linux.git/kernel, branch v3.19-rc4

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

2015-01-11T19:51:49+00:00

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes: group scheduling corner case fix, two deadline scheduler
  fixes, effective_load() overflow fix, nested sleep fix, 6144 CPUs
  system fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix RCU stall upon -ENOMEM in sched_create_group()
  sched/deadline: Avoid double-accounting in case of missed deadlines
  sched/deadline: Fix migration of SCHED_DEADLINE tasks
  sched: Fix odd values in effective_load() calculations
  sched, fanotify: Deal with nested sleeps
  sched: Fix KMALLOC_MAX_SIZE overflow during cpumask allocation

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

2015-01-11T19:47:45+00:00

Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, but also some kernel side fixes: uncore PMU
  driver fix, user regs sampling fix and an instruction decoder fix that
  unbreaks PEBS precise sampling"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/uncore/hsw-ep: Handle systems with only two SBOXes
  perf/x86_64: Improve user regs sampling
  perf: Move task_pt_regs sampling into arch code
  x86: Fix off-by-one in instruction decoder
  perf hists browser: Fix segfault when showing callchain
  perf callchain: Free callchains when hist entries are deleted
  perf hists: Fix children sort key behavior
  perf diff: Fix to sort by baseline field by default
  perf list: Fix --raw-dump option
  perf probe: Fix crash in dwarf_getcfi_elf
  perf probe: Fix to fall back to find probe point in symbols
  perf callchain: Append callchains only when requested
  perf ui/tui: Print backtrace symbols when segfault occurs
  perf report: Show progress bar for output resorting

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

2015-01-11T19:46:31+00:00

Pull locking fixes from Ingo Molnar:
 "A liblockdep fix and a mutex_unlock() mutex-debugging fix"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  mutex: Always clear owner field upon mutex_unlock()
  tools/liblockdep: Fix debug_check thinko in mutex destroy

Merge tag 'for_linus-3.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

2015-01-10T04:51:10+00:00

Pull kgdb/kdb fixes from Jason Wessel:
 "These have been around since 3.17 and in kgdb-next for the last 9
  weeks and some will go back to -stable.

  Summary of changes:

  Cleanups
   - kdb: Remove unused command flags, repeat flags and KDB_REPEAT_NONE

  Fixes
   - kgdb/kdb: Allow access on a single core, if a CPU round up is
     deemed impossible, which will allow inspection of the now "trashed"
     kernel
   - kdb: Add enable mask for the command groups
   - kdb: access controls to restrict sensitive commands"

* tag 'for_linus-3.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  kernel/debug/debug_core.c: Logging clean-up
  kgdb: timeout if secondary CPUs ignore the roundup
  kdb: Allow access to sensitive commands to be restricted by default
  kdb: Add enable mask for groups of commands
  kdb: Categorize kdb commands (similar to SysRq categorization)
  kdb: Remove KDB_REPEAT_NONE flag
  kdb: Use KDB_REPEAT_* values as flags
  kdb: Rename kdb_register_repeat() to kdb_register_flags()
  kdb: Rename kdb_repeat_t to kdb_cmdflags_t, cmd_repeat to cmd_flags
  kdb: Remove currently unused kdbtab_t->cmd_flags

mutex: Always clear owner field upon mutex_unlock()

2015-01-09T10:20:39+00:00

Currently if DEBUG_MUTEXES is enabled, the mutex->owner field is only
cleared iff debug_locks is active. This exposes a race to other users of
the field where the mutex->owner may be still set to a stale value,
potentially upsetting mutex_spin_on_owner() among others.

References: https://bugs.freedesktop.org/show_bug.cgi?id=87955
Signed-off-by: Chris Wilson 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Davidlohr Bueso 
Cc: Daniel Vetter 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/1420540175-30204-1-git-send-email-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar

sched/fair: Fix RCU stall upon -ENOMEM in sched_create_group()

2015-01-09T10:19:00+00:00

When alloc_fair_sched_group() in sched_create_group() fails,
free_sched_group() is called, and free_fair_sched_group() is called by
free_sched_group(). Since destroy_cfs_bandwidth() is called by
free_fair_sched_group() without calling init_cfs_bandwidth(),
RCU stall occurs at hrtimer_cancel():

  INFO: rcu_sched self-detected stall on CPU { 1}  (t=60000 jiffies g=13074 c=13073 q=0)
  Task dump for CPU 1:
  (fprintd)       R  running task        0  6249      1 0x00000088
  ...
  Call Trace:
     [] sched_show_task+0xa8/0x110
   [] dump_cpu_task+0x3d/0x50
   [] rcu_dump_cpu_stacks+0x90/0xd0
   [] rcu_check_callbacks+0x491/0x700
   [] update_process_times+0x4b/0x80
   [] tick_sched_handle.isra.20+0x36/0x50
   [] tick_sched_timer+0x42/0x70
   [] __run_hrtimer+0x69/0x1a0
   [] ? tick_sched_handle.isra.20+0x50/0x50
   [] hrtimer_interrupt+0xef/0x230
   [] local_apic_timer_interrupt+0x3b/0x70
   [] smp_apic_timer_interrupt+0x45/0x60
   [] apic_timer_interrupt+0x6d/0x80
     [] ? lock_hrtimer_base.isra.23+0x18/0x50
   [] ? __kmalloc+0x211/0x230
   [] hrtimer_try_to_cancel+0x22/0xd0
   [] ? __kmalloc+0x211/0x230
   [] hrtimer_cancel+0x22/0x30
   [] free_fair_sched_group+0x25/0xd0
   [] free_sched_group+0x16/0x40
   [] sched_create_group+0x4b/0x80
   [] sched_autogroup_create_attach+0x43/0x1c0
   [] sys_setsid+0x7c/0x110
   [] system_call_fastpath+0x12/0x17

Check whether init_cfs_bandwidth() was called before calling
destroy_cfs_bandwidth().

