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2019-01-27sched/fair: Fix rounding bug for asym packingVincent Guittot
When check_asym_packing() is triggered, the imbalance is set to: busiest_stat.avg_load * busiest_stat.group_capacity / SCHED_CAPACITY_SCALE But busiest_stat.avg_load equals: sgs->group_load * SCHED_CAPACITY_SCALE / sgs->group_capacity These divisions can generate a rounding that will make imbalance slightly lower than the weighted load of the cfs_rq. But this is enough to skip the rq in find_busiest_queue() and prevents asym migration from happening. Directly set imbalance to busiest's sgs->group_load to remove the rounding. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: valentin.schneider@arm.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-27sched/fair: Trigger asym_packing during idle load balanceVincent Guittot
Newly idle load balancing is not always triggered when a CPU becomes idle. This prevents the scheduler from getting a chance to migrate the task for asym packing. Enable active migration during idle load balance too. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: valentin.schneider@arm.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-27sched/fair: Robustify CFS-bandwidth timer lockingPeter Zijlstra
Traditionally hrtimer callbacks were run with IRQs disabled, but with the introduction of HRTIMER_MODE_SOFT it is possible they run from SoftIRQ context, which does _NOT_ have IRQs disabled. Allow for the CFS bandwidth timers (period_timer and slack_timer) to be ran from SoftIRQ context; this entails removing the assumption that IRQs are already disabled from the locking. While mainline doesn't strictly need this, -RT forces all timers not explicitly marked with MODE_HARD into MODE_SOFT and trips over this. And marking these timers as MODE_HARD doesn't make sense as they're not required for RT operation and can potentially be quite expensive. Reported-by: Tom Putzeys <tom.putzeys@be.atlascopco.com> Tested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190107125231.GE14122@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-27sched/core: Give DCE a fighting chancePeter Zijlstra
All that fancy new Energy-Aware scheduling foo is hidden behind a static_key, which is awesome if you have the stuff enabled in your config. However, when you lack all the prerequisites it doesn't make any sense to pretend we'll ever actually run this, so provide a little more clue to the compiler so it can more agressively delete the code. text data bss dec hex filename 50297 976 96 51369 c8a9 defconfig-build/kernel/sched/fair.o 49227 944 96 50267 c45b defconfig-build/kernel/sched/fair.o Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-27sched/topology: Introduce a sysctl for Energy Aware SchedulingQuentin Perret
In its current state, Energy Aware Scheduling (EAS) starts automatically on asymmetric platforms having an Energy Model (EM). However, there are users who want to have an EM (for thermal management for example), but don't want EAS with it. In order to let users disable EAS explicitly, introduce a new sysctl called 'sched_energy_aware'. It is enabled by default so that EAS can start automatically on platforms where it makes sense. Flipping it to 0 rebuilds the scheduling domains and disables EAS. Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: rjw@rjwysocki.net Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-11-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-26bpf: JIT blinds support JMP32Jiong Wang
This patch adds JIT blinds support for JMP32. Like BPF_JMP_REG/IMM, JMP32 version are needed for building raw bpf insn. They are added to both include/linux/filter.h and tools/include/linux/filter.h. Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26bpf: interpreter support for JMP32Jiong Wang
This patch implements interpreting new JMP32 instructions. Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26bpf: disassembler support JMP32Jiong Wang
This patch teaches disassembler about JMP32. There are two places to update: - Class 0x6 now used by BPF_JMP32, not "unused". - BPF_JMP32 need to show comparison operands properly. The disassemble format is to add an extra "(32)" before the operands if it is a sub-register. A better disassemble format for both JMP32 and ALU32 just show the register prefix as "w" instead of "r", this is the format using by LLVM assembler. Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26bpf: verifier support JMP32Jiong Wang
This patch teach verifier about the new BPF_JMP32 instruction class. Verifier need to treat it similar as the existing BPF_JMP class. A BPF_JMP32 insn needs to go through all checks that have been done on BPF_JMP. Also, verifier is doing runtime optimizations based on the extra info conditional jump instruction could offer, especially when the comparison is between constant and register that the value range of the register could be improved based on the comparison results. These code are updated accordingly. Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26bpf: refactor verifier min/max code for condition jumpJiong Wang
The current min/max code does both signed and unsigned comparisons against the input argument "val" which is "u64" and there is explicit type casting when the comparison is signed. As we will need slightly more complexer type casting when JMP32 introduced, it is better to host the signed type casting. This makes the code more clean with ignorable runtime overhead. Also, code for J*GE/GT/LT/LE and JEQ/JNE are very similar, this patch combine them. The main purpose for this refactor is to make sure the min/max code will still be readable and with minimum code duplication after JMP32 introduced. Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25rcuperf: Stop abusing IS_ENABLED()Paul E. McKenney
