Peter Zijlstra a233f1120c sched: Prepare for per-cpu preempt_count ...

When using per-cpu preempt_count variables we need to save/restore the
preempt_count on context switch (into per task storage; for instance
the old thread_info::preempt_count variable) because of
PREEMPT_ACTIVE.

However, this means that on fork() the preempt_count value of the last
context switch gets copied and if we had a PREEMPT_ACTIVE switch right
before cloning a child task the child task will now too have
PREEMPT_ACTIVE set and start its life with an extra PREEMPT_ACTIVE
count.

Therefore we need to make init_task_preempt_count() unconditional;
this resets whatever preempt_count we inherited from our parent
process.

Doing so for !per-cpu implementations is harmless.

For !PREEMPT_COUNT kernels we need to be careful not to start life
with an increased preempt_count.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-4k0b7oy1rcdyzochwiixuwi9@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2013-09-25 14:07:55 +02:00

..

cpu

sched: Add NEED_RESCHED to the preempt_count

2013-09-25 14:07:49 +02:00

debug

kgdb/sysrq: fix inconstistent help message of sysrq key

2013-04-30 17:04:10 -07:00

events

uprobes: Fix utask->depth accounting in handle_trampoline()

2013-09-12 08:00:55 +02:00

gcov

kernel: replace strict_strto*() with kstrto*()

2013-09-12 15:38:03 -07:00

irq

Remove GENERIC_HARDIRQ config option

2013-09-13 15:09:52 +02:00

power

ACPI and power management fixes for 3.12-rc1

2013-09-12 11:22:45 -07:00

printk

TTY/Serial driver patches for 3.12-rc1

2013-09-03 11:38:36 -07:00

sched

sched: Prepare for per-cpu preempt_count

2013-09-25 14:07:55 +02:00

time

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

2013-09-04 09:36:54 -07:00

trace

Not much changes for the 3.12 merge window. The major tracing changes

2013-09-09 14:42:15 -07:00

.gitignore

kernel/hz.bc: ignore.

2013-04-22 07:09:06 -07:00

acct.c

fs: Fix hang with BSD accounting on frozen filesystem

2013-05-04 14:57:58 -04:00

async.c

async: rename and redefine async_func_ptr

2013-03-12 13:59:14 -07:00

audit_tree.c

kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules()

2013-06-12 16:29:46 -07:00

audit_watch.c

audit: catch possible NULL audit buffers

2013-01-11 14:54:55 -08:00

audit.c

audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE

2013-06-12 16:29:45 -07:00

audit.h

audit: fix mq_open and mq_unlink to add the MQ root as a hidden parent audit_names record

2013-07-09 10:33:19 -07:00

auditfilter.c

audit: Fix decimal constant description

2013-07-09 10:33:19 -07:00

auditsc.c

audit: fix mq_open and mq_unlink to add the MQ root as a hidden parent audit_names record

2013-07-09 10:33:19 -07:00

backtracetest.c

…

bounds.c

…

capability.c

xfs: update for v3.12-rc1

2013-09-09 11:19:09 -07:00

cgroup_freezer.c

cgroup: make css_for_each_descendant() and friends include the origin css in the iteration

2013-08-08 20:11:27 -04:00

cgroup.c

Kill indirect include of file.h from eventfd.h, use fdget() in cgroup.c

2013-09-07 19:54:57 -04:00

compat.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

2013-05-01 07:21:43 -07:00

configs.c

proc: Supply PDE attribute setting accessor functions

2013-05-01 17:29:18 -04:00

context_tracking.c

sched: Extract the basic add/sub preempt_count modifiers

2013-09-25 14:07:54 +02:00

cpu_pm.c

kernel/cpu_pm.c: fix various typos

2012-05-31 17:49:27 -07:00

cpu.c

ACPI / processor: Acquire writer lock to update CPU maps

2013-08-13 12:20:16 +02:00

cpuset.c

Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2013-09-03 18:25:03 -07:00

crash_dump.c

…

cred.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2012-12-18 10:55:28 -08:00

delayacct.c

cputime: Use accessors to read task cputime stats

2013-01-27 19:23:31 +01:00

dma.c

Remove all #inclusions of asm/system.h

2012-03-28 18:30:03 +01:00

elfcore.c

…

exec_domain.c

…

exit.c

ptrace: revert "Prepare to fix racy accesses on task breakpoints"

