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* swap_info_get: Bad swap offset entry 0200f8a7
@ 2017-10-16  0:17 Christian Kujau
  2017-10-20  0:33   ` Minchan Kim
  2017-10-20 11:31 ` huang ying
  0 siblings, 2 replies; 6+ messages in thread
From: Christian Kujau @ 2017-10-16  0:17 UTC (permalink / raw)
  To: linux-kernel; +Cc: Hugh Dickins, Minchan Kim, Nitin Gupta, Robert Schelander

Hi,

every now and then (and more frequently now) I receive the following 
message on this Atom N270 netbook:

  swap_info_get: Bad swap offset entry 0200f8a7

This started to show up a few months ago but appears to happen more 
frequently now:

      4 May  < Linux version 4.11.2-1-ARCH
      4 Jun  < Linux version 4.11.3-1-ARCH
      7 Jul  < Linux version 4.11.9-1-ARCH
      4 Aug  < Linux version 4.12.8-2-ARCH
     24 Sep  < Linux version 4.12.13-1-ARCH
    158 Oct  < Linux version 4.13.5-1-ARCH

I've only found (very) old reports for this[0][2] with either no 
solution[1] or some hinting that this may be caused by hardware errors.

In my case howerver no kernel BUG messages or oopses are involved and no
PTE errors are logged. The machine appears to be very stable, although
memory usage is quite high on that machine (but no OOM situations so
far either). As the machine is only equipped with 1GB of RAM, I'm
using ZRAM on this system, which usually looks something like this:

  $ zramctl 
  NAME       ALGORITHM DISKSIZE   DATA COMPR TOTAL STREAMS MOUNTPOINT
  /dev/zram0 lz4         248.7M 195.7M   74M 78.7M       2 [SWAP]

I suspect that, when memory pressure is high, zram may not be quick enough 
to decompress a page leading to these messages, but then I'd have expected 
a zram error message too.

Can anybody comment on these messages? If they're really indicating a 
hardware error, shouldn't there be other messages too? So far, rasdaemon 
has not logged any errors.

Thanks,
Christian.

[0] http://lkml.iu.edu/hypermail/linux/kernel/0204.3/0165.html
[1] https://bugzilla.redhat.com/show_bug.cgi?id=432337
[2] https://access.redhat.com/solutions/218733
-- 
BOFH excuse #323:

Your processor has processed too many instructions.  Turn it off immediately, do not type any commands!!

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: swap_info_get: Bad swap offset entry 0200f8a7
  2017-10-16  0:17 swap_info_get: Bad swap offset entry 0200f8a7 Christian Kujau
@ 2017-10-20  0:33   ` Minchan Kim
  2017-10-20 11:31 ` huang ying
  1 sibling, 0 replies; 6+ messages in thread
From: Minchan Kim @ 2017-10-20  0:33 UTC (permalink / raw)
  To: Christian Kujau
  Cc: linux-kernel, Hugh Dickins, Nitin Gupta, Robert Schelander,
	Andrew Morton, linux-mm, Huang, Ying

Hello,

On Sun, Oct 15, 2017 at 05:17:36PM -0700, Christian Kujau wrote:
> Hi,
> 
> every now and then (and more frequently now) I receive the following 
> message on this Atom N270 netbook:
> 
>   swap_info_get: Bad swap offset entry 0200f8a7
> 
> This started to show up a few months ago but appears to happen more 
> frequently now:
> 
>       4 May  < Linux version 4.11.2-1-ARCH
>       4 Jun  < Linux version 4.11.3-1-ARCH
>       7 Jul  < Linux version 4.11.9-1-ARCH
>       4 Aug  < Linux version 4.12.8-2-ARCH
>      24 Sep  < Linux version 4.12.13-1-ARCH
>     158 Oct  < Linux version 4.13.5-1-ARCH
> 
> I've only found (very) old reports for this[0][2] with either no 
> solution[1] or some hinting that this may be caused by hardware errors.

Since 4.11, there are lots of happenings in swap subsystem to be optimized
so it might be related to one of those changes but I'm not sure.
Worth to Ccing Huang who may know somethings since then.

Thanks.

