* [v2 PATCH] mm: move page_ext_init after all struct pages are initialized
@ 2016-05-19 22:13 Yang Shi
2016-05-20 13:16 ` Michal Hocko
0 siblings, 1 reply; 6+ messages in thread
From: Yang Shi @ 2016-05-19 22:13 UTC (permalink / raw)
To: akpm, iamjoonsoo.kim; +Cc: linux-kernel, linux-mm, linaro-kernel, yang.shi
When DEFERRED_STRUCT_PAGE_INIT is enabled, just a subset of memmap at boot
are initialized, then the rest are initialized in parallel by starting one-off
"pgdatinitX" kernel thread for each node X.
If page_ext_init is called before it, some pages will not have valid extension,
this may lead the below kernel oops when booting up kernel:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0
PGD 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in:
CPU: 11 PID: 106 Comm: pgdatinit1 Not tainted 4.6.0-rc5-next-20160427 #26
Hardware name: Intel Corporation S5520HC/S5520HC, BIOS S5500.86B.01.10.0025.030220091519 03/02/2009
task: ffff88017c080040 ti: ffff88017c084000 task.ti: ffff88017c084000
RIP: 0010:[<ffffffff8118d982>] [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0
RSP: 0000:ffff88017c087c48 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000980 RSI: 0000000000000080 RDI: 0000000000660401
RBP: ffff88017c087cd0 R08: 0000000000000401 R09: 0000000000000009
R10: ffff88017c080040 R11: 000000000000000a R12: 0000000000000400
R13: ffffea0019810000 R14: ffffea0019810040 R15: ffff88066cfe6080
FS: 0000000000000000(0000) GS:ffff88066cd40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000002406000 CR4: 00000000000006e0
Stack:
ffff88066cd5bbd8 ffff88066cfe6640 0000000000000000 0000000000000000
0000001f0000001f ffff88066cd5bbe8 ffffea0019810000 000000008118f53e
0000000000000009 0000000000000401 ffffffff0000000a 0000000000000001
Call Trace:
[<ffffffff8118f602>] free_hot_cold_page+0x192/0x1d0
[<ffffffff8118f69c>] __free_pages+0x5c/0x90
[<ffffffff8262a676>] __free_pages_boot_core+0x11a/0x14e
[<ffffffff8262a6fa>] deferred_free_range+0x50/0x62
[<ffffffff8262aa46>] deferred_init_memmap+0x220/0x3c3
[<ffffffff8262a826>] ? setup_per_cpu_pageset+0x35/0x35
[<ffffffff8108b1f8>] kthread+0xf8/0x110
[<ffffffff81c1b732>] ret_from_fork+0x22/0x40
[<ffffffff8108b100>] ? kthread_create_on_node+0x200/0x200
Code: 49 89 d4 48 c1 e0 06 49 01 c5 e9 de fe ff ff 4c 89 f7 44 89 4d b8 4c 89 45 c0 44 89 5d c8 48 89 4d d0 e8 62 c7 07 00 48 8b 4d d0 <48> 8b 00 44 8b 5d c8 4c 8b 45 c0 44 8b 4d b8 a8 02 0f 84 05 ff
RIP [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0
RSP <ffff88017c087c48>
CR2: 0000000000000000
Move page_ext_init() after page_alloc_init_late() to make sure page extension
is setup for all pages.