2013-07-09 10:33:26 -07:00

extable.c

extable: skip sorting if the table is empty

2013-09-11 15:58:25 -07:00

fork.c

Merge git://git.kvack.org/~bcrl/aio-next

2013-09-13 10:55:58 -07:00

freezer.c

freezer: set PF_SUSPEND_TASK flag on tasks that call freeze_processes

2013-07-30 14:05:06 +02:00

futex_compat.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

2013-02-23 18:50:11 -08:00

futex.c

futex: Use freezable blocking call

2013-06-25 23:11:19 +02:00

groups.c

userns: Kill nsown_capable it makes the wrong thing easy

2013-08-30 23:44:11 -07:00

hrtimer.c

kernel: delete __cpuinit usage from all core kernel files

2013-07-14 19:36:59 -04:00

hung_task.c

hung_task debugging: Print more info when reporting the problem

2013-08-02 11:02:42 +02:00

irq_work.c

Merge branch 'nohz/printk-v8' into irq/core

2013-02-05 00:48:46 +01:00

itimer.c

itimer: Use printk_once instead of WARN_ONCE

2012-04-10 11:00:30 +02:00

jump_label.c

jump_label: Split jumplabel ratelimit

2013-08-09 07:53:54 -07:00

kallsyms.c

kernel: kallsyms: memory override issue, need check destination buffer length

2013-04-15 15:17:26 +09:30

kcmp.c

kcmp: include linux/ptrace.h

2012-12-20 17:40:19 -08:00

Kconfig.freezer

…

Kconfig.hz

…

Kconfig.locks

locking: Fix copy/paste errors of "ARCH_INLINE_*_UNLOCK_BH"

2013-05-28 08:50:00 +02:00

Kconfig.preempt

locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage

2012-03-23 13:18:57 +01:00

kexec.c

kexec: remove unnecessary return

2013-09-11 15:59:10 -07:00

kmod.c

usermodehelper: kill the sub_info->path[0] check

2013-07-03 16:08:02 -07:00

kprobes.c

kprobes: allow to specify custom allocator for insn caches

2013-09-11 15:58:52 -07:00

ksysfs.c

kernel: replace strict_strto*() with kstrto*()

2013-09-12 15:38:03 -07:00

kthread.c

kthread: implement probe_kthread_data()

2013-04-30 17:04:02 -07:00

latencytop.c

…

lglock.c

lglock: Update lockdep annotations to report recursive local locks

2013-07-12 13:51:19 +02:00

lockdep_internals.h

…

lockdep_proc.c

lockdep: Use KSYM_NAME_LEN'ed buffer for __get_key_name()

2012-10-24 12:39:09 +02:00

lockdep_states.h

…

lockdep.c

lockdep: remove task argument from debug_check_no_locks_held

2013-05-12 14:16:21 +02:00

Makefile

Remove GENERIC_HARDIRQ config option

2013-09-13 15:09:52 +02:00

modsign_certificate.S

CONFIG_SYMBOL_PREFIX: cleanup.

2013-03-15 15:09:43 +10:30

modsign_pubkey.c

kernel/modsign_pubkey.c: fix init const for module signing code

2013-09-11 15:58:21 -07:00

module_signing.c

MODSIGN: Don't use enum-type bitfields in module signature info block

2012-12-05 11:27:24 +10:30

module-internal.h

MODSIGN: Move the magic string to the end of a module and eliminate the search

2012-10-19 17:30:40 -07:00

module.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-09-05 08:50:26 -07:00

mutex-debug.c

…

mutex-debug.h

…

mutex.c

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

2013-09-04 08:18:19 -07:00

mutex.h

…

notifier.c

…

nsproxy.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2013-09-07 14:35:32 -07:00

padata.c

padata - Register hotcpu notifier after initialization

2013-08-29 14:37:59 +10:00

panic.c

panic: call panic handlers before kmsg_dump

2013-09-11 15:59:30 -07:00

params.c

kernel: replace strict_strto*() with kstrto*()

2013-09-12 15:38:03 -07:00

pid_namespace.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2013-09-07 14:35:32 -07:00

pid.c

pidns: Fix hang in zap_pid_ns_processes by sending a potentially extra wakeup

2013-08-30 17:30:37 -07:00

posix-cpu-timers.c

posix_timers: fix racy timer delta caching on task exit

2013-07-03 16:54:42 +02:00

posix-timers.c

posix-timers: Remove unused variable

2013-04-18 12:51:19 +02:00

profile.c

kernel: delete __cpuinit usage from all core kernel files

2013-07-14 19:36:59 -04:00

ptrace.c

__ptrace_may_access() should not deny sub-threads

2013-09-11 15:59:01 -07:00

range.c

range: Do not add new blank slot with add_range_with_merge

2013-06-18 11:32:10 -05:00

rcu.h

rcu: Make call_rcu() leak callbacks for debug-object errors

2013-08-18 17:40:03 -07:00

rcupdate.c

Not much changes for the 3.12 merge window. The major tracing changes

2013-09-09 14:42:15 -07:00

rcutiny_plugin.h

rcu: Add const annotation to char * for RCU tracepoints and functions

2013-07-29 17:07:49 -04:00

rcutiny.c

rcu: Add const annotation to char * for RCU tracepoints and functions

2013-07-29 17:07:49 -04:00

rcutorture.c

rcu: Make rcutorture emit online failures if verbose

2013-08-20 11:38:45 -07:00

rcutree_plugin.h

nohz_full: Force RCU's grace-period kthreads onto timekeeping CPU

2013-08-31 14:44:02 -07:00

rcutree_trace.c

rcutrace: single_open() leaks

2013-05-05 00:16:35 -04:00

rcutree.c

sched, rcu: Make RCU use resched_cpu()