> 
> In my case howerver no kernel BUG messages or oopses are involved and no
> PTE errors are logged. The machine appears to be very stable, although
> memory usage is quite high on that machine (but no OOM situations so
> far either). As the machine is only equipped with 1GB of RAM, I'm
> using ZRAM on this system, which usually looks something like this:
> 
>   $ zramctl 
>   NAME       ALGORITHM DISKSIZE   DATA COMPR TOTAL STREAMS MOUNTPOINT
>   /dev/zram0 lz4         248.7M 195.7M   74M 78.7M       2 [SWAP]
> 
> I suspect that, when memory pressure is high, zram may not be quick enough 
> to decompress a page leading to these messages, but then I'd have expected 
> a zram error message too.
> 
> Can anybody comment on these messages? If they're really indicating a 
> hardware error, shouldn't there be other messages too? So far, rasdaemon 
> has not logged any errors.
> 
> Thanks,
> Christian.
> 
> [0] http://lkml.iu.edu/hypermail/linux/kernel/0204.3/0165.html
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=432337
> [2] https://access.redhat.com/solutions/218733
> -- 
> BOFH excuse #323:
> 
> Your processor has processed too many instructions.  Turn it off immediately, do not type any commands!!

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: swap_info_get: Bad swap offset entry 0200f8a7
@ 2017-10-20  0:33   ` Minchan Kim
  0 siblings, 0 replies; 6+ messages in thread
From: Minchan Kim @ 2017-10-20  0:33 UTC (permalink / raw)
  To: Christian Kujau
  Cc: linux-kernel, Hugh Dickins, Nitin Gupta, Robert Schelander,
	Andrew Morton, linux-mm, Huang, Ying

Hello,

On Sun, Oct 15, 2017 at 05:17:36PM -0700, Christian Kujau wrote:
> Hi,
> 
> every now and then (and more frequently now) I receive the following 
> message on this Atom N270 netbook:
> 
>   swap_info_get: Bad swap offset entry 0200f8a7
> 
> This started to show up a few months ago but appears to happen more 
> frequently now:
> 
>       4 May  < Linux version 4.11.2-1-ARCH
>       4 Jun  < Linux version 4.11.3-1-ARCH
>       7 Jul  < Linux version 4.11.9-1-ARCH
>       4 Aug  < Linux version 4.12.8-2-ARCH
>      24 Sep  < Linux version 4.12.13-1-ARCH
>     158 Oct  < Linux version 4.13.5-1-ARCH
> 
> I've only found (very) old reports for this[0][2] with either no 
> solution[1] or some hinting that this may be caused by hardware errors.

Since 4.11, there are lots of happenings in swap subsystem to be optimized
so it might be related to one of those changes but I'm not sure.
Worth to Ccing Huang who may know somethings since then.

Thanks.

> 
> In my case howerver no kernel BUG messages or oopses are involved and no
> PTE errors are logged. The machine appears to be very stable, although
> memory usage is quite high on that machine (but no OOM situations so
> far either). As the machine is only equipped with 1GB of RAM, I'm
> using ZRAM on this system, which usually looks something like this:
> 
>   $ zramctl 
>   NAME       ALGORITHM DISKSIZE   DATA COMPR TOTAL STREAMS MOUNTPOINT
>   /dev/zram0 lz4         248.7M 195.7M   74M 78.7M       2 [SWAP]
> 
> I suspect that, when memory pressure is high, zram may not be quick enough 
> to decompress a page leading to these messages, but then I'd have expected 
> a zram error message too.
> 
> Can anybody comment on these messages? If they're really indicating a 
> hardware error, shouldn't there be other messages too? So far, rasdaemon 
> has not logged any errors.
> 
> Thanks,
> Christian.
> 
> [0] http://lkml.iu.edu/hypermail/linux/kernel/0204.3/0165.html
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=432337
> [2] https://access.redhat.com/solutions/218733
> -- 
> BOFH excuse #323:
> 
> Your processor has processed too many instructions.  Turn it off immediately, do not type any commands!!

