Re: kmem_cache_destroy: Can't free all objects (2.6)

[Philippe Elie <phil.el@wanadoo.fr>]

Jozsef Kadlecsik wrote:
> Hello,
> 
> I'm working on performance testing netfilter ip_conntrack.  The tested
> machine is a dual Xeon PC with Serverworks chipset and e1000 cards.
> 
> "Calibrating" without ip_conntrack loaded in went fine. However as
> the ip_conntrack module was removed after a test, sometimes I got the
> message:
> 
> slab error in kmem_cache_destroy(): cache `ip_conntrack': Can't free all
> objects
> Call Trace:
>  [<c0136fe9>] kmem_cache_destroy+0xd8/0x116
>  [<f889f3ba>] ip_conntrack_cleanup+0x43/0x6c [ip_conntrack]
>  [<f889d61a>] init_or_cleanup+0x131/0x190 [ip_conntrack]
>  [<f889fc13>] fini+0xf/0x19 [ip_conntrack]
>  [<c012dd76>] sys_delete_module+0x13c/0x169
>  [<c01402ab>] sys_munmap+0x45/0x66
>  [<c0108f9b>] syscall_call+0x7/0xb
> 
> I cannot reliably reproduce the error. Sometimes it comes at the
> first test run, sometimes at say the 20th, but I have never been able to
> run all the planned 150 tests.
> 
> This happens both with 2.5.74 and 2.6.0-test1.

I fixed a bug with exactly this symptom, all object freed but
the cache was retaining some object internally. I look 2.6.0-test1
and the fix is in, apologies if you already did it correctly
but can you double check the bug is really in 2.6.0-test1.

> Slab cache ip_conntrack: 2052678 allocs vs 2052678 frees


> slab error in kmem_cache_destroy(): cache `ip_conntrack': Can't free all objects

regards,
Philippe Elie