Ingo Molnar af6d596fd6 sched: prevent divide by zero error in cpu_avg_load_per_task, update ...

Regarding the bug addressed in:

  4cd4262: sched: prevent divide by zero error in cpu_avg_load_per_task

Linus points out that the fix is not complete:

> There's nothing that keeps gcc from deciding not to reload
> rq->nr_running.
>
> Of course, in _practice_, I don't think gcc ever will (if it decides
> that it will spill, gcc is likely going to decide that it will
> literally spill the local variable to the stack rather than decide to
> reload off the pointer), but it's a valid compiler optimization, and
> it even has a name (rematerialization).
>
> So I suspect that your patch does fix the bug, but it still leaves the
> fairly unlikely _potential_ for it to re-appear at some point.
>
> We have ACCESS_ONCE() as a macro to guarantee that the compiler
> doesn't rematerialize a pointer access. That also would clarify
> the fact that we access something unsafe outside a lock.

So make sure our nr_running value is immutable and cannot change
after we check it for nonzero.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

2008-11-29 20:45:15 +01:00

..

irq

irq: make variable static

2008-10-22 07:37:17 +02:00

power

suspend: use WARN not WARN_ON to print the message

2008-11-18 08:07:36 -08:00

time

nohz: disable tick_nohz_kick_tick() for now

2008-11-10 22:39:27 +01:00

trace

function tracing: fix wrong pos computing when read buffer has been fulfilled

2008-11-16 08:32:05 +01:00

.gitignore

Update kernel/.gitignore with new auto-generated files

2008-02-09 23:27:01 -08:00

acct.c

tty: Fix abusers of current->sighand->tty

2008-10-13 09:51:42 -07:00

audit_tree.c

Fix inotify watch removal/umount races

2008-11-15 12:26:44 -08:00

audit.c

[PATCH] Fix the bug of using AUDIT_STATUS_RATE_LIMIT when set fail, no error output.

2008-08-01 12:15:16 -04:00

audit.h

[PATCH 1/2] audit: move extern declarations to audit.h

2008-04-28 06:28:04 -04:00

auditfilter.c

Fix inotify watch removal/umount races

2008-11-15 12:26:44 -08:00

auditsc.c

tty: Fix abusers of current->sighand->tty

2008-10-13 09:51:42 -07:00

backtracetest.c

backtrace: replace timer with tasklet + completions

2008-06-27 18:09:16 +02:00

bounds.c

Add kbuild.h that contains common definitions for kbuild users

2008-04-29 08:06:29 -07:00

capability.c

security: Fix setting of PF_SUPERPRIV by __capable()

2008-08-14 22:59:43 +10:00

cgroup_debug.c

cgroups: fix probable race with put_css_set[_taskexit] and find_css_set

2008-10-20 08:52:38 -07:00

cgroup_freezer.c

freezer_cg: disable writing freezer.state of root cgroup

2008-11-12 17:17:16 -08:00

cgroup.c

cgroups: fix a serious bug in cgroupstats

2008-11-19 18:50:00 -08:00

compat.c

Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus

2008-10-20 13:14:06 +02:00

configs.c

kernel/configs.c: remove useless comments

2008-10-20 08:52:34 -07:00

cpu.c

cpumask: introduce new API, without changing anything

2008-11-06 09:05:33 +01:00

cpuset.c

sched, cpusets: fix warning in kernel/cpuset.c

2008-11-29 20:39:29 +01:00

delayacct.c

per-task-delay-accounting: update taskstats for memory reclaim delay

2008-07-25 10:53:47 -07:00

dma-coherent.c

dma-coherent: export dma_[alloc|release]_from_coherent methods

2008-08-22 08:34:53 +02:00

dma.c

kernel/dma.c: remove a CVS keyword

2008-10-16 11:21:30 -07:00

exec_domain.c

proc: move /proc/execdomains to kernel/exec_domain.c

2008-10-23 14:30:41 +04:00

exit.c

Move "exit_robust_list" into mm_release()

2008-11-15 10:20:36 -08:00

extable.c

module: Don't report discarded init pages as kernel text.

2008-01-29 17:13:18 +11:00

fork.c

Move "exit_robust_list" into mm_release()

2008-11-15 10:20:36 -08:00

freezer.c

freezer_cg: use thaw_process() in unfreeze_cgroup()