CC: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Yang Shi <yang.shi@linaro.org>
---
Changelog v1 --> v2:
Added bug description in the commit log per Andrew's comment
init/main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/init/main.c b/init/main.c
index b3c6e36..2075faf 100644
--- a/init/main.c
+++ b/init/main.c
@@ -606,7 +606,6 @@ asmlinkage __visible void __init start_kernel(void)
initrd_start = 0;
}
#endif
- page_ext_init();
debug_objects_mem_init();
kmemleak_init();
setup_per_cpu_pageset();
@@ -1004,6 +1003,8 @@ static noinline void __init kernel_init_freeable(void)
sched_init_smp();
page_alloc_init_late();
+ /* Initialize page ext after all struct pages are initializaed */
+ page_ext_init();
do_basic_setup();
--
2.0.2
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^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [v2 PATCH] mm: move page_ext_init after all struct pages are initialized
2016-05-19 22:13 [v2 PATCH] mm: move page_ext_init after all struct pages are initialized Yang Shi
@ 2016-05-20 13:16 ` Michal Hocko
2016-05-20 15:41 ` Shi, Yang
0 siblings, 1 reply; 6+ messages in thread
From: Michal Hocko @ 2016-05-20 13:16 UTC (permalink / raw)
To: Yang Shi; +Cc: akpm, iamjoonsoo.kim, linux-kernel, linux-mm, linaro-kernel
On Thu 19-05-16 15:13:26, Yang Shi wrote:
[...]
> diff --git a/init/main.c b/init/main.c
> index b3c6e36..2075faf 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -606,7 +606,6 @@ asmlinkage __visible void __init start_kernel(void)
> initrd_start = 0;
> }
> #endif
> - page_ext_init();
> debug_objects_mem_init();
> kmemleak_init();
> setup_per_cpu_pageset();
> @@ -1004,6 +1003,8 @@ static noinline void __init kernel_init_freeable(void)
> sched_init_smp();
>
> page_alloc_init_late();
> + /* Initialize page ext after all struct pages are initializaed */
> + page_ext_init();
>
> do_basic_setup();
I might be missing something but don't we have the same problem with
CONFIG_FLATMEM? page_ext_init_flatmem is called way earlier. Or
CONFIG_DEFERRED_STRUCT_PAGE_INIT is never enabled for CONFIG_FLATMEM?
--
Michal Hocko
SUSE Labs
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* Re: [v2 PATCH] mm: move page_ext_init after all struct pages are initialized
2016-05-20 13:16 ` Michal Hocko
@ 2016-05-20 15:41 ` Shi, Yang
2016-05-23 7:31 ` Michal Hocko
0 siblings, 1 reply; 6+ messages in thread
From: Shi, Yang @ 2016-05-20 15:41 UTC (permalink / raw)
To: Michal Hocko; +Cc: akpm, iamjoonsoo.kim, linux-kernel, linux-mm, linaro-kernel
On 5/20/2016 6:16 AM, Michal Hocko wrote:
> On Thu 19-05-16 15:13:26, Yang Shi wrote:
> [...]
>> diff --git a/init/main.c b/init/main.c
>> index b3c6e36..2075faf 100644
>> --- a/init/main.c
>> +++ b/init/main.c
>> @@ -606,7 +606,6 @@ asmlinkage __visible void __init start_kernel(void)
>> initrd_start = 0;
>> }
>> #endif
>> - page_ext_init();
>> debug_objects_mem_init();
>> kmemleak_init();
>> setup_per_cpu_pageset();
>> @@ -1004,6 +1003,8 @@ static noinline void __init kernel_init_freeable(void)
>> sched_init_smp();
>>
>> page_alloc_init_late();
>> + /* Initialize page ext after all struct pages are initializaed */
>> + page_ext_init();
>>
>> do_basic_setup();
>
> I might be missing something but don't we have the same problem with
> CONFIG_FLATMEM? page_ext_init_flatmem is called way earlier. Or
> CONFIG_DEFERRED_STRUCT_PAGE_INIT is never enabled for CONFIG_FLATMEM?
Yes, CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on MEMORY_HOTPLUG which
depends on SPARSEMEM. So, this config is not valid for FLATMEM at all.
Thanks,
Yang
>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [v2 PATCH] mm: move page_ext_init after all struct pages are initialized
2016-05-20 15:41 ` Shi, Yang
@ 2016-05-23 7:31 ` Michal Hocko
2016-05-23 16:42 ` Shi, Yang
0 siblings, 1 reply; 6+ messages in thread
From: Michal Hocko @ 2016-05-23 7:31 UTC (permalink / raw)
To: Shi, Yang; +Cc: akpm, iamjoonsoo.kim, linux-kernel, linux-mm, linaro-kernel
On Fri 20-05-16 08:41:09, Shi, Yang wrote:
> On 5/20/2016 6:16 AM, Michal Hocko wrote:
> > On Thu 19-05-16 15:13:26, Yang Shi wrote:
> > [...]
