The hotplug service is stopped before local file systems are umount-ed / remounted read-only. Unfortunately, this allows for the following situation: 1. A partition on a USB Mass storage device is mounted. 2. Stopping hotplug causes (uhci|ohci|ehci)_hcd to be rmmod-ed. 3. When attempting to umount the file system, the kernel crashes. Reproducible: Always Steps to Reproduce: 1. emerge hotplug 2. Plug in a USB drive. 3. Mount a partition of the USB drive. 4. Shut down/reboot Actual Results: The kernel crashes as follows: scsi0 (0:): rejecting I/O to dead device FAT bread failed in fat_clusters_flush Unable to handle kernel paging request at virtual address e0a1a348 printing eip: e0a3decd *pde = 1fe38067 *pte = 00000000 Oops: 0000 [#1] Modules linked in: nls_iso8859_1 nls_cp437 vfat fat sg floppy nfsd exportfs lockd sunrpc intel_agp agpgart sch_cbq ipt_REJECT ipt_mark ipt_state ipt_MASQUERADE iptable_mangle iptable_filter ip_nat_ftp iptable_nat ip_tables ip_conntrack_ftp ip_conntrack sd_mod usb_storage loop 3c59x usbhid usblp usbcore parport_pc evdev rtc lp parport nvram fan button thermal processor ac isofs nls_base zlib_inflate af_packet non_fatal ide_cd sr_mod scsi_mod cdrom unix reiserfs raid0 md ide_disk pdc202xx_new piix ide_core CPU: 0 EIP: 0060:[<e0a3decd>] Not tainted EFLAGS: 00010282 (2.6.8.1) EIP is at hcd_pci_release+0xd/0x11 [usbcore] eax: dfdddc64 ebx: dfdddcb8 ecx: dfdddcb0 edx: e0a1a320 esi: c028c4dc edi: c028c500 ebp: e0a4f234 esp: dd14aeb4 ds: 007b es: 007b ss: 0068 Process umount (pid: 13105, threadinfo=dd14a000 task=df11c3b0) Stack: e0a39b73 c01bfb44 00000001 dfe18600 dfb02800 e0a3d006 dfdddcb8 c0182cf7 dfb02800 c028c2a8 c028c2c0 dfca6c68 e0a366c9 dfb028f0 c01be05d 00000000 00000000 00000000 00000000 c0182cf7 df03e9c8 e0a5b360 debe638c dfe12480 Call Trace: [<e0a39b73>] usb_host_release+0x10/0x12 [usbcore] [<c01bfb44>] class_dev_release+0x5d/0x65 [<e0a3d006>] usb_destroy_configuration+0xcd/0xed [usbcore] [<c0182cf7>] kobject_cleanup+0x8c/0x8e [<e0a366c9>] usb_release_dev+0x31/0x3f [usbcore] [<c01be05d>] device_release+0x53/0x57 [<c0182cf7>] kobject_cleanup+0x8c/0x8e [<e0a5810b>] scsi_disk_put+0x2a/0x4a [sd_mod] [<e0a584ab>] sd_release+0x36/0x59 [sd_mod] [<c014bee5>] blkdev_put+0x100/0x11b [<c014bebb>] blkdev_put+0xd6/0x11b [<c014a548>] deactivate_super+0x43/0x58 [<c015b85e>] sys_umount+0x3b/0x84 [<c013c2c7>] do_munmap+0xed/0x119 [<c015b8be>] sys_oldumount+0x17/0x1b [<c0105c0f>] syscall_call+0x7/0xb Code: ff 52 28 c3 55 57 89 c7 56 53 89 d3 83 ec 34 e8 19 8d ff ff Expected Results: hotplug should not remove the usb-storage pipeline (sd_mod,*_hcd,usb_storage) if a partition on a usb_storage device is mounted. In this case, the expected result was for the system to go down cleanly. I have observed this behaviour on: - x86 (Pentium 4) - ppc (Apple iBook G4) Please also have a look at a recent thread on the mailing list "linux-usb-devel@lists.sourceforge.net" entitled "[linux-usb-devel] usb_storage crash when writing to USB drive."
This is an upstream bug, nothing gentoo specific here. Please file a bug at bugzilla.kernel.org for this.
