Re: 2.6.12-rc4+ & udev kobject problem

[Vassilis Virvilis <vasvir@iit.demokritos.gr>]

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Greg KH wrote:
  > You should only call modprobe if you actually have a MODALIAS env
> variable, right?  Otherwise it doesn't make much sense :)

Well I know that now. At first I believed the kernel will not invoke the 
hotplug script if MODALIAS is empty.

> 
> And care to modify your modprobe binary to print out exactly which
> module it is loading?

Sure,

Unscientific observation: Echoes, printf and messages are helping it not 
to crash. Also in qemu that the rate of execution is slower crashes are 
rare although I suspect qemu just sits there eating all the cpu cycles 
in case of a crash.

I put a printf just before recursion. Normally modprobe calls insmod 
(routine not program) if the list of modules to load has only one module 
left other wise it extracts and call insmod recursively.

That means module a that depends on module b that depends on module c 
goes like this
a:b:c

loading a no
loading b no
loading c yes
insmod c
insmod b
insmod a

that is if another modprobe process does not interrupt the sequence with 
  its own set of depedencies...

and finally here is the log:

    .bill

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Linux version 2.6.12-rc5 (bill@doddo) (Ýêäïóç gcc 3.3.5 (Debian 1:3.3.5-12)) #19 Fri May 27 11:05:29 EEST 2005
BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
 BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 000000000e000000 (usable)
 BIOS-e820: 00000000ffff0000 - 0000000100000000 (reserved)
224MB LOWMEM available.
On node 0 totalpages: 57344
  DMA zone: 4096 pages, LIFO batch:1
  Normal zone: 53248 pages, LIFO batch:31
  HighMem zone: 0 pages, LIFO batch:1
DMI not present.
ACPI: Unable to locate RSDP
Allocating PCI resources starting at 0e000000 (gap: 0e000000:f1ff0000)
Built 1 zonelists
Kernel command line: root=/dev/sda4 netconsole=@192.168.15.7/,@192.168.15.1/ vga=0xf07
netconsole: local port 6665
netconsole: local IP 192.168.15.7
netconsole: interface eth0
netconsole: remote port 6666
netconsole: remote IP 192.168.15.1
netconsole: remote ethernet address ff:ff:ff:ff:ff:ff
No local APIC present or hardware disabled
mapped APIC to ffffd000 (011c1000)
Initializing CPU#0
PID hash table entries: 1024 (order: 10, 16384 bytes)
Detected 733.397 MHz processor.
Using tsc for high-res timesource
Console: colour VGA+ 80x60
Dentry cache hash table entries: 32768 (order: 5, 131072 bytes)
Inode-cache hash table entries: 16384 (order: 4, 65536 bytes)
Memory: 222032k/229376k available (1341k kernel code, 6800k reserved, 696k data, 156k init, 0k highmem)
Checking if this processor honours the WP bit even in supervisor mode... Ok.
Calibrating delay loop... 490.49 BogoMIPS (lpj=245248)
Mount-cache hash table entries: 512
CPU: After generic identify, caps: 0381b83f 00000000 00000000 00000000 00000000 00000000 00000000
CPU: L1 I Cache: 64K (32 bytes/line), D cache 64K (32 bytes/line)
CPU: L2 Cache: 64K (32 bytes/line)
CPU: After all inits, caps: 0381b93f 00000000 00000000 00000000 00000000 000000dd 00000000
CPU: Centaur VIA Nehemiah stepping 08
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Checking 'hlt' instruction... OK.
checking if image is initramfs... it is
Freeing initrd memory: 2454k freed
NET: Registered protocol family 16
PCI: PCI BIOS revision 2.10 entry at 0xfb0c0, last bus=1
PCI: Using configuration type 1
mtrr: v2.0 (20020519)
ACPI: Subsystem revision 20050309
ACPI: Interpreter disabled.
PCI: Probing PCI hardware
PCI: Probing PCI hardware (bus 00)
PCI: Via IRQ fixup
Boot video device is 0000:01:00.0
request_module: runaway loop modprobe char-major-1-11
request_module: runaway loop modprobe char-major-1-11
request_module: runaway loop modprobe char-major-1-11
request_module: runaway loop modprobe char-major-1-11
request_module: runaway loop modprobe char-major-1-11
PCI: Using IRQ router VIA [1106/0686] at 0000:00:07.0
loading /lib/modules/2.6.12-rc5/kernel/drivers/video/savage/savagefb.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/video/cfbcopyarea.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/video/cfbimgblt.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/video/cfbfillrect.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/video/softcursor.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/video/fb.ko? yes
insmod /lib/modules/2.6.12-rc5/kernel/drivers/video/fb.ko 
Badness in kref_get at lib/kref.c:32
 [<c01a64ca>] kref_get+0x2a/0x30
 [<c01a5b32>] kobject_get+0x12/0x20