The ever-evolving IS_ENABLED() macro is intended for CONFIG_* Kconfig options, but rcuperf currently uses it for the decidedly non-CONFIG_* MODULE macro. In the spirit of not inviting trouble, this commit substitutes tried-and-true #ifdef. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org>
2019-01-25rcutorture: Add grace period after CPU offlinePaul E. McKenney
Beyond a certain point in the CPU-hotplug offline process, timers get stranded on the outgoing CPU, and won't fire until that CPU comes back online, which might well be never. This commit therefore adds a hook in torture_onoff_init() that is invoked from torture_offline(), which rcutorture uses to occasionally wait for a grace period. This should result in failures for RCU implementations that rely on stranded timers eventually firing in the absence of the CPU coming back online. Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcutorture: Record grace periods in forward-progress histogramPaul E. McKenney
This commit records grace periods in rcutorture's n_launders_hist[] histogram, thus allowing rcu_torture_fwd_cb_hist() to print out the elapsed number of grace periods between buckets. This information helps to determine whether a lack of forward progress is due to stalled grace periods on the one hand or due to sluggish callback invocation on the other. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25srcu: Remove srcu_queue_delayed_work_on()Sebastian Andrzej Siewior
srcu_queue_delayed_work_on() disables preemption (and therefore CPU hotplug in RCU's case) and then checks based on its own accounting if a CPU is online. If the CPU is online it uses queue_delayed_work_on() otherwise it fallbacks to queue_delayed_work(). The problem here is that queue_work() on -RT does not work with disabled preemption. queue_work_on() works also on an offlined CPU. queue_delayed_work_on() has the problem that it is possible to program a timer on an offlined CPU. This timer will fire once the CPU is online again. But until then, the timer remains programmed and nothing will happen. Add a local timer which will fire (as requested per delay) on the local CPU and then enqueue the work on the specific CPU. RCUtorture testing with SRCU-P for 24h showed no problems. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Fix obsolete DYNTICK_IRQ_NONIDLE commentPaul E. McKenney
This commit updates the DYNTICK_IRQ_NONIDLE header comment to remove the obsolete commentary about unmatched rcu_irq_{enter,exit}(). Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Repair rcu_nmi_exit() docbook headerPaul E. McKenney
This commit removes the "@irq" argument from the rcu_nmi_exit() docbook header, given that this function now has no arguments. Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Remove preemption disabling from expedited CPU selectionPaul E. McKenney
It turns out that it is queue_delayed_work_on() rather than queue_work_on() that has difficulties when used concurrently with CPU-hotplug removal operations. It is therefore unnecessary to protect CPU identification and queue_work_on() with preempt_disable(). This commit therefore removes the preempt_disable() and preempt_enable() from sync_rcu_exp_select_cpus(), which has the further benefit of reducing the number of changes that must be maintained in the -rt patchset. Reported-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: Sebastian Siewior <bigeasy@linutronix.de> Suggested-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Rename rcu_process_callbacks() to rcu_core() for Tree RCUPaul E. McKenney
Although the name rcu_process_callbacks() still makes sense for Tiny RCU, where most of what it does is invoke callbacks, it no longer makes much sense for Tree RCU, especially given that the actually callback invocation is relegated to rcu_do_batch(), or, for no-CBs CPUs, to the rcuo kthreads. Especially in the latter case, rcu_process_callbacks() has very little to do with actual callbacks. A better description of this function is that it performs RCU's core processing. This commit therefore changes the name of Tree RCU's rcu_process_callbacks() function to rcu_core(), which also has the virtue of being consistent with the existing invoke_rcu_core() function. While in the area, the header comment is reworked. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Rename rcu_check_callbacks() to rcu_sched_clock_irq()Paul E. McKenney
The name rcu_check_callbacks() arguably made sense back in the early 2000s when RCU was quite a bit simpler than it is today, but it has become quite misleading, especially with the advent of dyntick-idle and NO_HZ_FULL. The rcu_check_callbacks() function is RCU's hook into the scheduling-clock interrupt, and is now but one of many ways that callbacks get promoted to invocable state. This commit therefore changes the name to rcu_sched_clock_irq(), which is the same number of characters and clearly indicates this function's relation to the rest of the Linux kernel. In addition, for the sake of consistency, rcu_flavor_check_callbacks() is also renamed to rcu_flavor_sched_clock_irq(). While in the area, the header comments for both functions are reworked. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25Merge branches 'consolidate.2019.01.26a' and 'fwd.2019.01.26a' into HEADPaul E. McKenney
consolidate.2019.01.26a: RCU flavor consolidation cleanups. fwd.2019.01.26a: RCU grace-period forward-progress fixes.
