linux-toradex.git/kernel/sched/core.c, branch v3.14.3

sched/deadline: Deny unprivileged users to set/change SCHED_DEADLINE policy

2014-03-11T10:33:46+00:00

Deny the use of SCHED_DEADLINE policy to unprivileged users.
Even if root users can set the policy for normal users, we
don't want the latter to be able to change their parameters
(safest behavior).

Signed-off-by: Juri Lelli 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1393844961-18097-1-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar

sched: Add 'flags' argument to sched_{set,get}attr() syscalls

2014-02-21T20:27:10+00:00

Because of a recent syscall design debate; its deemed appropriate for
each syscall to have a flags argument for future extension; without
immediately requiring new syscalls.

Cc: juri.lelli@gmail.com
Cc: Ingo Molnar 
Suggested-by: Michael Kerrisk 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20140214161929.GL27965@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner

sched: Fix information leak in sys_sched_getattr()

2014-02-21T20:27:10+00:00

We're copying the on-stack structure to userspace, but forgot to give
the right number of bytes to copy. This allows the calling process to
obtain up to PAGE_SIZE bytes from the stack (and possibly adjacent
kernel memory).

This fix copies only as much as we actually have on the stack
(attr->size defaults to the size of the struct) and leaves the rest of
the userspace-provided buffer untouched.

Found using kmemcheck + trinity.

Fixes: d50dde5a10f30 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Cc: Dario Faggioli 
Cc: Juri Lelli 
Cc: Ingo Molnar 
Signed-off-by: Vegard Nossum 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1392585857-10725-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Thomas Gleixner

sched/core: Make dl_b->lock IRQ safe

2014-02-21T20:27:10+00:00

Fix this lockdep warning:

[   44.804600] =========================================================
[   44.805746] [ INFO: possible irq lock inversion dependency detected ]
[   44.805746] 3.14.0-rc2-test+ #14 Not tainted
[   44.805746] ---------------------------------------------------------
[   44.805746] bash/3674 just changed the state of lock:
[   44.805746]  (&dl_b->lock){+.....}, at: [] sched_rt_handler+0x132/0x248
[   44.805746] but this lock was taken by another, HARDIRQ-safe lock in the past:
[   44.805746]  (&rq->lock){-.-.-.}

and interrupts could create inverse lock ordering between them.

[   44.805746]
[   44.805746] other info that might help us debug this:
[   44.805746]  Possible interrupt unsafe locking scenario:
[   44.805746]
[   44.805746]        CPU0                    CPU1
[   44.805746]        ----                    ----
[   44.805746]   lock(&dl_b->lock);
[   44.805746]                                local_irq_disable();
[   44.805746]                                lock(&rq->lock);
[   44.805746]                                lock(&dl_b->lock);
[   44.805746]   
[   44.805746]     lock(&rq->lock);

by making dl_b->lock acquiring always IRQ safe.

Cc: Ingo Molnar 
Signed-off-by: Juri Lelli 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1392107067-19907-3-git-send-email-juri.lelli@gmail.com
Signed-off-by: Thomas Gleixner

sched/core: Fix sched_rt_global_validate

2014-02-21T20:27:10+00:00

Don't compare sysctl_sched_rt_runtime against sysctl_sched_rt_period if
the former is equal to RUNTIME_INF, otherwise disabling -rt bandwidth
management (with CONFIG_RT_GROUP_SCHED=n) fails.

Cc: Ingo Molnar 
Signed-off-by: Juri Lelli 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1392107067-19907-2-git-send-email-juri.lelli@gmail.com
Signed-off-by: Thomas Gleixner

sched/deadline: Fix overflow to handle period==0 and deadline!=0

2014-02-21T20:27:09+00:00

While debugging the crash with the bad nr_running accounting, I hit
another bug where, after running my sched deadline test, I was getting
failures to take a CPU offline. It was giving me a -EBUSY error.

Adding a bunch of trace_printk()s around, I found that the cpu
notifier that called sched_cpu_inactive() was returning a failure. The
overflow value was coming up negative?

Talking this over with Juri, the problem is that the total_bw update was
suppose to be made by dl_overflow() which, during my tests, seemed to
not be called. Adding more trace_printk()s, it wasn't that it wasn't
called, but it exited out right away with the check of new_bw being
equal to p->dl.dl_bw. The new_bw calculates the ratio between period and
runtime. The bug is that if you set a deadline, you do not need to set
a period if you plan on the period being equal to the deadline. That
is, if period is zero and deadline is not, then the system call should
set the period to be equal to the deadline. This is done elsewhere in
the code.

The fix is easy, check if period is set, and if it is not, then use the
deadline.

Cc: Juri Lelli 
Cc: Ingo Molnar 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Signed-off-by: Steven Rostedt 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20140219135335.7e74abd4@gandalf.local.home
Signed-off-by: Thomas Gleixner

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-01-31T17:02:51+00:00

Pull timer/dynticks updates from Ingo Molnar:
 "This tree contains misc dynticks updates: a fix and three cleanups"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/nohz: Fix overflow error in scheduler_tick_max_deferment()
  nohz_full: fix code style issue of tick_nohz_full_stop_tick
  nohz: Get timekeeping max deferment outside jiffies_lock
  tick: Rename tick_check_idle() to tick_irq_enter()

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-01-31T17:00:44+00:00

Pull scheduler fixes from Ingo Molnar:
 "A crash fix and documentation updates"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Make sched_class::get_rr_interval() optional
  sched/deadline: Add sched_dl documentation
  sched: Fix docbook parameter annotation error in wait.h

sched: Make sched_class::get_rr_interval() optional

2014-01-28T12:08:41+00:00

Not all classes implement (or can implement) a useful get_rr_interval()
function, default to a 0 time-slice for them.

This fixes a crash reported by Tommi Rantala.

Reported-by: Tommi Rantala 
Cc: Dave Jones 
Cc: Tommi Rantala 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20140127105413.GC11314@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar

Merge branch 'timers/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/urgent

2014-01-25T07:27:26+00:00

Pull dynticks cleanups from Frederic Weisbecker.

Signed-off-by: Ingo Molnar