 [<c01a587a>] kobject_init+0x2a/0x40
 [<c01a59a5>] kobject_register+0x15/0x60
 [<c012e87d>] mod_sysfs_setup+0x3d/0xb0
 [<c012f9eb>] load_module+0x7db/0xaa0
 [<c012fd32>] sys_init_module+0x52/0x1f0
 [<c0102929>] syscall_call+0x7/0xb
Unable to handle kernel NULL pointer dereference at virtual address 00000000
 printing eip:
c01a5937
*pde = 00000000
Oops: 0002 [#1]
PREEMPT 
Modules linked in:
CPU:    0
EIP:    0060:[<c01a5937>]    Not tainted VLI
EFLAGS: 00010282   (2.6.12-rc5) 
EIP is at kobject_add+0x57/0xb0
eax: c028dac8   ebx: ce819148   ecx: 00000000   edx: ce819164
esi: cd768000   edi: c028dad0   ebp: ce81b000   esp: cd769ee0
ds: 007b   es: 007b   ss: 0068
Process modprobe (pid: 285, threadinfo=cd768000 task=cd75b5d0)
Stack: ce819148 ffffffea 00000000 c01a59ab ce819148 ce819148 ce819148 ce819100 
       c012e87d ce819148 ce800000 00000000 ce819100 c012f9eb ce819100 00000000 
       00000000 0000001e 000004b0 000004b0 00000488 ce8170f0 cd6e11e0 ce819100 
Call Trace:
 [<c01a59ab>] kobject_register+0x1b/0x60
 [<c012e87d>] mod_sysfs_setup+0x3d/0xb0
 [<c012f9eb>] load_module+0x7db/0xaa0
 [<c012fd32>] sys_init_module+0x52/0x1f0
 [<c0102929>] syscall_call+0x7/0xb
Code: 00 89 c7 58 8b 43 28 85 c0 74 2f be 00 e0 ff ff 21 e6 ff 46 14 85 ff 74 56 8b 43 28 83 c0 08 8d 53 1c 8b 48 04 89 43 1c 89 50 04 <89> 11 89 4a 04 8b 46 08 ff 4e 14 a8 08 75 2e 89 7b 24 53 e8 c1 
 <6>note: modprobe[285] exited with preempt_count 1
*** hotplug 'subsystem=pci' 'MODALIAS=pci:v00001106d00003058sv00001106sd00003058bc04sc01i00
' 'DEVPATH=/devices/pci0000:00/0000:00:07.5' ***
*** hotplug 'subsystem=pci' 'MODALIAS=pci:v00001106d00003038sv00000925sd00001234bc0Csc03i00
' 'DEVPATH=/devices/pci0000:00/0000:00:07.3' ***
loading /lib/modules/2.6.12-rc5/kernel/drivers/i2c/chips/via686a.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/i2c/i2c-sensor.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/i2c/i2c-core.ko? yes
insmod /lib/modules/2.6.12-rc5/kernel/drivers/i2c/i2c-core.ko 
loading /lib/modules/2.6.12-rc5/kernel/drivers/usb/host/uhci-hcd.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/usb/core/usbcore.ko? yes
insmod /lib/modules/2.6.12-rc5/kernel/drivers/usb/core/usbcore.ko 
loading /lib/modules/2.6.12-rc5/kernel/sound/pci/snd-via82xx.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/pci/ac97/snd-ac97-codec.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/core/snd-pcm.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/core/snd-timer.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/core/snd-page-alloc.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/drivers/mpu401/snd-mpu401-uart.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/core/snd-rawmidi.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/core/seq/snd-seq-device.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/core/snd.ko? no
loading /lib/modules/2.6.12-rc5/kernel/sound/soundcore.ko? yes
insmod /lib/modules/2.6.12-rc5/kernel/sound/soundcore.ko 
Initializing Cryptographic API
PCI: Disabling Via external APIC routing
*** hotplug 'subsystem=pci' 'MODALIAS=pci:v00001106d00000571sv00001106sd00000571bc01sc01i8a
' 'DEVPATH=/devices/pci0000:00/0000:00:07.1' ***
loading /lib/modules/2.6.12-rc5/kernel/drivers/ide/pci/via82cxxx.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/ide/ide-core.ko? yes
insmod /lib/modules/2.6.12-rc5/kernel/drivers/ide/ide-core.ko 
*** hotplug 'subsystem=pci' 'MODALIAS=pci:v00001106d00000686sv00001106sd00000000bc06sc01i00
' 'DEVPATH=/devices/pci0000:00/0000:00:07.0' ***
serio: i8042 AUX port at 0x60,0x64 irq 12
serio: i8042 KBD port at 0x60,0x64 irq 1
io scheduler noop registered
RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
8139too Fast Ethernet driver 0.9.27
PCI: Found IRQ 11 for device 0000:00:0f.0
PCI: Sharing IRQ 11 with 0000:00:07.5
loading /lib/modules/2.6.12-rc5/kernel/drivers/parport/parport_pc.ko? no
loading /lib/modules/2.6.12-rc5/kernel/drivers/parport/parport.ko? yes
insmod /lib/modules/2.6.12-rc5/kernel/drivers/parport/parport.ko 
eth0: RealTek RTL8139 at 0xce81e000, 00:05:8a:00:82:4b, IRQ 11
eth0:  Identified 8139 chip type 'RTL-8139C'
mice: PS/2 mouse device common for all mice
NET: Registered protocol family 2
IP: routing cache hash table of 2048 buckets, 16Kbytes
TCP established hash table entries: 8192 (order: 4, 65536 bytes)
TCP bind hash table entries: 8192 (order: 3, 32768 bytes)
TCP: Hash tables configured (established 8192 bind 8192)
NET: Registered protocol family 1
Freeing unused kernel memory: 156k freed
input: AT Translated Set 2 keyboard on isa0060/serio0