2019-01-25rcu: Prevent needless ->gp_seq_needed update in __note_gp_changes()Zhang, Jun
Currently, __note_gp_changes() checks to see if the rcu_node structure's ->gp_seq_needed is greater than or equal to that of the rcu_data structure, and if so, updates the rcu_data structure's ->gp_seq_needed field. This results in a useless store in the case where the two fields are equal. This commit therefore carries out this store only in the case where the rcu_node structure's ->gp_seq_needed is strictly greater than that of the rcu_data structure. Signed-off-by: "Zhang, Jun" <jun.zhang@intel.com> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Link: https://lkml.kernel.org/r/88DC34334CA3444C85D647DBFA962C2735AD5F77@SHSMSX104.ccr.corp.intel.com
2019-01-25rcu: Do RCU GP kthread self-wakeup from softirq and interruptZhang, Jun
The rcu_gp_kthread_wake() function is invoked when it might be necessary to wake the RCU grace-period kthread. Because self-wakeups are normally a useless waste of CPU cycles, if rcu_gp_kthread_wake() is invoked from this kthread, it naturally refuses to do the wakeup. Unfortunately, natural though it might be, this heuristic fails when rcu_gp_kthread_wake() is invoked from an interrupt or softirq handler that interrupted the grace-period kthread just after the final check of the wait-event condition but just before the schedule() call. In this case, a wakeup is required, even though the call to rcu_gp_kthread_wake() is within the RCU grace-period kthread's context. Failing to provide this wakeup can result in grace periods failing to start, which in turn results in out-of-memory conditions. This race window is quite narrow, but it actually did happen during real testing. It would of course need to be fixed even if it was strictly theoretical in nature. This patch does not Cc stable because it does not apply cleanly to earlier kernel versions. Fixes: 48a7639ce80c ("rcu: Make callers awaken grace-period kthread") Reported-by: "He, Bo" <bo.he@intel.com> Co-developed-by: "Zhang, Jun" <jun.zhang@intel.com> Co-developed-by: "He, Bo" <bo.he@intel.com> Co-developed-by: "xiao, jin" <jin.xiao@intel.com> Co-developed-by: Bai, Jie A <jie.a.bai@intel.com> Signed-off: "Zhang, Jun" <jun.zhang@intel.com> Signed-off: "He, Bo" <bo.he@intel.com> Signed-off: "xiao, jin" <jin.xiao@intel.com> Signed-off: Bai, Jie A <jie.a.bai@intel.com> Signed-off-by: "Zhang, Jun" <jun.zhang@intel.com> [ paulmck: Switch from !in_softirq() to "!in_interrupt() && !in_serving_softirq() to avoid redundant wakeups and to also handle the interrupt-handler scenario as well as the softirq-handler scenario that actually occurred in testing. ] Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Link: https://lkml.kernel.org/r/CD6925E8781EFD4D8E11882D20FC406D52A11F61@SHSMSX104.ccr.corp.intel.com
2019-01-25rcu: Add sysrq rcu_node-dump capabilityPaul E. McKenney
Life is hard if RCU manages to get stuck without triggering RCU CPU stall warnings or triggering the rcu_check_gp_start_stall() checks for failing to start a grace period. This commit therefore adds a boot-time-selectable sysrq key (commandeering "y") that allows manually dumping Tree RCU state. The new rcutree.sysrq_rcu kernel boot parameter must be set for this sysrq to be available. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Protect rcu_check_gp_kthread_starvation() access to ->gp_flagsPaul E. McKenney
The rcu_check_gp_kthread_starvation() function can be invoked without holding locks, so the access to the rcu_state structure's ->gp_flags field must be protected with READ_ONCE(). This commit therefore adds this protection. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Improve diagnostics for failed RCU grace-period startPaul E. McKenney
If a grace period fails to start (for example, because you commented out the last two lines of rcu_accelerate_cbs_unlocked()), rcu_core() will invoke rcu_check_gp_start_stall(), which will notice and complain. However, this complaint is lacking crucial debugging information such as when the last wakeup executed and what the value of ->gp_seq was at that time. This commit therefore removes the current pr_alert() from rcu_check_gp_start_stall(), instead invoking show_rcu_gp_kthreads(), which has been updated to print the needed information, which is collected by rcu_gp_kthread_wake(). Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Update NOCB commentsPaul E. McKenney
This commit updates a few obsolete comments in the RCU callback-offload code. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Remove unused rcu_cpu_kthread_cpu per-CPU variablePaul E. McKenney