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: swap_info_get: Bad swap offset entry 0200f8a7
  2017-10-16  0:17 swap_info_get: Bad swap offset entry 0200f8a7 Christian Kujau
  2017-10-20  0:33   ` Minchan Kim
@ 2017-10-20 11:31 ` huang ying
  2017-10-21  1:07   ` Christian Kujau
  1 sibling, 1 reply; 6+ messages in thread
From: huang ying @ 2017-10-20 11:31 UTC (permalink / raw)
  To: Christian Kujau
  Cc: LKML, Hugh Dickins, Minchan Kim, Nitin Gupta, Robert Schelander

Hi, Christian,

On Mon, Oct 16, 2017 at 8:17 AM, Christian Kujau <lists@nerdbynature.de> wrote:
> Hi,
>
> every now and then (and more frequently now) I receive the following
> message on this Atom N270 netbook:
>
>   swap_info_get: Bad swap offset entry 0200f8a7
>
> This started to show up a few months ago but appears to happen more
> frequently now:
>
>       4 May  < Linux version 4.11.2-1-ARCH
>       4 Jun  < Linux version 4.11.3-1-ARCH
>       7 Jul  < Linux version 4.11.9-1-ARCH
>       4 Aug  < Linux version 4.12.8-2-ARCH
>      24 Sep  < Linux version 4.12.13-1-ARCH
>     158 Oct  < Linux version 4.13.5-1-ARCH

So you have never seen this before 4.11 like 4.10?  Which operations
will trigger this error messages?  Is it possible for you to check
whether the error exists for normal swap device (not ZRAM)?  32bit or
64bit kernel do you use?

Best Regards,
Huang, Ying

> I've only found (very) old reports for this[0][2] with either no
> solution[1] or some hinting that this may be caused by hardware errors.
>
> In my case howerver no kernel BUG messages or oopses are involved and no
> PTE errors are logged. The machine appears to be very stable, although
> memory usage is quite high on that machine (but no OOM situations so
> far either). As the machine is only equipped with 1GB of RAM, I'm
> using ZRAM on this system, which usually looks something like this:
>
>   $ zramctl
>   NAME       ALGORITHM DISKSIZE   DATA COMPR TOTAL STREAMS MOUNTPOINT
>   /dev/zram0 lz4         248.7M 195.7M   74M 78.7M       2 [SWAP]
>
> I suspect that, when memory pressure is high, zram may not be quick enough
> to decompress a page leading to these messages, but then I'd have expected
> a zram error message too.
>
> Can anybody comment on these messages? If they're really indicating a
> hardware error, shouldn't there be other messages too? So far, rasdaemon
> has not logged any errors.
>
> Thanks,
> Christian.
>
> [0] http://lkml.iu.edu/hypermail/linux/kernel/0204.3/0165.html
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=432337
> [2] https://access.redhat.com/solutions/218733
> --
> BOFH excuse #323:
>
> Your processor has processed too many instructions.  Turn it off immediately, do not type any commands!!

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: swap_info_get: Bad swap offset entry 0200f8a7
  2017-10-20 11:31 ` huang ying
@ 2017-10-21  1:07   ` Christian Kujau
  2017-10-21 16:07     ` huang ying
  0 siblings, 1 reply; 6+ messages in thread
From: Christian Kujau @ 2017-10-21  1:07 UTC (permalink / raw)
  To: huang ying
  Cc: LKML, Hugh Dickins, Minchan Kim, Nitin Gupta, Robert Schelander

On Fri, 20 Oct 2017, huang ying wrote:
> >       4 May  < Linux version 4.11.2-1-ARCH
> >       4 Jun  < Linux version 4.11.3-1-ARCH
> >       7 Jul  < Linux version 4.11.9-1-ARCH
> >       4 Aug  < Linux version 4.12.8-2-ARCH
> >      24 Sep  < Linux version 4.12.13-1-ARCH
> >     158 Oct  < Linux version 4.13.5-1-ARCH
> 
> So you have never seen this before 4.11 like 4.10?

Unfortunately the kernel logs for that machine only go back until May 
2017 and I cannot tell if that hasn't happened before. I've seen these 
messages appear since then but didn't bother much. But as it now happens 
more frequently, I thought I should mention this to the list.

> Which operations will trigger this error messages?