2008-10-30 11:38:45 -07:00

futex_compat.c

futex_compat __user annotation

2008-03-30 14:18:41 -07:00

futex.c

hrtimer: make the futex() system call use the per process slack value

2008-09-11 07:17:00 -07:00

hrtimer.c

hrtimer: clean up unused callback modes

2008-11-12 09:54:40 +01:00

itimer.c

timers: fix itimer/many thread hang

2008-09-14 16:25:35 +02:00

kallsyms.c

sprint_symbol(): use less stack

2008-11-19 18:49:58 -08:00

Kconfig.freezer

container freezer: implement freezer cgroup subsystem

2008-10-20 08:52:34 -07:00

Kconfig.hz

sched: fix SCHED_HRTICK dependency

2008-07-28 14:37:38 +02:00

Kconfig.preempt

rcu: move PREEMPT_RCU config option back under PREEMPT

2008-03-10 18:01:20 -07:00

kexec.c

kexec: fix crash_save_vmcoreinfo_init build problem

2008-10-20 15:28:50 -07:00

kfifo.c

is_power_of_2: kernel/kfifo.c

2007-07-16 09:05:50 -07:00

kgdb.c

kgdb: call touch_softlockup_watchdog on resume

2008-10-06 13:50:59 -05:00

kmod.c

Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

2008-10-16 12:38:34 -07:00

kprobes.c

kernel/kprobes.c: don't pad kretprobe_table_locks[] on uniprocessor builds

2008-11-12 17:17:17 -08:00

ksysfs.c

profiling: dynamically enable readprofile at runtime

2008-10-16 11:21:31 -07:00

kthread.c

Merge branch 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2008-10-20 13:35:07 -07:00

latencytop.c

kernel: use non-racy method for proc entries creation

2008-04-29 08:06:22 -07:00

lockdep_internals.h

lockdep: build fix

2008-08-13 12:55:10 +02:00

lockdep_proc.c

lockstat: fix numerical output rounding error

2008-08-26 10:37:46 +02:00

lockdep.c

lockdep: fix irqs on/off ip tracing

2008-10-28 11:19:07 +01:00

Makefile

Remove -mno-spe flags as they dont belong

2008-11-17 13:24:35 -08:00

marker.c

markers: bit-field is not thread-safe nor smp-safe

2008-10-14 10:38:45 +02:00

module.c

Merge branch 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc

2008-10-23 12:04:37 -07:00

mutex-debug.c

mutex-debug: check mutex magic before owner

2008-05-16 16:53:35 +02:00

mutex-debug.h

[PATCH] lockdep: better lock debugging

2006-07-03 15:27:01 -07:00

mutex.c

locking: fix mutex @key parameter kernel-doc notation

2008-07-28 18:12:36 +02:00

mutex.h

[PATCH] lockdep: prove mutex locking correctness

2006-07-03 15:27:04 -07:00

notifier.c

ftrace: ignore functions that cannot be kprobe-ed

2008-10-14 10:34:22 +02:00

ns_cgroup.c

cgroup_clone: use pid of newly created task for new cgroup

2008-07-25 10:53:37 -07:00

nsproxy.c

removed unused #include <linux/version.h>'s

2008-08-23 12:14:12 -07:00

panic.c

Make panic= and panic_on_oops into core_params

2008-10-22 10:00:25 +11:00

params.c

Fix compile warning in kernel/params.c

2008-10-23 12:09:00 -07:00

pid_namespace.c

pid_ns: (BUG 11391) change ->child_reaper when init->group_leader exits

2008-09-02 19:21:38 -07:00

pid.c

pidns: remove now unused find_pid function.

2008-07-25 10:53:45 -07:00

pm_qos_params.c

pm_qos_requirement might sleep

2008-09-02 19:21:40 -07:00

posix-cpu-timers.c

sched, signals: fix the racy usage of ->signal in account_group_xxx/run_posix_cpu_timers

2008-11-17 16:49:35 +01:00

posix-timers.c

Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2

2008-10-22 09:48:06 +02:00

printk.c

printk: remove unused code from kernel/printk.c

2008-10-23 21:54:29 +02:00

profile.c

kernel/profile.c: fix section mismatch warning

2008-11-18 08:49:24 +01:00

ptrace.c

make ptrace_untrace() static

2008-10-20 08:52:39 -07:00

rcuclassic.c

rcu: RCU-based detection of stalled CPUs for Classic RCU, fix

2008-10-03 10:41:00 +02:00

rcupdate.c

rcupdate: fix bug of rcu_barrier*()

