user/sven/linux.git/kernel/sched, branch v3.15.3

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

2014-06-06T16:53:32Z

Pull scheduler fixes from Ingo Molnar: "Four misc fixes: each was deemed serious enough to warrant v3.15 inclusion" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Fix tg_set_cfs_bandwidth() deadlock on rq->lock sched/dl: Fix race in dl_task_timer() sched: Fix sched_policy < 0 comparison sched/numa: Fix use of spin_{un}lock_irq() when interrupts are disabled

sched/fair: Fix tg_set_cfs_bandwidth() deadlock on rq->lock

2014-06-05T09:51:34Z

tg_set_cfs_bandwidth() sets cfs_b->timer_active to 0 to force the period timer restart. It's not safe, because can lead to deadlock, described in commit 927b54fccbf0: "__start_cfs_bandwidth calls hrtimer_cancel while holding rq->lock, waiting for the hrtimer to finish. However, if sched_cfs_period_timer runs for another loop iteration, the hrtimer can attempt to take rq->lock, resulting in deadlock." Three CPUs must be involved: CPU0 CPU1 CPU2 take rq->lock period timer fired ... take cfs_b lock ... ... tg_set_cfs_bandwidth() throttle_cfs_rq() release cfs_b lock take cfs_b lock ... distribute_cfs_runtime() timer_active = 0 take cfs_b->lock wait for rq->lock ... __start_cfs_bandwidth() {wait for timer callback break if timer_active == 1} So, CPU0 and CPU1 are deadlocked. Instead of resetting cfs_b->timer_active, tg_set_cfs_bandwidth can wait for period timer callbacks (ignoring cfs_b->timer_active) and restart the timer explicitly. Signed-off-by: Roman Gushchin Reviewed-by: Ben Segall Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/87wqdi9g8e.wl\%klamm@yandex-team.ru Cc: pjt@google.com Cc: chris.j.arges@canonical.com Cc: gregkh@linuxfoundation.org Cc: Linus Torvalds Signed-off-by: Ingo Molnar

sched/dl: Fix race in dl_task_timer()

2014-06-05T09:51:12Z

Throttled task is still on rq, and it may be moved to other cpu if user is playing with sched_setaffinity(). Therefore, unlocked task_rq() access makes the race. Juri Lelli reports he got this race when dl_bandwidth_enabled() was not set. Other thing, pointed by Peter Zijlstra: "Now I suppose the problem can still actually happen when you change the root domain and trigger a effective affinity change that way". To fix that we do the same as made in __task_rq_lock(). We do not use __task_rq_lock() itself, because it has a useful lockdep check, which is not correct in case of dl_task_timer(). We do not need pi_lock locked here. This case is an exception (PeterZ): "The only reason we don't strictly need ->pi_lock now is because we're guaranteed to have p->state == TASK_RUNNING here and are thus free of ttwu races". Signed-off-by: Kirill Tkhai Signed-off-by: Peter Zijlstra Cc: # v3.14+ Cc: Linus Torvalds Link: http://lkml.kernel.org/r/3056991400578422@web14g.yandex.ru Signed-off-by: Ingo Molnar

sched: Fix sched_policy < 0 comparison

2014-06-05T09:07:43Z

attr.sched_policy is u32, therefore a comparison against < 0 is never true. Fix this by casting sched_policy to int. This issue was reported by coverity CID 1219934. Fixes: dbdb22754fde ("sched: Disallow sched_attr::sched_policy < 0") Signed-off-by: Richard Weinberger Signed-off-by: Peter Zijlstra Cc: Michael Kerrisk Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1401741514-7045-1-git-send-email-richard@nod.at Signed-off-by: Ingo Molnar

sched/numa: Fix use of spin_{un}lock_irq() when interrupts are disabled

2014-06-05T09:07:41Z

As Peter Zijlstra told me, we have the following path: do_exit() exit_itimers() itimer_delete() spin_lock_irqsave(&timer->it_lock, &flags); timer_delete_hook(timer); kc->timer_del(timer) := posix_cpu_timer_del() put_task_struct() __put_task_struct() task_numa_free() spin_lock(&grp->lock); Which means that task_numa_free() can be called with interrupts disabled, which means that we should not be using spin_lock_irq() but spin_lock_irqsave() instead. Otherwise we are enabling interrupts while holding an interrupt unsafe lock! Signed-off-by: Steven Rostedt Signed-off-by: Peter Zijlstra Cc: Thomas Gleixner Cc: Mike Galbraith Cc: Eric Dumazet Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20140527182541.GH11096@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar

