Subject: Re: [Bug 10575] New: WARNING: at mm/slub.c:2444

From: Patrick McHardy <[email-masked]>
Date: Tue, 29 Apr 2008 21:14:46 +0200

Andrew Morton wrote:
> (switched to email.  Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
>
> On Tue, 29 Apr 2008 06:31:36 -0700 (PDT) [email-masked] wrote:
>
>   
>>
>> kernel version:
>>
>> cat include/config/kernel.release 
>> 2.6.25-sched-devel.git-x86-latest.git
>>
>> Shutting down the system generated the following errors:
>>
>> Apr 28 00:20:22 funnyman libvirtd: Shutting down on signal 15
>> Apr 28 00:20:25 funnyman kernel: sky2 eth0: Link is down.
>> Apr 28 00:20:25 funnyman xinetd[3373]: Exiting...
>> Apr 28 00:20:30 funnyman kernel: ------------[ cut here ]------------
>> Apr 28 00:20:30 funnyman kernel: WARNING: at mm/slub.c:2444
>> kmem_cache_destroy+0xfe/0x108()
>> Apr 28 00:20:30 funnyman kernel: Modules linked in: rfcomm hidp l2cap bluetooth
>> button ext2 btrfs hfsplus usb_storage nls_utf8 bridge autofs4 nf_conntrack(-)
>> xt_tcpudp x_tables sunrpc loop dm_multipath video output sbs sbshc battery ac
>> ipv6 parport_pc lp parport snd_usb_audio snd_usb_lib snd_rawmidi snd_hwdep
>> snd_hda_intel snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq
>> snd_seq_device snd_pcm_oss sg firewire_ohci snd_mixer_oss snd_pcm firewire_core
>> crc_itu_t snd_timer snd pata_jmicron soundcore serio_raw sky2 snd_page_alloc
>> pcspkr i2c_i801 iTCO_wdt iTCO_vendor_support i2c_core floppy dm_snapshot
>> dm_zero dm_mirror dm_mod ahci ata_generic ata_piix libata sd_mod scsi_mod ext3
>> jbd ehci_hcd ohci_hcd uhci_hcd [last unloaded: xt_state]
>> Apr 28 00:20:30 funnyman kernel: Pid: 11669, comm: modprobe Not tainted
>> 2.6.25-sched-devel.git-x86-latest.git #1
>> Apr 28 00:20:30 funnyman kernel:  [<c042bad6>] warn_on_slowpath+0x46/0x56
>> Apr 28 00:20:30 funnyman kernel:  [<c0415a33>] ? apic_wait_icr_idle+0x16/0x1d
>> Apr 28 00:20:30 funnyman kernel:  [<c0415243>] ?
>> __send_IPI_dest_field+0x50/0x54
>> Apr 28 00:20:30 funnyman kernel:  [<c04020e5>] ? send_IPI_mask+0xd/0xf
>> Apr 28 00:20:30 funnyman kernel:  [<c046773c>] ?
>> get_pageblock_flags_group+0x50/0x6e
>> Apr 28 00:20:30 funnyman kernel:  [<c046777e>] ?
>> get_pageblock_migratetype+0x24/0x27
>> Apr 28 00:20:30 funnyman kernel:  [<c0468472>] ? free_hot_page+0xf/0x11
>> Apr 28 00:20:30 funnyman kernel:  [<c0468494>] ? __free_pages+0x20/0x2b
>> Apr 28 00:20:30 funnyman kernel:  [<c047f471>] ? __free_slab+0xac/0xb4
>> Apr 28 00:20:30 funnyman kernel:  [<c0480754>] kmem_cache_destroy+0xfe/0x108
>> Apr 28 00:20:30 funnyman kernel:  [<f8d337c0>] nf_conntrack_cleanup+0x53/0x7a
>> [nf_conntrack]
>> Apr 28 00:20:30 funnyman kernel:  [<f8d3766d>]
>> nf_conntrack_standalone_fini+0x1c/0x1e [nf_conntrack]
>> Apr 28 00:20:30 funnyman kernel:  [<c044b56f>] sys_delete_module+0x177/0x1af
>> Apr 28 00:20:30 funnyman kernel:  [<c0472c00>] ? remove_vma+0x31/0x53
>> Apr 28 00:20:30 funnyman kernel:  [<c0473468>] ? do_munmap+0x182/0x19c
>> Apr 28 00:20:30 funnyman kernel:  [<c0404bae>] sysenter_past_esp+0x6a/0x90
>> Apr 28 00:20:30 funnyman kernel:  [<c0640000>] ? pci_scan_bridge+0x1dc/0x2eb
>> Apr 28 00:20:30 funnyman hcid[9436]: Got disconnected from the system message
>> bus
>> Apr 28 00:20:30 funnyman kernel:  =======================
>> Apr 28 00:20:30 funnyman rpc.statd[2994]: Caught signal 15, un-registering and
>> exiting.
>> Apr 28 00:20:30 funnyman kernel: ---[ end trace eb2ec02455daeda8 ]---
>> Apr 28 00:20:30 funnyman portmap[11769]: connect from 127.0.0.1 to
>> unset(status): request from unprivileged port
>> Apr 28 00:20:30 funnyman pcscd: pcscdaemon.c:529:signal_trap() Preparing for
>> suicide
>>
>> and mm/slub.c:2444 are as follows:
>>
>>  2433  * Close a cache and release the kmem_cache structure
>>    2434  * (must be used for caches created using kmem_cache_create)
>>    2435  */
>>    2436 void kmem_cache_destroy(struct kmem_cache *s)
>>    2437 {
>>    2438         down_write(&slub_lock);
>>    2439         s->refcount--;
>>    2440         if (!s->refcount) {
>>    2441                 list_del(&s->list);
>>    2442                 up_write(&slub_lock);
>>    2443                 if (kmem_cache_close(s))
>>    2444                         WARN_ON(1);
>>    2445                 sysfs_slab_remove(s);
>>    2446         } else
>>    2447                 up_write(&slub_lock);
>>    2448 }
>>    2449 EXPORT_SYMBOL(kmem_cache_destroy);
>>
>> How to reproduce:
>>
>> Not sure how, as it occur during shutdown.
>>     
>
> Looks like nf_contrack is destroying a slab cache which still has
> live objects.
>
> I think this came up a few days ago but I'm not sure if it was fixed?

I believe Stephen fixed a use-after-free in bridging a few days ago,
are you referring to this? Otherwise a pointer would be appreciated.

In any case, htmldeveloper, could you provide some more information
about your setup, i.e. firewall rules, does the unload happen during
load, ...? Did you also notice the bug on other kernel versions than
sched-devel.git-x86-latest.git? Thanks.