I'm not able to reproduce it at will, but I suspect that memory pressure 
triggers these messages. The machine in question is an Lenovo Ideapad S10 
notebook running 24x7 and is equipped with 1 GB of RAM. Two Java processes 
are basically using up all the memory, so usually it tooks like this:

========================================
$ free -m
       total   used  free   shared  buff/cache available
Mem:     994    866    67       1           60        20
Swap:    760    437   322

$ zramctl 
NAME       ALGORITHM DISKSIZE  DATA COMPR TOTAL STREAMS MOUNTPOINT
/dev/zram0 lz4         248.7M  247M 92.3M 97.4M       2 [SWAP]
========================================

I just assumed the message is triggered when the system is really low on 
memory and maybe zram is too slow to provide the memory requested. But 
that's just my layman's assumption :-) For example, today's message was 
emitted during the night:


Oct 20 01:26:18 len kernel: [638973.207849] \
   swap_info_get: Bad swap offset entry 0200f8a7


And here are the sysstat numbers for that time frame:


$ sar -r -s 00:00 -e 02:00
Linux 4.13.5-1-ARCH (len)       10/20/2017      _i686_  (2 CPU)
12:00:01 AM kbmemfree kbmemused  %memused kbbuffers  kbcached  kbcommit   %commit  kbactive   kbinact   kbdirty
12:10:06 AM     70076    948404     93.12         4     19004   1556176     86.58    376608    379408       220
12:20:02 AM     80488    937992     92.10         4    180404   1563952     87.01    380184    327736      5568
12:30:03 AM     83296    935184     91.82         4    137260   1569776     87.34    329512    330000       280
12:40:03 AM     65188    953292     93.60         4     21156   1571048     87.41    386644    389820      1144
12:50:03 AM     67512    950968     93.37         4     33452   1570628     87.38    378936    381580      1304
01:00:07 AM     65520    952960     93.57         4     24996   1573180     87.53    385396    386152       904
01:10:03 AM     66956    951524     93.43         4     35520   1572696     87.50    379548    379364       172
01:20:02 AM     67440    951040     93.38         4     88736   1569864     87.34    381764    370472      7080
01:30:03 AM     70048    948432     93.12         4     29212   1572504     87.49    383516    381900      1832
01:40:04 AM     71532    946948     92.98         4     29220   1570096     87.35    380120    380284      1000
01:50:03 AM     65828    952652     93.54         4     34408   1570604     87.38    381040    381028      1604
Average:        70353    948127     93.09         4     57579   1569139     87.30    376661    371613      1919


 == If that is unreadable, here it is again: https://paste.debian.net/991927/

> Is it possible for you to check
> whether the error exists for normal swap device (not ZRAM)?

I have "normal" (but encrpted) swap configured but with a lower priority:

cat /proc/swaps 
Filename        Type            Size    Used    Priority
/dev/dm-0       partition       524284  194348  0
/dev/zram0      partition       254616  253536  32767

I shall disable the zram device and disable encryption too and will report 
back if the message appears again.

> 32bit or 64bit kernel do you use?

I'm using an i686 kernel for this Atom N270 processor (with HT enabled).

Thanks for your response,
Christian.
-- 
BOFH excuse #403:

Sysadmin didn't hear pager go off due to loud music from bar-room speakers.

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: swap_info_get: Bad swap offset entry 0200f8a7
  2017-10-21  1:07   ` Christian Kujau
@ 2017-10-21 16:07     ` huang ying
  0 siblings, 0 replies; 6+ messages in thread
From: huang ying @ 2017-10-21 16:07 UTC (permalink / raw)
  To: Christian Kujau
  Cc: LKML, Hugh Dickins, Minchan Kim, Nitin Gupta, Robert Schelander

