linux-kernel - Re: Regression: 4.5-rc1 (bisect: hugetlb: make mm and fs code explicitly non-modular vs CONFIG_TIMER

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Message-ID: <56A9E404.7000409@de.ibm.com>
Date:	Thu, 28 Jan 2016 10:48:52 +0100
From:	Christian Borntraeger <borntraeger@...ibm.com>
To:	Hillf Danton <hillf.zj@...baba-inc.com>,
	"'Paul Gortmaker'" <paul.gortmaker@...driver.com>
Cc:	"'Andrew Morton'" <akpm@...ux-foundation.org>,
	"'Nadia Yvette Chambers'" <nyc@...omorphy.com>,
	"'Alexander Viro'" <viro@...iv.linux.org.uk>,
	"'Naoya Horiguchi'" <n-horiguchi@...jp.nec.com>,
	"'Mike Kravetz'" <mike.kravetz@...cle.com>,
	"'David Rientjes'" <rientjes@...gle.com>,
	"'Davidlohr Bueso'" <dave@...olabs.net>,
	"'Linux Kernel Mailing List'" <linux-kernel@...r.kernel.org>
Subject: Re: Regression: 4.5-rc1 (bisect: hugetlb: make mm and fs code
 explicitly non-modular vs CONFIG_TIMER_STATS)

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
>