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

2014-06-02T01:26:59Z

Pull scheduler fixes from Ingo Molnar: "Various fixlets, mostly related to the (root-only) SCHED_DEADLINE policy, but also a hotplug bug fix and a fix for a NR_CPUS related overallocation bug causing a suspend/resume regression" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Fix hotplug vs. set_cpus_allowed_ptr() sched/cpupri: Replace NR_CPUS arrays sched/deadline: Replace NR_CPUS arrays sched/deadline: Restrict user params max value to 2^63 ns sched/deadline: Change sched_getparam() behaviour vs SCHED_DEADLINE sched: Disallow sched_attr::sched_policy < 0 sched: Make sched_setattr() correctly return -EFBIG

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

2014-05-23T17:04:04Z

Pull scheduler fixes from Ingo Molnar: "The biggest commit is an irqtime accounting loop latency fix, the rest are misc fixes all over the place: deadline scheduling, docs, numa, balancer and a bad to-idle latency fix" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/numa: Initialize newidle balance stats in sd_numa_init() sched: Fix updating rq->max_idle_balance_cost and rq->next_balance in idle_balance() sched: Skip double execution of pick_next_task_fair() sched: Use CPUPRI_NR_PRIORITIES instead of MAX_RT_PRIO in cpupri check sched/deadline: Fix memory leak sched/deadline: Fix sched_yield() behavior sched: Sanitize irq accounting madness sched/docbook: Fix 'make htmldocs' warnings caused by missing description

sched: Fix hotplug vs. set_cpus_allowed_ptr()

2014-05-22T08:21:31Z

Lai found that: WARNING: CPU: 1 PID: 13 at arch/x86/kernel/smp.c:124 native_smp_send_reschedule+0x2d/0x4b() ... migration_cpu_stop+0x1d/0x22 was caused by set_cpus_allowed_ptr() assuming that cpu_active_mask is always a sub-set of cpu_online_mask. This isn't true since 5fbd036b552f ("sched: Cleanup cpu_active madness"). So set active and online at the same time to avoid this particular problem. Fixes: 5fbd036b552f ("sched: Cleanup cpu_active madness") Signed-off-by: Lai Jiangshan Signed-off-by: Peter Zijlstra Cc: Andrew Morton Cc: Gautham R. Shenoy Cc: Linus Torvalds Cc: Michael wang Cc: Paul Gortmaker Cc: Rafael J. Wysocki Cc: Srivatsa S. Bhat Cc: Toshi Kani Link: http://lkml.kernel.org/r/53758B12.8060609@cn.fujitsu.com Signed-off-by: Ingo Molnar

sched/cpupri: Replace NR_CPUS arrays

2014-05-22T08:21:29Z

Tejun reported that his resume was failing due to order-3 allocations from sched_domain building. Replace the NR_CPUS arrays in there with a dynamically allocated array. Reported-by: Tejun Heo Signed-off-by: Peter Zijlstra Cc: Johannes Weiner Cc: Steven Rostedt Cc: Linus Torvalds Link: http://lkml.kernel.org/n/tip-7cysnkw1gik45r864t1nkudh@git.kernel.org Signed-off-by: Ingo Molnar

sched/deadline: Replace NR_CPUS arrays

2014-05-22T08:21:28Z

Tejun reported that his resume was failing due to order-3 allocations from sched_domain building. Replace the NR_CPUS arrays in there with a dynamically allocated array. Reported-by: Tejun Heo Signed-off-by: Peter Zijlstra Acked-by: Juri Lelli Cc: Johannes Weiner Cc: Linus Torvalds Link: http://lkml.kernel.org/n/tip-kat4gl1m5a6dwy6nzuqox45e@git.kernel.org Signed-off-by: Ingo Molnar