Re: repeatable slab corruption with LTP msgctl08

[Nadia Derbey <Nadia.Derbey@bull.net>]

Nadia Derbey wrote:
> Andrew Morton wrote:
> 
>> Running current mainline on my old 2-way PIII.  Distro is RH FC1.  LTP
>> version is ltp-full-20070228 (lots of retro-computing there).
>>
>> Config is at http://userweb.kernel.org/~akpm/config-vmm.txt
>>
>>
>> ./testcases/bin/msgctl08 crashes after ten minutes or so:
>>
>> slab: Internal list corruption detected in cache 'size-128'(26), slabp 
>> f2905000(20). Hexdump:
>>
>> 000: 00 e0 12 f2 88 32 c0 f7 88 00 00 00 88 50 90 f2
>> 010: 14 00 00 00 0f 00 00 00 00 00 00 00 ff ff ff ff
>> 020: fd ff ff ff fd ff ff ff fd ff ff ff fd ff ff ff
>> 030: fd ff ff ff fd ff ff ff fd ff ff ff fd ff ff ff
>> 040: fd ff ff ff fd ff ff ff 00 00 00 00 fd ff ff ff
>> 050: fd ff ff ff fd ff ff ff 19 00 00 00 17 00 00 00
>> 060: fd ff ff ff fd ff ff ff 0b 00 00 00 fd ff ff ff
>> 070: fd ff ff ff fd ff ff ff fd ff ff ff fd ff ff ff
>> 080: 10 00 00 00
>> ------------[ cut here ]------------
>> kernel BUG at mm/slab.c:2949!
>> invalid opcode: 0000 [#1] SMP Modules linked in:
>>
>> Pid: 3348, comm: msgctl08 Not tainted (2.6.26-rc5 #1)
>> EIP: 0060:[<c017a35b>] EFLAGS: 00010086 CPU: 0
>> EIP is at check_slabp+0xeb/0x100
>> EAX: 00000001 EBX: f2905083 ECX: 00000001 EDX: f20ee670
>> ESI: f2905000 EDI: 00000084 EBP: f4671e88 ESP: f4671e64
>>  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
>> Process msgctl08 (pid: 3348, ti=f4670000 task=f20ee670 task.ti=f4670000)
>> Stack: c0472f2b 00000000 0000001a f2905000 00000014 f7c01500 ffffffff 
>> 0000000e        f2905000 f4671eec c017b69f 00000010 000000d0 f20ee670 
>> f7c032ac 000000d0        f7c01500 0000000e f7c03288 f7c06df0 f29ec088 
>> 00000098 00000000 00000000 Call Trace:
>>  [<c017b69f>] ? cache_alloc_refill+0xcf/0x6b0
>>  [<c017bdd4>] ? __kmalloc+0x154/0x160
>>  [<c0257663>] ? load_msg+0x33/0x150
>>  [<c0257663>] ? load_msg+0x33/0x150
>>  [<c0257dfb>] ? do_msgsnd+0x17b/0x2e0
>>  [<c0257cc9>] ? do_msgsnd+0x49/0x2e0
>>  [<c0126f1f>] ? __do_softirq+0x6f/0x100
>>  [<c0126e58>] ? _local_bh_enable+0x48/0xa0
>>  [<c0257f92>] ? sys_msgsnd+0x32/0x40
>>  [<c0106e12>] ? sys_ipc+0xb2/0x240
>>  [<c0102f58>] ? sysenter_past_esp+0xa5/0xb1
>>  [<c0102f1d>] ? sysenter_past_esp+0x6a/0xb1
>>  =======================
>> Code: 86 fa ff 8b 55 f0 8b 42 38 8d 04 85 1c 00 00 00 39 f8 76 0b 43 
>> f7 c7 0f 00 00 00 75 d2 eb bd c7 04 24 2b 2f 47 c0 e8 85 86 fa ff <0f> 
>> 0b eb fe 83 c4 18 5b 5e 5f 5d c3 8b 56 10 e9 6b ff ff ff 90 EIP: 
>> [<c017a35b>] check_slabp+0xeb/0x100 SS:ESP 0068:f4671e64
>> ---[ end trace d7a2cbbb5a3654be ]---
>>
>>
>> Pekka (or Christoph): could you please decrypt the slab bits for us?
>>
> 
> Andrew,
> 
> Sorry for answering so late (I only saw you e-mail yesterday afternoon).
> I have just run msgctl08, setting msgmni to 1722 and turning on the SLAB 
> debug:
> 
> CONFIG_SLAB=y
> CONFIG_SLABINFO=y
> CONFIG_DEBUG_SLAB=y
> CONFIG_DEBUG_SLAB_LEAK=y
> 
> kernel: linux-2.6.26-rc5-mm1
> ltp: ltp-full-20080430
> 
> But I could not reproduce the bug.
> 
> Will try to investigate more.
> 

Same result with 2.6.26-rc6.
I saw from your config file that you're running a 2.6.26-rc2. Will try 
with that one.

Regards,
Nadia