The rcu_cpu_kthread_cpu used to provide debugfs information, but is no longer used. This commit therefore removes it. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Move rcu_cpu_has_work to rcu_data structurePaul E. McKenney
Given that RCU has a perfectly good per-CPU rcu_data structure, most per-CPU quantities should be stored there. This commit therefore moves the rcu_cpu_has_work per-CPU variable to the rcu_data structure. This also makes this variable unconditionally present, which should be acceptable given the memory reduction due to the RCU flavor consolidation and also due to simplifications this will enable. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Remove unused rcu_cpu_kthread_loops per-CPU variablePaul E. McKenney
The rcu_cpu_kthread_loops variable used to provide debugfs information, but is no longer used. This commit therefore removes it. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Move rcu_cpu_kthread_status to rcu_data structurePaul E. McKenney
Given that RCU has a perfectly good per-CPU rcu_data structure, most per-CPU quantities should be stored there. This commit therefore moves the rcu_cpu_kthread_status per-CPU variable to the rcu_data structure. This also makes this variable unconditionally present, which should be acceptable given the memory reduction due to the RCU flavor consolidation and also due to simplifications this will enable. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Move rcu_cpu_kthread_task to rcu_data structurePaul E. McKenney
Given that RCU has a perfectly good per-CPU rcu_data structure, most per-CPU quantities should be stored there. This commit therefore moves the rcu_cpu_kthread_task per-CPU variable to the rcu_data structure. This also makes this variable unconditionally present, which should be acceptable given the memory reduction due to the RCU flavor consolidation and also due to simplifications this will enable. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Accommodate zero jiffies_till_first_fqs and kthread kickingPaul E. McKenney
It is perfectly fine to set the rcutree.jiffies_till_first_fqs boot parameter to zero, in fact, this can be useful on specialty systems that usually have at least one idle CPU and that need fast grace periods. This is because this setting causes the RCU grace-period kthread to scan for idle threads immediately after grace-period initialization, as opposed to waiting several jiffies to do so. It is also perfectly fine to set the rcutree.rcu_kick_kthreads kernel parameter, which gives the RCU grace-period kthread an extra wakeup if it doesn't make progress for a period of three times the setting of the rcutree.jiffies_till_first_fqs boot parameter. This is of course problematic when the value of this parameter is zero, as it can result in unnecessary wakeup IPIs along with unnecessary WARN_ONCE() invocations. This commit therefore defers kthread kicking for at least two jiffies, regardless of the setting of rcutree.jiffies_till_first_fqs. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Discard separate per-CPU callback countsPaul E. McKenney
Back when there were multiple flavors of RCU, it was necessary to separately count lazy and non-lazy callbacks for each CPU. These counts were used in CONFIG_RCU_FAST_NO_HZ kernels to determine how long a newly idle CPU should be allowed to sleep before handling its RCU callbacks. But now that there is only one flavor, the callback counts for a given CPU's sole rcu_data structure are the counts for that CPU. This commit therefore removes the rcu_data structure's ->nonlazy_posted and ->nonlazy_posted_snap fields, the rcu_idle_count_callbacks_posted() and rcu_cpu_has_callbacks() functions, repurposes the rcu_data structure's ->all_lazy field to record the laziness state at the beginning of the latest idle sojourn, and modifies CONFIG_RCU_FAST_NO_HZ RCU CPU stall warnings accordingly. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Inline _synchronize_rcu_expedited() into synchronize_rcu_expedited()Paul E. McKenney
Now that _synchronize_rcu_expedited() has only one caller, and given that this is a tail call, this commit inlines _synchronize_rcu_expedited() into synchronize_rcu_expedited(). Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Consolidate PREEMPT and !PREEMPT synchronize_rcu()Paul E. McKenney
Now that rcu_blocking_is_gp() makes the correct immediate-return decision for both PREEMPT and !PREEMPT, a single implementation of synchronize_rcu() will work correctly under both configurations. This commit therefore eliminates a few lines of code by consolidating the two implementations of synchronize_rcu(). Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Consolidate PREEMPT and !PREEMPT synchronize_rcu_expedited()Paul E. McKenney
