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* Lockdep warning with init_espfix_ap()
@ 2014-10-09 15:35 Prarit Bhargava
  2014-10-15 15:57 ` H. Peter Anvin
  0 siblings, 1 reply; 4+ messages in thread
From: Prarit Bhargava @ 2014-10-09 15:35 UTC (permalink / raw)
  To: linux-kernel; +Cc: x86


Non-fatal warning seen with latest kernel tree during kernel boot.

 WARNING: CPU: 64 PID: 0 at kernel/locking/lockdep.c:2744
lockdep_trace_alloc+0xdd/0xe0()
 DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
 Modules linked in:

 CPU: 64 PID: 0 Comm: swapper/64 Not tainted 3.17.0+ #10
 Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS
BIVTSDP1.86B.0049.R00.1403081207 03/08/2014
  0000000000000000 d27b9ea0e3821f35 ffff88084edc3ce0 ffffffff8171cbd8
  ffff88084edc3d28 ffff88084edc3d18 ffffffff8108424d 0000000000000046
  0000000000000000 00000000000000d0 0000000000000002 0000000000000000
 Call Trace:
  [<ffffffff8171cbd8>] dump_stack+0x4d/0x66
  [<ffffffff8108424d>] warn_slowpath_common+0x7d/0xa0
  [<ffffffff810842cc>] warn_slowpath_fmt+0x5c/0x80
  [<ffffffff810e3e2d>] lockdep_trace_alloc+0xdd/0xe0
  [<ffffffff811c0aaf>] __alloc_pages_nodemask+0x9f/0x4b0
  [<ffffffff81025365>] ? native_sched_clock+0x35/0xa0
  [<ffffffff810253d9>] ? sched_clock+0x9/0x10
  [<ffffffff8120981a>] alloc_page_interleave+0x3a/0x90
  [<ffffffff8120ae8d>] alloc_pages_current+0x17d/0x1f0
  [<ffffffff811bab24>] ? __get_free_pages+0x14/0x50
  [<ffffffff811bab24>] __get_free_pages+0x14/0x50
  [<ffffffff8102225d>] init_espfix_ap+0x17d/0x320
  [<ffffffff8105254e>] start_secondary+0x19e/0x350
 ---[ end trace 2b62d796aa7ae001 ]---

 Debugging ... but sorta hoping someone else may have already seen it ;)

 P.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Lockdep warning with init_espfix_ap()
  2014-10-09 15:35 Lockdep warning with init_espfix_ap() Prarit Bhargava
@ 2014-10-15 15:57 ` H. Peter Anvin
  2014-10-15 16:03   ` Prarit Bhargava
  0 siblings, 1 reply; 4+ messages in thread
From: H. Peter Anvin @ 2014-10-15 15:57 UTC (permalink / raw)
  To: Prarit Bhargava, linux-kernel; +Cc: x86

On 10/09/2014 08:35 AM, Prarit Bhargava wrote:
> 
> Non-fatal warning seen with latest kernel tree during kernel boot.
> 
>  WARNING: CPU: 64 PID: 0 at kernel/locking/lockdep.c:2744
> lockdep_trace_alloc+0xdd/0xe0()
>  DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
>  Modules linked in:
> 
>  CPU: 64 PID: 0 Comm: swapper/64 Not tainted 3.17.0+ #10
>  Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS
> BIVTSDP1.86B.0049.R00.1403081207 03/08/2014
>   0000000000000000 d27b9ea0e3821f35 ffff88084edc3ce0 ffffffff8171cbd8
>   ffff88084edc3d28 ffff88084edc3d18 ffffffff8108424d 0000000000000046
>   0000000000000000 00000000000000d0 0000000000000002 0000000000000000
>  Call Trace:
>   [<ffffffff8171cbd8>] dump_stack+0x4d/0x66
>   [<ffffffff8108424d>] warn_slowpath_common+0x7d/0xa0
>   [<ffffffff810842cc>] warn_slowpath_fmt+0x5c/0x80
>   [<ffffffff810e3e2d>] lockdep_trace_alloc+0xdd/0xe0
>   [<ffffffff811c0aaf>] __alloc_pages_nodemask+0x9f/0x4b0
>   [<ffffffff81025365>] ? native_sched_clock+0x35/0xa0
>   [<ffffffff810253d9>] ? sched_clock+0x9/0x10
>   [<ffffffff8120981a>] alloc_page_interleave+0x3a/0x90
>   [<ffffffff8120ae8d>] alloc_pages_current+0x17d/0x1f0
>   [<ffffffff811bab24>] ? __get_free_pages+0x14/0x50
>   [<ffffffff811bab24>] __get_free_pages+0x14/0x50
>   [<ffffffff8102225d>] init_espfix_ap+0x17d/0x320
>   [<ffffffff8105254e>] start_secondary+0x19e/0x350
>  ---[ end trace 2b62d796aa7ae001 ]---
> 
>  Debugging ... but sorta hoping someone else may have already seen it ;)
> 

It is kind of a messy situation, because this code needs to allocate
memory but is run before the secondary CPU is fully up.  As such, it is
a false positive, at least in some ways.