Signed-off-by: Tetsuo Handa 
[ Move the check into destroy_cfs_bandwidth() to aid compilability. ]
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Paul Turner 
Cc: Ben Segall 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/201412252210.GCC30204.SOMVFFOtQJFLOH@I-love.SAKURA.ne.jp
Signed-off-by: Ingo Molnar

sched/deadline: Avoid double-accounting in case of missed deadlines

2015-01-09T10:18:57+00:00

The dl_runtime_exceeded() function is supposed to ckeck if
a SCHED_DEADLINE task must be throttled, by checking if its
current runtime is <= 0. However, it also checks if the
scheduling deadline has been missed (the current time is
larger than the current scheduling deadline), further
decreasing the runtime if this happens.
This "double accounting" is wrong:

- In case of partitioned scheduling (or single CPU), this
  happens if task_tick_dl() has been called later than expected
  (due to small HZ values). In this case, the current runtime is
  also negative, and replenish_dl_entity() can take care of the
  deadline miss by recharging the current runtime to a value smaller
  than dl_runtime

- In case of global scheduling on multiple CPUs, scheduling
  deadlines can be missed even if the task did not consume more
  runtime than expected, hence penalizing the task is wrong

This patch fix this problem by throttling a SCHED_DEADLINE task
only when its runtime becomes negative, and not modifying the runtime

Signed-off-by: Luca Abeni 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Juri Lelli 
Cc: 
Cc: Dario Faggioli 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/1418813432-20797-3-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar

sched/deadline: Fix migration of SCHED_DEADLINE tasks

2015-01-09T10:18:56+00:00

According to global EDF, tasks should be migrated between runqueues
without checking if their scheduling deadlines and runtimes are valid.
However, SCHED_DEADLINE currently performs such a check:
a migration happens doing:

	deactivate_task(rq, next_task, 0);
	set_task_cpu(next_task, later_rq->cpu);
	activate_task(later_rq, next_task, 0);

which ends up calling dequeue_task_dl(), setting the new CPU, and then
calling enqueue_task_dl().

enqueue_task_dl() then calls enqueue_dl_entity(), which calls
update_dl_entity(), which can modify scheduling deadline and runtime,
breaking global EDF scheduling.

As a result, some of the properties of global EDF are not respected:
for example, a taskset {(30, 80), (40, 80), (120, 170)} scheduled on
two cores can have unbounded response times for the third task even
if 30/80+40/80+120/170 = 1.5809 < 2

This can be fixed by invoking update_dl_entity() only in case of
wakeup, or if this is a new SCHED_DEADLINE task.

Signed-off-by: Luca Abeni 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Juri Lelli 
Cc: 
Cc: Dario Faggioli 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/1418813432-20797-2-git-send-email-luca.abeni@unitn.it
Signed-off-by: Ingo Molnar

sched: Fix odd values in effective_load() calculations

2015-01-09T10:18:54+00:00

In effective_load, we have (long w * unsigned long tg->shares) / long W,
when w is negative, it is cast to unsigned long and hence the product is
insanely large. Fix this by casting tg->shares to long.

Reported-by: Sasha Levin 
Signed-off-by: Yuyang Du 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Dave Jones 
Cc: Andrey Ryabinin 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/20141219002956.GA25405@intel.com
Signed-off-by: Ingo Molnar

perf: Move task_pt_regs sampling into arch code

2015-01-09T10:12:28+00:00

On x86_64, at least, task_pt_regs may be only partially initialized
in many contexts, so x86_64 should not use it without extra care
from interrupt context, let alone NMI context.

This will allow x86_64 to override the logic and will supply some
scratch space to use to make a cleaner copy of user regs.

Tested-by: Jiri Olsa 
Signed-off-by: Andy Lutomirski 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Stephane Eranian 
Cc: chenggang.qcg@taobao.com
Cc: Wu Fengguang 
Cc: Namhyung Kim 
Cc: Mike Galbraith 
Cc: Arjan van de Ven 
Cc: David Ahern 
Cc: Arnaldo Carvalho de Melo 
Cc: Catalin Marinas 
Cc: Jean Pihet 
Cc: Linus Torvalds 
Cc: Mark Salter 
Cc: Russell King 
Cc: Will Deacon 
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/e431cd4c18c2e1c44c774f10758527fb2d1025c4.1420396372.git.luto@amacapital.net
Signed-off-by: Ingo Molnar