> > > diff --git a/init/main.c b/init/main.c
> > > index b3c6e36..2075faf 100644
> > > --- a/init/main.c
> > > +++ b/init/main.c
> > > @@ -606,7 +606,6 @@ asmlinkage __visible void __init start_kernel(void)
> > > initrd_start = 0;
> > > }
> > > #endif
> > > - page_ext_init();
> > > debug_objects_mem_init();
> > > kmemleak_init();
> > > setup_per_cpu_pageset();
> > > @@ -1004,6 +1003,8 @@ static noinline void __init kernel_init_freeable(void)
> > > sched_init_smp();
> > >
> > > page_alloc_init_late();
> > > + /* Initialize page ext after all struct pages are initializaed */
> > > + page_ext_init();
> > >
> > > do_basic_setup();
> >
> > I might be missing something but don't we have the same problem with
> > CONFIG_FLATMEM? page_ext_init_flatmem is called way earlier. Or
> > CONFIG_DEFERRED_STRUCT_PAGE_INIT is never enabled for CONFIG_FLATMEM?
>
> Yes, CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on MEMORY_HOTPLUG which
> depends on SPARSEMEM. So, this config is not valid for FLATMEM at all.
Well
config MEMORY_HOTPLUG
bool "Allow for memory hot-add"
depends on SPARSEMEM || X86_64_ACPI_NUMA
depends on ARCH_ENABLE_MEMORY_HOTPLUG
I wasn't really sure about X86_64_ACPI_NUMA dependency branch which
depends on X86_64 && NUMA && ACPI && PCI and that didn't sound like
SPARSEMEM only. If the FLATMEM shouldn't exist with
CONFIG_DEFERRED_STRUCT_PAGE_INIT can we make that explicit please?
--
Michal Hocko
SUSE Labs
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [v2 PATCH] mm: move page_ext_init after all struct pages are initialized
2016-05-23 7:31 ` Michal Hocko
@ 2016-05-23 16:42 ` Shi, Yang
2016-05-23 18:04 ` Michal Hocko
0 siblings, 1 reply; 6+ messages in thread
From: Shi, Yang @ 2016-05-23 16:42 UTC (permalink / raw)
To: Michal Hocko; +Cc: akpm, iamjoonsoo.kim, linux-kernel, linux-mm, linaro-kernel
On 5/23/2016 12:31 AM, Michal Hocko wrote:
> On Fri 20-05-16 08:41:09, Shi, Yang wrote:
>> On 5/20/2016 6:16 AM, Michal Hocko wrote:
>>> On Thu 19-05-16 15:13:26, Yang Shi wrote:
>>> [...]
>>>> diff --git a/init/main.c b/init/main.c
>>>> index b3c6e36..2075faf 100644
>>>> --- a/init/main.c
>>>> +++ b/init/main.c
>>>> @@ -606,7 +606,6 @@ asmlinkage __visible void __init start_kernel(void)
>>>> initrd_start = 0;
>>>> }
>>>> #endif
>>>> - page_ext_init();
>>>> debug_objects_mem_init();
>>>> kmemleak_init();
>>>> setup_per_cpu_pageset();
>>>> @@ -1004,6 +1003,8 @@ static noinline void __init kernel_init_freeable(void)
>>>> sched_init_smp();
>>>>
>>>> page_alloc_init_late();
>>>> + /* Initialize page ext after all struct pages are initializaed */
>>>> + page_ext_init();
>>>>
>>>> do_basic_setup();
>>>
>>> I might be missing something but don't we have the same problem with
>>> CONFIG_FLATMEM? page_ext_init_flatmem is called way earlier. Or
>>> CONFIG_DEFERRED_STRUCT_PAGE_INIT is never enabled for CONFIG_FLATMEM?
