On 22 September 2015 at 11:19, Martin Steigerwald <martin@xxxxxxxxxxxx> wrote:
> with 4.3-rc2 kernel (self-compiled) I get:
>
> merkaba:~> LANG=C chrt -r -p 5 $$
> chrt: failed to set pid 3464's policy: Operation not permitted
>
> called with root rights (either su shell or even a direct tty)
>
> strace reports:
>
> sched_setscheduler(3464, SCHED_RR, { 5 }) = -1 EPERM (Operation not permitted)
>
>
> With 4.1 standard Debian kernel it works.
>
>
> Any idea?
>
> I know I can use setcap to check file capabilities. But I am not sure how to
> see the capabilities of a running process.
>
> Is it /proc/$$/status?
>
> On 4.3-rc2 kernel it tells me:
>
> CapInh: 0000000000000000
> CapPrm: 0000003fffffffff
> CapEff: 0000003fffffffff
> CapBnd: 0000003fffffffff
> CapAmb: 0000000000000000
>
> On 4.1 Debian kernel on a different machine it tells me:
>
> CapInh: 0000000000000000
> CapPrm: 0000003fffffffff
> CapEff: 0000003fffffffff
> CapBnd: 0000003fffffffff
>
> (there is no CapAmb there)
>
> as well, when logged in via SSH, yet chrt -r -p 5 $$ works there as well.
>
> Is there a command displaying available capabilities of a process in clear
> text?
>
>
>
>> xzgrep SCHED config-4.3.0-rc2-tp520.xz
> CONFIG_HAVE_UNSTABLE_SCHED_CLOCK=y
> CONFIG_CGROUP_SCHED=y
> CONFIG_FAIR_GROUP_SCHED=y
> CONFIG_RT_GROUP_SCHED=y
> CONFIG_SCHED_AUTOGROUP=y
> CONFIG_IOSCHED_NOOP=y
> CONFIG_IOSCHED_DEADLINE=y
> CONFIG_IOSCHED_CFQ=y
> CONFIG_CFQ_GROUP_IOSCHED=y
> CONFIG_DEFAULT_IOSCHED="cfq"
> CONFIG_SCHED_OMIT_FRAME_POINTER=y
> CONFIG_SCHED_SMT=y
> CONFIG_SCHED_MC=y
> CONFIG_SCHED_HRTICK=y
> CONFIG_NET_SCHED=y
> CONFIG_USB_EHCI_TT_NEWSCHED=y
> CONFIG_SCHED_DEBUG=y
> CONFIG_SCHED_INFO=y
> CONFIG_SCHEDSTATS=y
> # CONFIG_SCHED_STACK_END_CHECK is not set
> # CONFIG_SCHED_TRACER is not set
>
>
> mango:~# grep SCHED /boot/config-4.1.0-2-amd64
> CONFIG_HAVE_UNSTABLE_SCHED_CLOCK=y
> CONFIG_CGROUP_SCHED=y
> CONFIG_FAIR_GROUP_SCHED=y
> # CONFIG_RT_GROUP_SCHED is not set
> CONFIG_SCHED_AUTOGROUP=y
> CONFIG_IOSCHED_NOOP=y
> CONFIG_IOSCHED_DEADLINE=y
> CONFIG_IOSCHED_CFQ=y
> CONFIG_CFQ_GROUP_IOSCHED=y
> CONFIG_DEFAULT_IOSCHED="cfq"
> CONFIG_SCHED_OMIT_FRAME_POINTER=y
> CONFIG_SCHED_SMT=y
> CONFIG_SCHED_MC=y
> CONFIG_SCHED_HRTICK=y
> CONFIG_NET_SCHED=y
> CONFIG_USB_EHCI_TT_NEWSCHED=y
> CONFIG_SCHED_DEBUG=y
> # CONFIG_SCHEDSTATS is not set
> # CONFIG_SCHED_STACK_END_CHECK is not set
> # CONFIG_SCHED_TRACER is not set
>
>
> Both Debian Sid systems use systemd 226-3.
Hi Martin,
You might be hitting branch CONFIG_RT_GROUP_SCHED enabled.
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/kernel/sched/core.c#n3863
See also.
http://cateee.net/lkddb/web-lkddb/RT_GROUP_SCHED.html
--
Sami Kerola
http://www.iki.fi/kerolasa/
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