Re: 2.6.27-rc1-mm1: rmmod ide-cd_mod oops

[Bartlomiej Zolnierkiewicz <bzolnier-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hi,

On Saturday 02 August 2008, Mariusz Kozlowski wrote:
> Hi,
> 
> 	rmmod on ide-cd_mod causes this oops:
> 
> BUG: unable to handle kernel paging request at 83535683
> IP: [<c0246ffa>] ide_device_put+0xc/0x33
> *pde = 00000000 
> Oops: 0000 [#1] PREEMPT 
> last sysfs file: /sys/devices/pci0000:00/0000:00:01.0/0000:01:05.0/resource
> Modules linked in: radeon drm nfsd lockd sunrpc exportfs pcmcia uhci_hcd ehci_hcd usbcore snd_ali5451 yenta_socket pcspkr snd_ac97_codec ac97_bus rsrc_nonstatic snd_pcm snd_timer ati_agp agpgart snd soundcore snd_page_alloc ide_cd_mod(-) cdrom 8139too psmouse sony_laptop backlight floppy rtc
> 
> Pid: 3890, comm: rmmod Not tainted (2.6.27-rc1-mm1 #2)
> EIP: 0060:[<c0246ffa>] EFLAGS: 00010286 CPU: 0
> EIP is at ide_device_put+0xc/0x33
> EAX: 83535657 EBX: dc927a00 ECX: 00000003 EDX: 00000001
> ESI: dec34e34 EDI: dec34e34 EBP: d9f46ee0 ESP: d9f46edc
>  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
> Process rmmod (pid: 3890, ti=d9f46000 task=dd88e780 task.ti=d9f46000)
> Stack: dc927c00 d9f46eec dec2e202 dc927c00 d9f46ef8 dec2e225 dd9138dc d9f46f00 
>        c02469e0 d9f46f10 c024156f dd9138dc dd9139f4 d9f46f24 c024162c 00000880 
>        dec34e34 c0397dc0 d9f46f38 c0240a33 00000880 dec34e34 00000000 d9f46f48 
> Call Trace:
>  [<dec2e202>] ? ide_cd_put+0x26/0x33 [ide_cd_mod]
>  [<dec2e225>] ? ide_cd_remove+0x16/0x19 [ide_cd_mod]
>  [<c02469e0>] ? generic_ide_remove+0x1a/0x1e
>  [<c024156f>] ? __device_release_driver+0x59/0x7f
>  [<c024162c>] ? driver_detach+0x97/0x99
>  [<c0240a33>] ? bus_remove_driver+0x6f/0x8b
>  [<c02419f1>] ? driver_unregister+0x2f/0x33
>  [<dec31331>] ? ide_cdrom_exit+0xd/0xf [ide_cd_mod]
>  [<c014265a>] ? sys_delete_module+0x10d/0x1e2
>  [<c015fedc>] ? do_munmap+0x1d7/0x234
>  [<c01e8684>] ? trace_hardirqs_on_thunk+0xc/0x10
>  [<c0103015>] ? sysenter_do_call+0x12/0x35
>  =======================
> Code: ff ff 89 44 24 08 c7 44 24 04 a7 de 35 c0 89 34 24 e8 cb ce f9 ff 31 c0 83 c4 0c 5b 5e 5d c3 55 89 e5 53 89 c3 8b 40 24 8b 40 10 <8b> 40 2c 85 c0 74 12 8b 80 44 01 00 00 8b 40 08 85 c0 74 05 e8 
> EIP: [<c0246ffa>] ide_device_put+0xc/0x33 SS:ESP 0068:d9f46edc
> ---[ end trace a2eed48430d87636 ]---
> 
> this is easily reporoducible, more investigation points here:

Unfortunately, I'm unable to reproduce it here with 2.6.27-rc1-mm1.

Which IDE host driver is it happening with?  Could you send me your .config?

> (gdb) l *ide_device_put+0xc
> 0xc0246ffa is in ide_device_put (/home/mako/linux/lkt/sources/linux-2.6.27-rc1-mm1/drivers/ide/ide.c:717).
> 712      * the underlying LLDD module.
> 713      */
> 714     void ide_device_put(ide_drive_t *drive)
> 715     {
> 716     #ifdef CONFIG_MODULE_UNLOAD
> 717             struct device *host_dev = drive->hwif->host->dev[0]; <--------------------------

Could you please check whether it is drive->hwif or hwif->host exploding?

[ hmm, both should never be changed after host driver initialization ]

> 718             struct module *module = host_dev ? host_dev->driver->owner : NULL;
> 719     
> 720             if (module)
> 721                     module_put(module);
> 
> 	Mariusz