	-hpa



^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Lockdep warning with init_espfix_ap()
  2014-10-15 15:57 ` H. Peter Anvin
@ 2014-10-15 16:03   ` Prarit Bhargava
  2014-10-15 16:05     ` H. Peter Anvin
  0 siblings, 1 reply; 4+ messages in thread
From: Prarit Bhargava @ 2014-10-15 16:03 UTC (permalink / raw)
  To: H. Peter Anvin; +Cc: linux-kernel, x86



On 10/15/2014 11:57 AM, H. Peter Anvin wrote:
> On 10/09/2014 08:35 AM, Prarit Bhargava wrote:
>>
>> Non-fatal warning seen with latest kernel tree during kernel boot.
>>
>>  WARNING: CPU: 64 PID: 0 at kernel/locking/lockdep.c:2744
>> lockdep_trace_alloc+0xdd/0xe0()
>>  DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
>>  Modules linked in:
>>
>>  CPU: 64 PID: 0 Comm: swapper/64 Not tainted 3.17.0+ #10
>>  Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS
>> BIVTSDP1.86B.0049.R00.1403081207 03/08/2014
>>   0000000000000000 d27b9ea0e3821f35 ffff88084edc3ce0 ffffffff8171cbd8
>>   ffff88084edc3d28 ffff88084edc3d18 ffffffff8108424d 0000000000000046
>>   0000000000000000 00000000000000d0 0000000000000002 0000000000000000
>>  Call Trace:
>>   [<ffffffff8171cbd8>] dump_stack+0x4d/0x66
>>   [<ffffffff8108424d>] warn_slowpath_common+0x7d/0xa0
>>   [<ffffffff810842cc>] warn_slowpath_fmt+0x5c/0x80
>>   [<ffffffff810e3e2d>] lockdep_trace_alloc+0xdd/0xe0
>>   [<ffffffff811c0aaf>] __alloc_pages_nodemask+0x9f/0x4b0
>>   [<ffffffff81025365>] ? native_sched_clock+0x35/0xa0
>>   [<ffffffff810253d9>] ? sched_clock+0x9/0x10
>>   [<ffffffff8120981a>] alloc_page_interleave+0x3a/0x90
>>   [<ffffffff8120ae8d>] alloc_pages_current+0x17d/0x1f0
>>   [<ffffffff811bab24>] ? __get_free_pages+0x14/0x50
>>   [<ffffffff811bab24>] __get_free_pages+0x14/0x50
>>   [<ffffffff8102225d>] init_espfix_ap+0x17d/0x320
>>   [<ffffffff8105254e>] start_secondary+0x19e/0x350
>>  ---[ end trace 2b62d796aa7ae001 ]---
>>
>>  Debugging ... but sorta hoping someone else may have already seen it ;)
>>
> 
> It is kind of a messy situation, because this code needs to allocate
> memory but is run before the secondary CPU is fully up.  As such, it is
> a false positive, at least in some ways.

Interesting -- FWIW, I can reproduce this 100% of the time on _one_ system.  It
isn't a big deal and likely just worth noting at this point.  I *always* see it
when bringing up CPU 64 (of 128).

P.

> 
> 	-hpa
> 
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Lockdep warning with init_espfix_ap()
  2014-10-15 16:03   ` Prarit Bhargava
@ 2014-10-15 16:05     ` H. Peter Anvin
  0 siblings, 0 replies; 4+ messages in thread
From: H. Peter Anvin @ 2014-10-15 16:05 UTC (permalink / raw)
  To: Prarit Bhargava; +Cc: linux-kernel, x86

On 10/15/2014 09:03 AM, Prarit Bhargava wrote:
>>
>> It is kind of a messy situation, because this code needs to allocate
>> memory but is run before the secondary CPU is fully up.  As such, it is
>> a false positive, at least in some ways.
> 
> Interesting -- FWIW, I can reproduce this 100% of the time on _one_ system.  It
> isn't a big deal and likely just worth noting at this point.  I *always* see it
> when bringing up CPU 64 (of 128).
> 

... because that is the first CPU which needs to allocate memory.

	-hpa



^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2014-10-15 16:05 UTC | newest]

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2014-10-09 15:35 Lockdep warning with init_espfix_ap() Prarit Bhargava
2014-10-15 15:57 ` H. Peter Anvin
2014-10-15 16:03   ` Prarit Bhargava
2014-10-15 16:05     ` H. Peter Anvin

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