2008-10-21 15:59:53 +02:00

rcupreempt_trace.c

rcu: trace fix possible mem-leak

2008-08-15 17:54:40 +02:00

rcupreempt.c

byteorder: remove direct includes of linux/byteorder/swab[b].h

2008-10-20 08:52:40 -07:00

rcutorture.c

byteorder: remove direct includes of linux/byteorder/swab[b].h

2008-10-20 12:51:53 -07:00

relay.c

relay: fix cpu offline problem

2008-11-18 15:08:56 +01:00

res_counter.c

cgroup files: convert res_counter_write() to be a cgroups write_string() handler

2008-07-25 10:53:36 -07:00

resource.c

reserve_region_with_split: Fix GFP_KERNEL usage under spinlock

2008-11-01 09:53:58 -07:00

rtmutex_common.h

Don't operate with pid_t in rtmutex tester

2008-02-08 09:22:41 -08:00

rtmutex-debug.c

Don't operate with pid_t in rtmutex tester

2008-02-08 09:22:41 -08:00

rtmutex-debug.h

[PATCH] lockdep: better lock debugging

2006-07-03 15:27:01 -07:00

rtmutex-tester.c

sysdev: Pass the attribute to the low level sysdev show/store function

2008-07-21 21:55:02 -07:00

rtmutex.c

hrtimer: convert kernel/* to the new hrtimer apis

2008-09-05 21:35:13 -07:00

rtmutex.h

[PATCH] lockdep: better lock debugging

2006-07-03 15:27:01 -07:00

rwsem.c

sched: mark rwsem functions as __sched for wchan/profiling

2007-12-18 15:21:13 +01:00

sched_clock.c

sched_clock: prevent scd->clock from moving backwards

2008-10-10 11:17:04 +02:00

sched_cpupri.c

sched: use a 2-d bitmap for searching lowest-pri CPU

2008-06-06 15:19:28 +02:00

sched_cpupri.h

sched: fix the cpuprio count really

2008-06-06 15:19:44 +02:00

sched_debug.c

sched: fix kernel warning on /proc/sched_debug access

2008-11-16 08:07:15 +01:00

sched_fair.c

sched: release buddies on yield

2008-11-11 11:57:22 +01:00

sched_features.h

sched: backward looking buddy

2008-11-05 10:30:14 +01:00

sched_idletask.c

sched: add CONFIG_SMP consistency

2008-10-22 10:01:52 +02:00

sched_rt.c

Merge commit 'v2.6.28-rc1' into sched/urgent

2008-10-24 12:48:46 +02:00

sched_stats.h

sched, signals: fix the racy usage of ->signal in account_group_xxx/run_posix_cpu_timers

2008-11-17 16:49:35 +01:00

sched.c

sched: prevent divide by zero error in cpu_avg_load_per_task, update

2008-11-29 20:45:15 +01:00

seccomp.c

make seccomp zerocost in schedule

2007-07-16 09:05:50 -07:00

semaphore.c

semaphore: __down_common: use signal_pending_state()

2008-08-05 14:33:47 -07:00

signal.c

'kill sig -1' must only apply to caller's namespace

2008-10-30 11:38:46 -07:00

smp.c

generic-ipi: fix the smp_mb() placement

2008-11-06 08:41:56 +01:00

softirq.c

irq: call __irq_enter() before calling the tick_idle_check

2008-11-10 22:36:39 +01:00

softlockup.c

Make the taint flags reliable

2008-10-16 11:21:31 -07:00

spinlock.c

lockdep: spin_lock_nest_lock(), checkpatch fixes

2008-08-13 13:56:51 +02:00

srcu.c

make srcu_readers_active() static

2008-02-06 10:41:02 -08:00

stacktrace.c

stacktrace: fix modular build, export print_stack_trace and save_stack_trace

2008-06-30 09:20:55 +02:00

stop_machine.c

stop_machine: fix race with return value (fixes Bug #11989)

2008-11-16 15:09:52 -08:00

sys_ni.c

reintroduce accept4

2008-11-19 18:49:57 -08:00

sys.c

Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2

2008-10-22 09:48:06 +02:00

sysctl_check.c

sysctl: check for bogus modes

2008-07-25 10:53:45 -07:00

sysctl.c

Merge commit 'v2.6.28-rc2' into tracing/urgent

2008-10-27 10:50:54 +01:00

taskstats.c

taskstats: remove initialization of static per-cpu variable

2008-07-25 10:53:47 -07:00

test_kprobes.c

kprobes: kretprobe user entry-handler

2008-02-06 10:41:11 -08:00

time.c

select: add a timespec_add_safe() function

2008-09-05 21:34:57 -07:00

timeconst.pl

Make constants in kernel/timeconst.h fixed 64 bits

2008-05-02 16:18:42 -07:00

timer.c

Add round_jiffies_up and related routines

2008-11-06 08:42:48 +01:00

tracepoint.c

tracepoint: check if the probe has been registered

2008-10-27 16:45:46 +01:00

tsacct.c

task IO accounting: move all IO statistics in struct task_io_accounting

2008-07-27 16:12:28 -07:00

uid16.c

asmlinkage_protect replaces prevent_tail_call

2008-04-10 17:28:26 -07:00

user_namespace.c

removed unused #include <linux/version.h>'s

2008-08-23 12:14:12 -07:00

user.c

sched: rt-bandwidth for user grouping interface

2008-08-19 13:10:09 +02:00

utsname_sysctl.c

sysctl: simplify ->strategy

2008-10-16 11:21:47 -07:00

utsname.c

removed unused #include <linux/version.h>'s

2008-08-23 12:14:12 -07:00

wait.c

wait: kill is_sync_wait()

2008-10-16 11:21:31 -07:00

workqueue.c

cpumask: introduce new API, without changing anything

2008-11-06 09:05:33 +01:00