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

[Christian Borntraeger]

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. 
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