>>
>> Yes, CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on MEMORY_HOTPLUG which
>> depends on SPARSEMEM. So, this config is not valid for FLATMEM at all.
>
> Well
> config MEMORY_HOTPLUG
> bool "Allow for memory hot-add"
> depends on SPARSEMEM || X86_64_ACPI_NUMA
> depends on ARCH_ENABLE_MEMORY_HOTPLUG
>
> I wasn't really sure about X86_64_ACPI_NUMA dependency branch which
> depends on X86_64 && NUMA && ACPI && PCI and that didn't sound like
> SPARSEMEM only. If the FLATMEM shouldn't exist with
Actually, FLATMEMT depends on !NUMA.
> CONFIG_DEFERRED_STRUCT_PAGE_INIT can we make that explicit please?
Sure, it makes the condition clearer and more readable.
Thanks,
Yang
>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [v2 PATCH] mm: move page_ext_init after all struct pages are initialized
2016-05-23 16:42 ` Shi, Yang
@ 2016-05-23 18:04 ` Michal Hocko
0 siblings, 0 replies; 6+ messages in thread
From: Michal Hocko @ 2016-05-23 18:04 UTC (permalink / raw)
To: Shi, Yang; +Cc: akpm, iamjoonsoo.kim, linux-kernel, linux-mm, linaro-kernel
On Mon 23-05-16 09:42:00, Shi, Yang wrote:
> On 5/23/2016 12:31 AM, Michal Hocko wrote:
> > On Fri 20-05-16 08:41:09, Shi, Yang wrote:
> > > On 5/20/2016 6:16 AM, Michal Hocko wrote:
> > > > On Thu 19-05-16 15:13:26, Yang Shi wrote:
> > > > [...]
> > > > > diff --git a/init/main.c b/init/main.c
> > > > > index b3c6e36..2075faf 100644
> > > > > --- a/init/main.c
> > > > > +++ b/init/main.c
> > > > > @@ -606,7 +606,6 @@ asmlinkage __visible void __init start_kernel(void)
> > > > > initrd_start = 0;
> > > > > }
> > > > > #endif
> > > > > - page_ext_init();
> > > > > debug_objects_mem_init();
> > > > > kmemleak_init();
> > > > > setup_per_cpu_pageset();
> > > > > @@ -1004,6 +1003,8 @@ static noinline void __init kernel_init_freeable(void)
> > > > > sched_init_smp();
> > > > >
> > > > > page_alloc_init_late();
> > > > > + /* Initialize page ext after all struct pages are initializaed */
> > > > > + page_ext_init();
> > > > >
> > > > > do_basic_setup();
> > > >
> > > > I might be missing something but don't we have the same problem with
> > > > CONFIG_FLATMEM? page_ext_init_flatmem is called way earlier. Or
> > > > CONFIG_DEFERRED_STRUCT_PAGE_INIT is never enabled for CONFIG_FLATMEM?
> > >
> > > Yes, CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on MEMORY_HOTPLUG which
> > > depends on SPARSEMEM. So, this config is not valid for FLATMEM at all.
> >
> > Well
> > config MEMORY_HOTPLUG
> > bool "Allow for memory hot-add"
> > depends on SPARSEMEM || X86_64_ACPI_NUMA
> > depends on ARCH_ENABLE_MEMORY_HOTPLUG
> >
> > I wasn't really sure about X86_64_ACPI_NUMA dependency branch which
> > depends on X86_64 && NUMA && ACPI && PCI and that didn't sound like
> > SPARSEMEM only. If the FLATMEM shouldn't exist with
>
> Actually, FLATMEMT depends on !NUMA.
Ahh, OK, you are right! Thanks for the clarification.
--
Michal Hocko
SUSE Labs
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2016-05-19 22:13 [v2 PATCH] mm: move page_ext_init after all struct pages are initialized Yang Shi
2016-05-20 13:16 ` Michal Hocko
2016-05-20 15:41 ` Shi, Yang
2016-05-23 7:31 ` Michal Hocko
2016-05-23 16:42 ` Shi, Yang
2016-05-23 18:04 ` Michal Hocko
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