Re: [BUG] Linux 2.6.20.2 - unable to handle kernel paging request - still accessing freed memory

Pekka Enberg
2007-03-14T11:23:22Z

Hi Greg,

I think there's some sort of reference counting problem with sysfs in
2.6.20 kernels. Can you please help us debug it further?

On 3/10/07, Chris Rankin <rankincj@yahoo.com> wrote:
> It looks like 2.6.20.2 is still doing Bad Things in /sys.
>
> BUG: unable to handle kernel paging request at virtual address 6b6b6d6b

[snip]

> EIP: 0060:[<c01300ff>] Not tainted VLI
> EFLAGS: 00010202 (2.6.20.2 #1)
> EIP is at module_put+0x20/0x52
> eax: 6b6b6d6b ebx: 6b6b6b6b ecx: 00000001 edx: e7a01000
> esi: edb7e4e4 edi: 6b6b6b6b ebp: e79fd50c esp: e7a01f58
> ds: 007b es: 007b ss: 0068
> Process udevd (pid: 9656, ti=e7a01000 task=f7a46030 task.ti=e7a01000)
> Stack: eba628a0 c0183a1e 00000010 ed570870 e7a641d0 c0151263 00000000 00000000
> f7ff2208 ed570870 f745b678 00000000 ed570870 c014eda0 00000003 00000003
> f745b678 f745b6f8 c014fd99 00000003 00000007 00000003 e7a01000 c0102bde
> Call Trace:
> [<c0183a1e>] sysfs_release+0x2d/0x4c
> [<c0151263>] __fput+0x96/0x13c
> [<c014eda0>] filp_close+0x51/0x58
> [<c014fd99>] sys_close+0x70/0xa7
> [<c0102bde>] sysenter_past_esp+0x5f/0x85
> [<c0270033>] __sched_text_start+0x613/0x971

There's also some previous discussion here:

http://lkml.org/lkml/2007/3/1/114

Pekka