BMC/Intel-BMC/linux.git/kernel/time/posix-cpu-timers.c, branch dev-5.2

posix-cpu-timers: Remove private interval storage

2019-01-15T15:36:13+00:00

Posix CPU timers store the interval in private storage for historical reasons (it_interval used to be a non scalar representation on 32bit systems). This is gone and there is no reason for duplicated storage anymore. Use it_interval everywhere. Signed-off-by: Thomas Gleixner Cc: John Stultz Cc: Peter Zijlstra Cc: "H.J. Lu" Link: https://lkml.kernel.org/r/20190111133500.945255655@linutronix.de

posix-cpu-timers: Unbreak timer rearming

2019-01-15T15:34:37+00:00

The recent commit which prevented a division by 0 issue in the alarm timer code broke posix CPU timers as an unwanted side effect. The reason is that the common rearm code checks for timer->it_interval being 0 now. What went unnoticed is that the posix cpu timer setup does not initialize timer->it_interval as it stores the interval in CPU timer specific storage. The reason for the separate storage is historical as the posix CPU timers always had a 64bit nanoseconds representation internally while timer->it_interval is type ktime_t which used to be a modified timespec representation on 32bit machines. Instead of reverting the offending commit and fixing the alarmtimer issue in the alarmtimer code, store the interval in timer->it_interval at CPU timer setup time so the common code check works. This also repairs the existing inconistency of the posix CPU timer code which kept a single shot timer armed despite of the interval being 0. The separate storage can be removed in mainline, but that needs to be a separate commit as the current one has to be backported to stable kernels. Fixes: 0e334db6bb4b ("posix-timers: Fix division by zero bug") Reported-by: H.J. Lu Signed-off-by: Thomas Gleixner Cc: John Stultz Cc: Peter Zijlstra Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190111133500.840117406@linutronix.de

posix-cpu-timers: Remove useless call to check_dl_overrun()

2018-11-08T06:43:35+00:00

check_dl_overrun() is used to send a SIGXCPU to users that asked to be informed when a SCHED_DEADLINE runtime overruns occur. The function is called by check_thread_timers() already, so the call in check_process_timers() is redundant/wrong (even though harmless). Remove it. Fixes: 34be39305a77 ("sched/deadline: Implement "runtime overrun signal" support") Signed-off-by: Juri Lelli Signed-off-by: Thomas Gleixner Reviewed-by: Daniel Bristot de Oliveira Reviewed-by: Steven Rostedt (VMware) Cc: linux-rt-users@vger.kernel.org Cc: mtk.manpages@gmail.com Cc: Mathieu Poirier Cc: Peter Zijlstra Cc: Luca Abeni Cc: Claudio Scordino Link: https://lkml.kernel.org/r/20181107111032.32291-1-juri.lelli@redhat.com

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

2018-08-21T20:47:29+00:00

Pull core signal handling updates from Eric Biederman: "It was observed that a periodic timer in combination with a sufficiently expensive fork could prevent fork from every completing. This contains the changes to remove the need for that restart. This set of changes is split into several parts: - The first part makes PIDTYPE_TGID a proper pid type instead something only for very special cases. The part starts using PIDTYPE_TGID enough so that in __send_signal where signals are actually delivered we know if the signal is being sent to a a group of processes or just a single process. - With that prep work out of the way the logic in fork is modified so that fork logically makes signals received while it is running appear to be received after the fork completes" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits) signal: Don't send signals to tasks that don't exist signal: Don't restart fork when signals come in. fork: Have new threads join on-going signal group stops fork: Skip setting TIF_SIGPENDING in ptrace_init_task signal: Add calculate_sigpending() fork: Unconditionally exit if a fatal signal is pending fork: Move and describe why the code examines PIDNS_ADDING signal: Push pid type down into complete_signal. signal: Push pid type down into __send_signal signal: Push pid type down into send_signal signal: Pass pid type into do_send_sig_info signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task signal: Pass pid type into group_send_sig_info signal: Pass pid and pid type into send_sigqueue posix-timers: Noralize good_sigevent signal: Use PIDTYPE_TGID to clearly store where file signals will be sent pid: Implement PIDTYPE_TGID pids: Move the pgrp and session pid pointers from task_struct to signal_struct kvm: Don't open code task_pid in kvm_vcpu_ioctl pids: Compute task_tgid using signal->leader_pid ...

pid: Implement PIDTYPE_TGID

2018-07-21T15:43:12+00:00

Everywhere except in the pid array we distinguish between a tasks pid and a tasks tgid (thread group id). Even in the enumeration we want that distinction sometimes so we have added __PIDTYPE_TGID. With leader_pid we almost have an implementation of PIDTYPE_TGID in struct signal_struct. Add PIDTYPE_TGID as a first class member of the pid_type enumeration and into the pids array. Then remove the __PIDTYPE_TGID special case and the leader_pid in signal_struct. The net size increase is just an extra pointer added to struct pid and an extra pair of pointers of an hlist_node added to task_struct. The effect on code maintenance is the removal of a number of special cases today and the potential to remove many more special cases as PIDTYPE_TGID gets used to it's fullest. The long term potential is allowing zombie thread group leaders to exit, which will remove a lot more special cases in the code. Signed-off-by: "Eric W. Biederman"