The CONFIG_PREEMPT=n and CONFIG_PREEMPT=y implementations of synchronize_rcu_expedited() are quite similar, and with small modifications to rcu_blocking_is_gp() can be made identical. This commit therefore makes this change in order to save a few lines of code and to reduce the amount of duplicate code. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Determine expedited-GP IPI handler at build timePaul E. McKenney
Back when there could be multiple RCU flavors running in the same kernel at the same time, it was necessary to specify the expedited grace-period IPI handler at runtime. Now that there is only one RCU flavor, the IPI handler can be determined at build time. There is therefore no longer any reason for the RCU-preempt and RCU-sched IPI handlers to have different names, nor is there any reason to pass these handlers in function arguments and in the data structures enclosing workqueues. This commit therefore makes all these changes, pushing the specification of the expedited grace-period IPI handler down to the point of use. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Inline rcu_kthread_do_work() into its sole remaining callerPaul E. McKenney
The rcu_kthread_do_work() function has a single-line body and only one remaining caller. This commit therefore saves a few lines of code by inlining rcu_kthread_do_work() into its sole remaining caller. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Eliminate RCU_BH_FLAVOR and RCU_SCHED_FLAVORPaul E. McKenney
Now that the RCU flavors have been consolidated, RCU_BH_FLAVOR and RCU_SCHED_FLAVOR are no longer used. This commit therefore saves a few lines by removing them. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Inline force_quiescent_state() into rcu_force_quiescent_state()Paul E. McKenney
Given that rcu_force_quiescent_state() is a simple wrapper around force_quiescent_state(), this commit saves a few lines of code by inlining force_quiescent_state() into rcu_force_quiescent_state(), and changing all references to force_quiescent_state() to instead invoke rcu_force_quiescent_state(). Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Make expedited IPI handler return after handling critical sectionPaul E. McKenney
During expedited RCU grace-period initialization, IPIs are sent to all non-idle online CPUs. The IPI handler checks to see if the CPU is in quiescent state, reporting one if so. This handler looks at three different cases: (1) The CPU is not in an rcu_read_lock()-based critical section, (2) The CPU is in the process of exiting an rcu_read_lock()-based critical section, and (3) The CPU is in an rcu_read_lock()-based critical section. In case (2), execution falls through into case (3). This is harmless from a functionality viewpoint, but can result in needless overhead during an improbable corner case. This commit therefore adds the "return" statement needed to prevent fall-through. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25rcu: Rename and comment changes due to only one rcuo kthread per CPUPaul E. McKenney
Given RCU flavor consolidation, the name rcu_spawn_all_nocb_kthreads() is quite misleading. It no longer ever creates more than one kthread, and it does so only for the specified CPU. This commit therefore changes this name to the more descriptive rcu_spawn_cpu_nocb_kthread(), and also fixes up a similar issue in its header comment while in the area. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25sched: Replace synchronize_sched() with synchronize_rcu()Paul E. McKenney
Now that synchronize_rcu() waits for preempt-disable regions of code as well as RCU read-side critical sections, synchronize_sched() can be replaced by synchronize_rcu(), in fact, synchronize_sched() is now completely equivalent to synchronize_rcu(). This commit therefore replaces synchronize_sched() with synchronize_rcu() so that synchronize_sched() can eventually be removed entirely. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
2019-01-25sched: Replace call_rcu_sched() with call_rcu()Paul E. McKenney
Now that call_rcu()'s callback is not invoked until after all preempt-disable regions of code have completed (in addition to explicitly marked RCU read-side critical sections), call_rcu() can be used in place of call_rcu_sched(). This commit therefore makes that change. While in the area, this commit also updates an outdated header comment for for_each_domain(). Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
