2.6.1 : Kernel oops with rmmod

2.6.1 : Kernel oops with rmmod

[Niraj Kumar]

Hi ,
I am getting kernel oops after rmmod .  I was doing some changes in ufs 
filesystem
(basically , trying to add support for ufs2) and then loaded/unloaded 
the ufs module.
Loading was fine. But rmmod crashed with "Segmentation fault" .

[root@indl195ec kernel]# rmmod -v ufs
rmmod ufs, wait=no
Segmentation fault

[niraj@indl195ec niraj]$ cat /proc/version
Linux version 2.6.1 (root@indl195ec) (gcc version 3.2.3 20030502 (Red 
Hat Linux 3.2.3-20)) #2 Wed Jan 21 14:14:02 IST 2004


I am using the module-init-tools-3.0-pre7 .
The oops message is shown below (taken from dmesg):

Unable to handle kernel NULL pointer dereference at virtual address 00000000
 printing eip:
00000000
*pde = 00000000
Oops: 0000 [#1]
CPU:    0
EIP:    0060:[<00000000>]    Not tainted
EFLAGS: 00210246
EIP is at 0x0
eax: 00000000   ebx: f89dcd80   ecx: 00000000   edx: f89dcd80
esi: 00000000   edi: bffff8f0   ebp: eefec000   esp: eefedf68
ds: 007b   es: 007b   ss: 0068
Process rmmod (pid: 2037, threadinfo=eefec000 task=eefd46a0)
Stack: c0129df3 f89dcd80 bffff8f0 0000003b 00736675 00200086 f099e080 
ca1cb1c6
       00000033 4001a000 ca1cb1c6 00000033 f099e080 00083267 ca1cb867 
00000033
       eefd46a0 eefd4864 00000002 00000013 bffff8f0 bffff900 c010a7c1 
bffff8f0
Call Trace:
 [<c0129df3>] sys_delete_module+0x123/0x161
 [<c010a7c1>] sysenter_past_esp+0x52/0x71
 
Code:  Bad EIP value.



Niraj

Re: 2.6.1 : Kernel oops with rmmod

[Rusty Russell]

In message <400FB64D.2050806@iitbombay.org> you write:
> Hi ,
> I am getting kernel oops after rmmod .  I was doing some changes in ufs 
> filesystem
> (basically , trying to add support for ufs2) and then loaded/unloaded 
> the ufs module.
> Loading was fine. But rmmod crashed with "Segmentation fault" .

Most likely you introduced a bug.  Something you overran, or didn't
clean up?

Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.