Merge branch 'fortglx/4.19/time' of https://git.linaro.org/people/john.stultz/linux into timers/core

2018-07-12T20:19:58+00:00

Pull timekeeping updates from John Stultz: - Make the timekeeping update more precise when NTP frequency is set directly by updating the multiplier. - Adjust selftests

posix-timers: Sanitize overrun handling

2018-07-02T09:33:25+00:00

The posix timer overrun handling is broken because the forwarding functions can return a huge number of overruns which does not fit in an int. As a consequence timer_getoverrun(2) and siginfo::si_overrun can turn into random number generators. The k_clock::timer_forward() callbacks return a 64 bit value now. Make k_itimer::ti_overrun[_last] 64bit as well, so the kernel internal accounting is correct. 3Remove the temporary (int) casts. Add a helper function which clamps the overrun value returned to user space via timer_getoverrun(2) or siginfo::si_overrun limited to a positive value between 0 and INT_MAX. INT_MAX is an indicator for user space that the overrun value has been clamped. Reported-by: Team OWL337 Signed-off-by: Thomas Gleixner Acked-by: John Stultz Cc: Peter Zijlstra Cc: Michael Kerrisk Link: https://lkml.kernel.org/r/20180626132705.018623573@linutronix.de

posix-cpu-timers: Remove lockdep_assert_irqs_disabled()

2018-06-12T15:18:37+00:00

The lockdep_assert_irqs_disabled() was a BUG_ON() statement in the beginning and it was added just before the "spin_lock(siglock)" statement to ensure this lock was taken with disabled interrupts. This is no longer the case: the siglock is acquired via lock_task_sighand() and this function already disables the interrupts. The lock is also acquired before this "lockdep_assert_irqs_disabled" so it is best to remove it. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Frederic Weisbecker Link: https://lkml.kernel.org/r20180504152548.7166-1-bigeasy@linutronix.de

posix-cpu-timers: Ensure set_process_cpu_timer is always evaluated

2018-04-19T10:54:57+00:00

Commit a9445e47d897 ("posix-cpu-timers: Make set_process_cpu_timer() more robust") moved the check into the 'if' statement. Unfortunately, it did so on the right side of an && which means that it may get short circuited and never evaluated. This is easily reproduced with: $ cat loop.c void main() { struct rlimit res; /* set the CPU time limit */ getrlimit(RLIMIT_CPU,&res); res.rlim_cur = 2; res.rlim_max = 2; setrlimit(RLIMIT_CPU,&res); while (1); } Which will hang forever instead of being killed. Fix this by pulling the evaluation out of the if statement but checking the return value instead. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1568337 Fixes: a9445e47d897 ("posix-cpu-timers: Make set_process_cpu_timer() more robust") Signed-off-by: Laura Abbott Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Cc: "Max R . P . Grossmann" Cc: John Stultz Link: https://lkml.kernel.org/r/20180417215742.2521-1-labbott@redhat.com

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

2018-01-30T19:55:56+00:00

Pull scheduler updates from Ingo Molnar: "The main changes in this cycle were: - Implement frequency/CPU invariance and OPP selection for SCHED_DEADLINE (Juri Lelli) - Tweak the task migration logic for better multi-tasking workload scalability (Mel Gorman) - Misc cleanups, fixes and improvements" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/deadline: Make bandwidth enforcement scale-invariant sched/cpufreq: Move arch_scale_{freq,cpu}_capacity() outside of #ifdef CONFIG_SMP sched/cpufreq: Remove arch_scale_freq_capacity()'s 'sd' parameter sched/cpufreq: Always consider all CPUs when deciding next freq sched/cpufreq: Split utilization signals sched/cpufreq: Change the worker kthread to SCHED_DEADLINE sched/deadline: Move CPU frequency selection triggering points sched/cpufreq: Use the DEADLINE utilization signal sched/deadline: Implement "runtime overrun signal" support sched/fair: Only immediately migrate tasks due to interrupts if prev and target CPUs share cache sched/fair: Correct obsolete comment about cpufreq_update_util() sched/fair: Remove impossible condition from find_idlest_group_cpu() sched/cpufreq: Don't pass flags to sugov_set_iowait_boost() sched/cpufreq: Initialize sg_cpu->flags to 0 sched/fair: Consider RT/IRQ pressure in capacity_spare_wake() sched/fair: Use 'unsigned long' for utilization, consistently sched/core: Rework and clarify prepare_lock_switch() sched/fair: Remove unused 'curr' parameter from wakeup_gran sched/headers: Constify object_is_on_stack()