2019-01-25audit: clean up AUDITSYSCALL prototypes and stubsRichard Guy Briggs
Pull together all the audit syscall watch, mark and tree prototypes and stubs into the same ifdef. Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-25audit: more filter PATH records keyed on filesystem magicRichard Guy Briggs
Like commit 42d5e37654e4 ("audit: filter PATH records keyed on filesystem magic") that addresses https://github.com/linux-audit/audit-kernel/issues/8 Any user or remote filesystem could become unavailable and effectively block on a forced unmount. -a always,exit -S umount2 -F key=umount2 Provide a method to ignore these user and remote filesystems to prevent them from being impossible to unmount. Extend the "AUDIT_FILTER_FS" filter that uses the field type AUDIT_FSTYPE keying off the filesystem 4-octet hexadecimal magic identifier to filter specific filesystems to cover audit_inode() to address this blockage. An example rule would look like: -a never,filesystem -F fstype=0x517B -F key=ignore_smb -a never,filesystem -F fstype=0x6969 -F key=ignore_nfs Arguably the better way to address this issue is to disable auditing processes that touch removable filesystems. Note: refactor __audit_inode_child() to remove two levels of if indentation. Please see the github issue tracker https://github.com/linux-audit/audit-kernel/issues/100 Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-25LSM: add SafeSetID module that gates setid callsMicah Morton
This change ensures that the set*uid family of syscalls in kernel/sys.c (setreuid, setuid, setresuid, setfsuid) all call ns_capable_common with the CAP_OPT_INSETID flag, so capability checks in the security_capable hook can know whether they are being called from within a set*uid syscall. This change is a no-op by itself, but is needed for the proposed SafeSetID LSM. Signed-off-by: Micah Morton <mortonm@chromium.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2019-01-25audit: add support for fcaps v3Richard Guy Briggs
V3 namespaced file capabilities were introduced in commit 8db6c34f1dbc ("Introduce v3 namespaced file capabilities") Add support for these by adding the "frootid" field to the existing fcaps fields in the NAME and BPRM_FCAPS records. Please see github issue https://github.com/linux-audit/audit-kernel/issues/103 Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Acked-by: Serge Hallyn <serge@hallyn.com> [PM: comment tweak to fit an 80 char line width] Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-25audit: move loginuid and sessionid from CONFIG_AUDITSYSCALL to CONFIG_AUDITRichard Guy Briggs
loginuid and sessionid (and audit_log_session_info) should be part of CONFIG_AUDIT scope and not CONFIG_AUDITSYSCALL since it is used in CONFIG_CHANGE, ANOM_LINK, FEATURE_CHANGE (and INTEGRITY_RULE), none of which are otherwise dependent on AUDITSYSCALL. Please see github issue https://github.com/linux-audit/audit-kernel/issues/104 Signed-off-by: Richard Guy Briggs <rgb@redhat.com> [PM: tweaked subject line for better grep'ing] Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-25ipc: rename old-style shmctl/semctl/msgctl syscallsArnd Bergmann
The behavior of these system calls is slightly different between architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION symbol. Most architectures that implement the split IPC syscalls don't set that symbol and only get the modern version, but alpha, arm, microblaze, mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag. For the architectures that so far only implement sys_ipc(), i.e. m68k, mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior when adding the split syscalls, so we need to distinguish between the two groups of architectures. The method I picked for this distinction is to have a separate system call entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl() does not. The system call tables of the five architectures are changed accordingly. As an additional benefit, we no longer need the configuration specific definition for ipc_parse_version(), it always does the same thing now, but simply won't get called on architectures with the modern interface. A small downside is that on architectures that do set ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points that are never called. They only add a few bytes of bloat, so it seems better to keep them compared to adding yet another Kconfig symbol. I considered adding new syscall numbers for the IPC_64 variants for consistency, but decided against that for now. Signed-off-by: Arnd Bergmann <arnd@arndb.de>