2013-09-25 13:53:08 +02:00

rcutree.h

nohz_full: Force RCU's grace-period kthreads onto timekeeping CPU

2013-08-31 14:44:02 -07:00

reboot.c

reboot: move arch/x86 reboot= handling to generic kernel

2013-07-09 10:33:29 -07:00

relay.c

kernel: delete __cpuinit usage from all core kernel files

2013-07-14 19:36:59 -04:00

res_counter.c

memcg: reduce function dereference

2013-09-12 15:38:02 -07:00

resource.c

kernel/resource.c: remove the unneeded assignment in function __find_resource

2013-07-03 16:08:06 -07:00

rtmutex_common.h

…

rtmutex-debug.c

sched/rt: Move rt specific bits into new header file

2013-02-07 20:51:08 +01:00

rtmutex-debug.h

…

rtmutex-tester.c

locking/rtmutex/tester: Set correct permissions on sysfs files

2013-04-10 14:48:37 +02:00

rtmutex.c

rtmutex: Document rt_mutex_adjust_prio_chain()

2013-05-28 09:23:52 +02:00

rtmutex.h

…

rwsem.c

Revert "rw_semaphore: remove up/down_read_non_owner"

2013-03-23 15:53:52 -07:00

seccomp.c

seccomp: allow BPF_XOR based ALU instructions.

2013-03-26 11:07:19 +11:00

semaphore.c

semaphore: use `bool' type for semaphore_waiter's up

2013-04-30 17:04:08 -07:00

signal.c

kernel-wide: fix missing validations on __get/__put/__copy_to/__copy_from_user()

2013-09-11 15:58:18 -07:00

smp.c

kernel/smp.c: quit unconditionally enabling irqs in on_each_cpu_mask().

2013-09-11 15:58:25 -07:00

smpboot.c

kernel: delete __cpuinit usage from all core kernel files

2013-07-14 19:36:59 -04:00

smpboot.h

smpboot: Provide infrastructure for percpu hotplug threads

2012-08-13 17:01:07 +02:00

softirq.c

sched: Extract the basic add/sub preempt_count modifiers

2013-09-25 14:07:54 +02:00

spinlock.c

kernel/spinlock.c: add default arch_*_relax definitions for GENERIC_LOCKBREAK

2013-09-11 15:58:21 -07:00

srcu.c

srcu: use ACCESS_ONCE() to access sp->completed in srcu_read_lock()

2013-02-07 15:19:36 -08:00

stacktrace.c

…

stop_machine.c

stop_machine: Mark per cpu stopper enabled early

2013-02-26 22:25:17 +01:00

sys_ni.c

unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE

2013-05-09 13:46:38 -04:00

sys.c

userns: Kill nsown_capable it makes the wrong thing easy

2013-08-30 23:44:11 -07:00

sysctl_binary.c

kernel: remove unnecessary head file

2013-06-26 18:01:46 +09:00

sysctl.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-09-12 15:01:38 -07:00

task_work.c

task_work: documentation

2013-09-11 15:58:27 -07:00

taskstats.c

taskstats: cgroupstats_user_cmd() may leak on error

2012-10-06 03:05:31 +09:00

test_kprobes.c

kernel/: rename random32() to prandom_u32()

2013-04-29 18:28:42 -07:00

time.c

sched: Rename sched.c as sched/core.c in comments and Documentation

2013-06-19 12:58:42 +02:00

timeconst.bc

kernel: Replace timeconst.pl with a bc script

2013-02-16 23:17:25 +01:00

timer.c

sched: Introduce preempt_count accessor functions

2013-09-25 14:07:32 +02:00

tracepoint.c

Tracing updates for Linux 3.10

2013-04-29 13:55:38 -07:00

tsacct.c

cputime: Use accessors to read task cputime stats

2013-01-27 19:23:31 +01:00

uid16.c

userns: Kill nsown_capable it makes the wrong thing easy

2013-08-30 23:44:11 -07:00

up.c

smp.h: move !SMP version of on_each_cpu() out-of-line

2013-09-11 15:58:25 -07:00

user_namespace.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2013-09-07 14:35:32 -07:00

user-return-notifier.c

hlist: drop the node parameter from iterators

2013-02-27 19:10:24 -08:00

user.c

userns: Better restrictions on when proc and sysfs can be mounted

2013-08-26 19:17:03 -07:00

utsname_sysctl.c

kernel/utsname_sysctl.c: put get/get_uts() into CONFIG_PROC_SYSCTL code block

2013-02-27 19:10:22 -08:00

utsname.c

userns: Kill nsown_capable it makes the wrong thing easy

2013-08-30 23:44:11 -07:00

wait.c

kernel: fix new kernel-doc warning in wait.c

2013-08-19 09:08:54 -07:00

watchdog.c

watchdog: Make it work under full dynticks

2013-07-30 22:29:15 +02:00

workqueue_internal.h

sched: Rename sched.c as sched/core.c in comments and Documentation

2013-06-19 12:58:42 +02:00

workqueue.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2013-09-06 09:36:28 -07:00