Re: Regression: 4.5-rc1 (bisect: hugetlb: make mm and fs code explicitly non-modular vs CONFIG_TIMER_STATS)

From: Christian Borntraeger
Date: Thu Jan 28 2016 - 04:49:12 EST

On 01/28/2016 10:40 AM, Hillf Danton wrote:
>>
>> Paul,
>>
>> the commit 3e89e1c5ea842 ("hugetlb: make mm and fs code explicitly non-modular")
>> triggers belows warning/oops, if CONFIG_TIMER_STATS is set.
>>
>> Looking at the patch the only "real" change is the init_call,
>> and indeed
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -2653,7 +2653,7 @@ static int __init hugetlb_init(void)
>> mutex_init(&hugetlb_fault_mutex_table[i]);
>> return 0;
>> }
>> -subsys_initcall(hugetlb_init);
>> +device_initcall(hugetlb_init);
>>
>> /* Should be called on processing a hugepagesz=... option */
>> void __init hugetlb_add_hstate(unsigned int order)
>>
>> makes the problem go away.
>
> Helps more if a patch is delivered.

The problem is that the original change was intentional. So I do not not
what the right fix is.


>
> thanks
> Hillf
>
>> Not sure yet, what CONFIG_TIMER_STATS changes in terms of kobject, though.
>>
>>
>>
>>
>> [ 0.998607] kobject: '(null)' (0000000000000010): is not initialized, yet kobject_get() is being called.
>> [ 0.998620] ------------[ cut here ]------------
>> [ 0.998621] WARNING: at lib/kobject.c:597
>> [ 0.998622] Modules linked in:
>> [ 0.998625] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.5.0-rc1 #174
>> [ 0.998626] task: 0000000232720000 ti: 000000023270c000 task.ti: 000000023270c000
>> [ 0.998628] Krnl PSW : 0704c00180000000 000000000058276c (kobject_get+0x6c/0x90)
>> [ 0.998632] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 EA:3
>> Krnl GPRS: 000000000000006c 0000000232720000 000000000000005c 0000000000000001
>> [ 0.998635] 0000000000287e04 0000000000000000 0000000000dd99a8 0000000000000000
>> [ 0.998636] 0000000000d86008 0000000000000000 0000000000000000 0000000000000000
>> [ 0.998637] 0000000000000010 0000000000000010 0000000000582768 000000023270fbb0
>> [ 0.998643] Krnl Code: 000000000058275c: c02000267259 larl %%r2,a50c0e
>> 0000000000582762: c0e5ffe82b17 brasl %%r14,287d90
>> #0000000000582768: a7f40001 brc 15,58276a
>> >000000000058276c: a7f4ffe2 brc 15,582730
>> 0000000000582770: c010003d24f3 larl %%r1,d27156
>> 0000000000582776: 95001000 cli 0(%%r1),0
>> 000000000058277a: a774ffe6 brc 7,582746
>> 000000000058277e: a7f40001 brc 15,582780
>> [ 0.998653] Call Trace:
>> [ 0.998655] ([<0000000000582768>] kobject_get+0x68/0x90)
>> [ 0.998657] [<000000000058318e>] kobject_add_internal+0x46/0x2e8
>> [ 0.998658] [<0000000000583684>] kobject_add+0x7c/0xd0
>> [ 0.998660] [<0000000000583722>] kobject_create_and_add+0x4a/0x98
>> [ 0.998662] [<00000000002e8ee0>] hugetlb_register_node+0x68/0x130
>> [ 0.998663] [<0000000000d59ef0>] hugetlb_init+0x4f0/0x600
>> [ 0.998665] [<00000000001001da>] do_one_initcall+0xa2/0x1b8
>> [ 0.998666] [<0000000000d3ae52>] kernel_init_freeable+0x232/0x2e0
>> [ 0.998668] [<00000000008312d2>] kernel_init+0x2a/0x120
>> [ 0.998670] [<000000000083d332>] kernel_thread_starter+0x6/0xc
>> [ 0.998671] [<000000000083d32c>] kernel_thread_starter+0x0/0xc
>> [ 0.998673] no locks held by swapper/0/1.
>> [ 0.998673] Last Breaking-Event-Address:
>> [ 0.998675] [<0000000000582768>] kobject_get+0x68/0x90
>> [ 0.998678] ---[ end trace cae7490da7950580 ]---
>> [ 0.998679] Unable to handle kernel pointer dereference in virtual kernel address space
>> [ 0.998681] failing address: 0000000000000000 TEID: 0000000000000483
>> [ 0.998681] Fault in home space mode while using kernel ASCE.
>> [ 0.998684] AS:0000000000fb1007 R3:000000023ffcf007 S:000000023fff8000 P:000000000000003d
>> [ 0.998719] Oops: 0004 ilc:3 [#1] SMP DEBUG_PAGEALLOC
>> [ 0.998721] Modules linked in:
>> [ 0.998723] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 4.5.0-rc1 #174
>> [ 0.998725] task: 0000000232720000 ti: 000000023270c000 task.ti: 000000023270c000
>> [ 0.998726] Krnl PSW : 0704c00180000000 0000000000582734 (kobject_get+0x34/0x90)
>> [ 0.998729] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 EA:3
>> Krnl GPRS: 000000000000006c 0000000200000001 000000000000005c 0000000000000001
>> [ 0.998731] 0000000000287e04 0000000000000000 0000000000dd99a8 0000000000000000
>> [ 0.998733] 0000000000d86008 0000000000000000 0000000000000000 0000000000000000
>> [ 0.998734] 0000000000000010 0000000000000010 0000000000582768 000000023270fbb0
>> [ 0.998739] Krnl Code: 0000000000582728: 9180203c tm 60(%%r2),128
>> 000000000058272c: a7840013 brc 8,582752
>> #0000000000582730: a7180001 lhi %%r1,1
>> >0000000000582734: eb11d03800f8 laa %%r1,%%r1,56(%%r13)
>> 000000000058273a: 07e0 bcr 14,%%r0
>> 000000000058273c: a71a0001 ahi %%r1,1
>> 0000000000582740: ec1c0018017e cij %%r1,1,12,582770
>> 0000000000582746: b904002d lgr %%r2,%%r13
>> [ 0.998839] Call Trace:
>> [ 0.998841] ([<0000000000582768>] kobject_get+0x68/0x90)
>> [ 0.998843] [<000000000058318e>] kobject_add_internal+0x46/0x2e8
>> [ 0.998844] [<0000000000583684>] kobject_add+0x7c/0xd0
>> [ 0.998846] [<0000000000583722>] kobject_create_and_add+0x4a/0x98
>> [ 0.998847] [<00000000002e8ee0>] hugetlb_register_node+0x68/0x130
>> [ 0.998849] [<0000000000d59ef0>] hugetlb_init+0x4f0/0x600
>> [ 0.998850] [<00000000001001da>] do_one_initcall+0xa2/0x1b8
>> [ 0.998852] [<0000000000d3ae52>] kernel_init_freeable+0x232/0x2e0
>> [ 0.998853] [<00000000008312d2>] kernel_init+0x2a/0x120
>> [ 0.998855] [<000000000083d332>] kernel_thread_starter+0x6/0xc
>> [ 0.998856] [<000000000083d32c>] kernel_thread_starter+0x0/0xc
>> [ 0.998857] INFO: lockdep is turned off.
>> [ 0.998858] Last Breaking-Event-Address:
>> [ 0.998859] [<000000000058276c>] kobject_get+0x6c/0x90
>> [ 0.998861]
>> [ 0.998863] Kernel panic - not syncing: Fatal exception: panic_on_oops
>