681ba000 ffff81006831fea8 ffffffff8000a255 Call Trace: [<ffffffff800fcd3d>] sysfs_d_iput+0x51/0x7d [<ffffffff8000cfac>] dput+0xf6/0x114 [<ffffffff8000a255>] __link_path_walk+0xd7e/0xf42 [<ffffffff8000e5d7>] link_path_walk+0x5c/0xe5 [<ffffffff801199ee>] inode_has_perm+0x56/0x63 [<ffffffff8000c802>] do_path_lookup+0x270/0x2ec [<ffffffff80023233>] __path_lookup_intent_open+0x56/0x97 [<ffffffff8001a6cc>] open_namei+0x7d/0x6d6 [<ffffffff80119a8f>] file_has_perm+0x94/0xa3 [<ffffffff80027037>] do_filp_open+0x1c/0x38 [<ffffffff8001947d>] do_sys_open+0x44/0xbe [<ffffffff8005b249>] tracesys+0xd1/0xdc Code: 8b 03 ff c8 74 0c f0 ff 0b 0f 94 c0 31 d2 84 c0 74 0a 48 89 RIP [<ffffffff80034af6>] kref_put+0x5e/0x80 RSP <ffff81006831fc38> CR2: ffffffff8851e8ec <0>Kernel panic - not syncing: Fatal exception Hit this on stock 2.6.18-24.el5 on an x86_64