On Sat, Oct 21, 2017 at 9:07 AM, Christian Kujau <lists@nerdbynature.de> wrote:
> On Fri, 20 Oct 2017, huang ying wrote:
>> >       4 May  < Linux version 4.11.2-1-ARCH
>> >       4 Jun  < Linux version 4.11.3-1-ARCH
>> >       7 Jul  < Linux version 4.11.9-1-ARCH
>> >       4 Aug  < Linux version 4.12.8-2-ARCH
>> >      24 Sep  < Linux version 4.12.13-1-ARCH
>> >     158 Oct  < Linux version 4.13.5-1-ARCH
>>
>> So you have never seen this before 4.11 like 4.10?
>
> Unfortunately the kernel logs for that machine only go back until May
> 2017 and I cannot tell if that hasn't happened before. I've seen these
> messages appear since then but didn't bother much. But as it now happens
> more frequently, I thought I should mention this to the list.
>
>> Which operations will trigger this error messages?
>
> I'm not able to reproduce it at will, but I suspect that memory pressure
> triggers these messages. The machine in question is an Lenovo Ideapad S10
> notebook running 24x7 and is equipped with 1 GB of RAM. Two Java processes
> are basically using up all the memory, so usually it tooks like this:
>
> ========================================
> $ free -m
>        total   used  free   shared  buff/cache available
> Mem:     994    866    67       1           60        20
> Swap:    760    437   322
>
> $ zramctl
> NAME       ALGORITHM DISKSIZE  DATA COMPR TOTAL STREAMS MOUNTPOINT
> /dev/zram0 lz4         248.7M  247M 92.3M 97.4M       2 [SWAP]
> ========================================
>
> I just assumed the message is triggered when the system is really low on
> memory and maybe zram is too slow to provide the memory requested. But
> that's just my layman's assumption :-) For example, today's message was
> emitted during the night:
>
>
> Oct 20 01:26:18 len kernel: [638973.207849] \
>    swap_info_get: Bad swap offset entry 0200f8a7
>
>
> And here are the sysstat numbers for that time frame:
>
>
> $ sar -r -s 00:00 -e 02:00
> Linux 4.13.5-1-ARCH (len)       10/20/2017      _i686_  (2 CPU)
> 12:00:01 AM kbmemfree kbmemused  %memused kbbuffers  kbcached  kbcommit   %commit  kbactive   kbinact   kbdirty
> 12:10:06 AM     70076    948404     93.12         4     19004   1556176     86.58    376608    379408       220
> 12:20:02 AM     80488    937992     92.10         4    180404   1563952     87.01    380184    327736      5568
> 12:30:03 AM     83296    935184     91.82         4    137260   1569776     87.34    329512    330000       280
> 12:40:03 AM     65188    953292     93.60         4     21156   1571048     87.41    386644    389820      1144
> 12:50:03 AM     67512    950968     93.37         4     33452   1570628     87.38    378936    381580      1304
> 01:00:07 AM     65520    952960     93.57         4     24996   1573180     87.53    385396    386152       904
> 01:10:03 AM     66956    951524     93.43         4     35520   1572696     87.50    379548    379364       172
> 01:20:02 AM     67440    951040     93.38         4     88736   1569864     87.34    381764    370472      7080
> 01:30:03 AM     70048    948432     93.12         4     29212   1572504     87.49    383516    381900      1832
> 01:40:04 AM     71532    946948     92.98         4     29220   1570096     87.35    380120    380284      1000
> 01:50:03 AM     65828    952652     93.54         4     34408   1570604     87.38    381040    381028      1604
> Average:        70353    948127     93.09         4     57579   1569139     87.30    376661    371613      1919
>
>
>  == If that is unreadable, here it is again: https://paste.debian.net/991927/
>
>> Is it possible for you to check
>> whether the error exists for normal swap device (not ZRAM)?
>
> I have "normal" (but encrpted) swap configured but with a lower priority:
>
> cat /proc/swaps
> Filename        Type            Size    Used    Priority
> /dev/dm-0       partition       524284  194348  0
> /dev/zram0      partition       254616  253536  32767
>
> I shall disable the zram device and disable encryption too and will report
> back if the message appears again.
>
>> 32bit or 64bit kernel do you use?
>
> I'm using an i686 kernel for this Atom N270 processor (with HT enabled).

Thanks for your information!  I have reproduced your problem.  They
are just false error message.  I will fix that and send out the patch
soon.

Best Regards,
Huang, Ying

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-10-21 16:08 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-10-16  0:17 swap_info_get: Bad swap offset entry 0200f8a7 Christian Kujau
2017-10-20  0:33 ` Minchan Kim
2017-10-20  0:33   ` Minchan Kim
2017-10-20 11:31 ` huang ying
2017-10-21  1:07   ` Christian Kujau
2017-10-21 16:07     ` huang ying

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