[Powertop] (BUG) powertop-1.13 fails to kernel-3.10.7

[Powertop] (BUG) powertop-1.13 fails to kernel-3.10.7

[Dennis Jenkins]

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Hello,

   I recently updated my Gentoo linux kernel from 3.8.18 to 3.10.7.
powertop now hangs while starting up.  "strace" shows that powertop is
reading the contents of "/proc/timer_list" over and over (but with no
"seek" call, which is weird to me).

ostara ~ # powertop --version
powertop version 1.13

ostara ~ # uname -r
3.10.7-gentoo

ostara ~ # zgrep TIMER /proc/config.gz
CONFIG_HIGH_RES_TIMERS=y
CONFIG_TIMERFD=y
CONFIG_OPROFILE_NMI_TIMER=y
CONFIG_HPET_TIMER=y
# CONFIG_X86_PM_TIMER is not set
CONFIG_NETFILTER_XT_TARGET_IDLETIMER=m
# CONFIG_HW_RANDOM_TIMERIOMEM is not set
# CONFIG_HANGCHECK_TIMER is not set
# CONFIG_PPS_CLIENT_KTIMER is not set
CONFIG_SND_TIMER=m
# CONFIG_SND_HRTIMER is not set
CONFIG_TIMER_STATS=y

ostara ~ # wc /proc/timer_list
387 1569 16282 /proc/timer_list


ostara ~ # strace -e\!read powertop
(tailing...)
open("/proc/interrupts", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x7fcfdd7c3000
open("/proc/timer_list", O_RDONLY)      = 4
fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x7fcfdd7c2000
^CProcess 22238 detached

Now run "strace" again, but without the "-e\!read" and watch it read fd #4
over and over and over again.

If you need any additional info, please let me know.

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Re: [Powertop] (BUG) powertop-1.13 fails to kernel-3.10.7

[Sergey Senozhatsky]

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On (08/24/13 09:35), Dennis Jenkins wrote:
>    Hello,
> 
>    �� I recently updated my Gentoo linux kernel from 3.8.18 to 3.10.7.�
>    powertop now hangs while starting up.� "strace" shows that powertop is
>    reading the contents of "/proc/timer_list" over and over (but with no�
>    "seek" call, which is weird to me).

Hello,
sorry for long response. this one really looks like a kernel bug
fixed by 84a78a6504f5c5394a8e558702e5b54131f01d14 upstream (3.11)

	-ss

>    ostara ~ # powertop --version
>    powertop version 1.13
> 
>    ostara ~ # uname -r
>    3.10.7-gentoo
> 
>    ostara ~ # zgrep TIMER /proc/config.gz
>    CONFIG_HIGH_RES_TIMERS=y
>    CONFIG_TIMERFD=y
>    CONFIG_OPROFILE_NMI_TIMER=y
>    CONFIG_HPET_TIMER=y
>    # CONFIG_X86_PM_TIMER is not set
>    CONFIG_NETFILTER_XT_TARGET_IDLETIMER=m
>    # CONFIG_HW_RANDOM_TIMERIOMEM is not set
>    # CONFIG_HANGCHECK_TIMER is not set
>    # CONFIG_PPS_CLIENT_KTIMER is not set
>    CONFIG_SND_TIMER=m
>    # CONFIG_SND_HRTIMER is not set
>    CONFIG_TIMER_STATS=y
> 
>    ostara ~ # wc /proc/timer_list
>    387 1569 16282 /proc/timer_list
> 
>    ostara ~ # strace -e\!read powertop
>    (tailing...)
>    open("/proc/interrupts", O_RDONLY)����� = 3
>    fstat(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
>    mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
>    0x7fcfdd7c3000
>    open("/proc/timer_list", O_RDONLY)����� = 4
>    fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
>    mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
>    0x7fcfdd7c2000
>    ^CProcess 22238 detached
> 
>    Now run "strace" again, but without the "-e\!read" and watch it read fd #4
>    over and over and over again.
> 
>    If you need any additional info, please let me know.

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