System panics if compact flash card is removed from IDE card reader without unmounting it first in RHEL5

Issue

• Kernel panic in ide_disk_remove if compact flash card is removed from IDE card reader without first unmounting it
• System will pass to ‘kernel panic’ state if user remove CF card from device and forgets demount device.
• If user does following actions operational system will pass to ‘kernel panic’ state:

1. Insert device
2. Mount device under root user (mount /dev/hdc1 /mnt/cf/)
3. Remove device (without umount)
4. Insert device again
5. Unmount device under root user (umount /mnt/cf/)

6. Remove device

   BUG: unable to handle kernel NULL pointer dereference at virtual address 00000004
    printing eip:
   c0568601
   *pde = 52b24067
   Oops: 0000 [#1]
   SMP 
   last sysfs file: /block/hdc/size
   Modules
   linked in: vfat fat ipt_DSCP xt_MARK xt_mark nls_utf8 loop cppmNmi(U)
   cppmLed(U) cppmGpio(U) adm1021 hwmon i2c_dev tcp_westwood mercury(U)
   ipv6 xt_tcpudp xt_comment xt_state iptable_filter iptable_mangle
   iptable_nat ip_nat ip_conntrack nfnetlink ip_tables x_tables dm_mirror
   dm_mod parport_pc lp parport e1000 i2c_i801 e100 mii pcspkr ide_cs
   i2c_core ata_piix libata sd_mod scsi_mod ext3 jbd ehci_hcd ohci_hcd
   uhci_hcd
   CPU:    0
   EIP:    0060:[<c0568601>]    Not tainted VLI
   EFLAGS: 00010286   (2.6.18-53.el5 #1) 
   EIP is at ide_disk_remove+0x8/0x2b
   eax: c07c1294   ebx: c07c1294   ecx: c07c1340   edx: c05685f9
   esi: 00000000   edi: c0692adc   ebp: c07c17cc   esp: f7c32e84
   ds: 007b   es: 007b   ss: 0068
   Process pccardd (pid: 249, ti=f7c32000 task=f7c30aa0 task.ti=f7c32000)
   Stack: c07c13b8 c07c1340 c0692adc c055df5a c054bc9e c07c1340 c07c1340 c0692480 
          c054be98 00000050 c054b67b c07c1340 c07c1340 00000000 c054a7db c07c1340 
          c07c1200 00000000 00000001 c054a829 c07c1280 c055e93c f793e940 ca33d000 
   Call Trace:
    [<c055df5a>] generic_ide_remove+0x1a/0x1d
    [<c054bc9e>] __device_release_driver+0x5a/0x79
    [<c054be98>] device_release_driver+0x1c/0x2b
    [<c054b67b>] bus_remove_device+0x78/0x8a
    [<c054a7db>] device_del+0xe9/0x12f
    [<c054a829>] device_unregister+0x8/0x10
    [<c055e93c>] ide_unregister+0x91/0x554
    [<f8832018>] ide_release+0x18/0x28 [ide_cs]
    [<f8832030>] ide_detach+0x8/0x14 [ide_cs]
    [<c056ed6b>] pcmcia_device_remove+0x51/0xd1
    [<c054bc9e>] __device_release_driver+0x5a/0x79
    [<c054be98>] device_release_driver+0x1c/0x2b
    [<c054b67b>] bus_remove_device+0x78/0x8a
    [<c054a7db>] device_del+0xe9/0x12f
    [<c054a829>] device_unregister+0x8/0x10
    [<c056ec18>] pcmcia_card_remove+0x58/0x77
    [<c056f366>] ds_event+0x4e/0x7c
    [<c056b34a>] send_event+0x41/0x7e
    [<c056b54e>] socket_shutdown+0xc/0xd1
    [<c056bbd8>] pccardd+0x137/0x1e9
    [<c04202b1>] default_wake_function+0x0/0xc
    [<c056baa1>] pccardd+0x0/0x1e9
    [<c0435f65>] kthread+0xc0/0xeb
    [<c0435ea5>] kthread+0x0/0xeb
    [<c0405c3b>] kernel_thread_helper+0x7/0x10
    =======================
   Code:
   e8 cb c2 ff ff 85 c0 74 04 80 63 54 ef ff 8b 80 00 00 00 89 f0 e8 5d ff
   ff ff 31 c0 83 c4 30 5b 5e 5f c3 57 56 53 8b 70 1c 89 c3 <8b> 56
   04 8b 7e 08 e8 75 5c ff ff 89 f8 e8 7e 9c f3 ff 89 d8 e8 
   EIP: [<c0568601>] ide_disk_remove+0x8/0x2b SS:ESP 0068:f7c32e84