Thomas Gleixner 26605a06dd alarmtimer: Rate limit periodic intervals ... commit ff86bf0c65f14346bf2440534f9ba5ac232c39a0 upstream. The alarmtimer code has another source of potentially rearming itself too fast. Interval timers with a very samll interval have a similar CPU hog effect as the previously fixed overflow issue. The reason is that alarmtimers do not implement the normal protection against this kind of problem which the other posix timer use: timer expires -> queue signal -> deliver signal -> rearm timer This scheme brings the rearming under scheduler control and prevents permanently firing timers which hog the CPU. Bringing this scheme to the alarm timer code is a major overhaul because it lacks all the necessary mechanisms completely. So for a quick fix limit the interval to one jiffie. This is not problematic in practice as alarmtimers are usually backed by an RTC for suspend which have 1 second resolution. It could be therefor argued that the resolution of this clock should be set to 1 second in general, but that's outside the scope of this fix. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kostya Serebryany <kcc@google.com> Cc: syzkaller <syzkaller@googlegroups.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Dmitry Vyukov <dvyukov@google.com> Link: http://lkml.kernel.org/r/20170530211655.896767100@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2017-06-26 07:13:11 +02:00
..
bpf	bpf, inode: disallow userns mounts	2016-06-24 10:18:17 -07:00
configs	kconfig: tinyconfig: provide whole choice blocks to avoid warnings	2016-09-24 10:07:42 +02:00
debug	kernel/debug/debug_core.c: more properly delay for secondary CPUs	2017-01-06 11:16:16 +01:00
events	perf/core: Drop kernel samples even though :u is specified	2017-06-14 13:16:25 +02:00
gcov
irq	genirq: Release resources in __setup_irq() error path	2017-06-26 07:13:10 +02:00
livepatch	livepatch: x86: fix relocation computation with kASLR	2015-11-11 17:36:04 +01:00
locking	locking/rtmutex: Use READ_ONCE() in rt_mutex_owner()	2016-12-15 08:49:22 -08:00
power	PM / sleep: fix device reference leak in test_suspend	2016-11-26 09:54:53 +01:00
printk	printk: use rcuidle console tracepoint	2017-02-23 17:43:10 +01:00
rcu	rcu: Fix soft lockup for rcu_nocb_kthread	2016-12-08 07:15:24 +01:00
sched	sched/fair: Initialize throttle_count for new task-groups lazily	2017-05-25 14:30:12 +02:00
time	alarmtimer: Rate limit periodic intervals	2017-06-26 07:13:11 +02:00
trace	tracing/kprobes: Enforce kprobes teardown after testing	2017-05-25 14:30:17 +02:00
.gitignore
acct.c
async.c
audit.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
audit.h	audit: audit_tree_match can be boolean	2015-11-04 08:23:51 -05:00
audit_fsnotify.c
audit_tree.c	audit: audit_tree_match can be boolean	2015-11-04 08:23:51 -05:00
audit_watch.c	audit: fix exe_file access in audit_exe_compare	2016-09-24 10:07:36 +02:00
auditfilter.c	audit: fix comment block whitespace	2015-11-04 08:23:51 -05:00
auditsc.c	audit: fix a double fetch in audit_log_single_execve_arg()	2016-08-20 18:09:22 +02:00
backtracetest.c
bounds.c
capability.c	exec: Ensure mm->user_ns contains the execed files	2017-01-06 11:16:14 +01:00
cgroup.c	cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups	2017-04-21 09:30:04 +02:00
cgroup_freezer.c	cgroup: fix handling of multi-destination migration from subtree_control enabling	2015-12-03 10:18:21 -05:00
cgroup_pids.c	cgroup_pids: don't account for the root cgroup	2015-12-03 10:18:21 -05:00
compat.c
configs.c
context_tracking.c	context_tracking: avoid irq_save/irq_restore on guest entry and exit	2015-11-10 12:06:23 +01:00
cpu.c	stable-fixup: hotplug: fix unused function warning	2017-01-12 11:22:48 +01:00
cpu_pm.c
cpuset.c	cpuset: consider dying css as offline	2017-06-14 13:16:23 +02:00
crash_dump.c
cred.c	cred: Reject inodes with invalid ids in set_create_file_as()	2016-09-15 08:27:49 +02:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	wait/ptrace: assume __WALL if the child is traced	2016-06-07 18:14:35 -07:00
extable.c
fork.c	stackprotector: Increase the per-task stack canary's random range from 32 bits to 64 bits on 64-bit platforms	2017-06-14 13:16:23 +02:00
freezer.c
futex.c	futex: Add missing error handling to FUTEX_REQUEUE_PI	2017-03-22 12:04:19 +01:00
futex_compat.c	ptrace: use fsuid, fsgid, effective creds for fs access checks	2016-02-25 12:01:16 -08:00
groups.c
hung_task.c
irq_work.c	treewide: Remove old email address	2015-11-23 09:44:58 +01:00
jump_label.c	jump_labels: API for flushing deferred jump label updates	2017-01-19 20:17:19 +01:00
kallsyms.c
kcmp.c	ptrace: use fsuid, fsgid, effective creds for fs access checks	2016-02-25 12:01:16 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c	kexec: use file name as the output message prefix	2015-11-06 17:50:42 -08:00
kexec_core.c	kexec: use file name as the output message prefix	2015-11-06 17:50:42 -08:00
kexec_file.c	kexec: fix double-free when failing to relocate the purgatory	2016-09-24 10:07:36 +02:00
kexec_internal.h
kmod.c
kprobes.c	tracing/kprobes: Enforce kprobes teardown after testing	2017-05-25 14:30:17 +02:00
ksysfs.c
kthread.c	cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups	2017-04-21 09:30:04 +02:00
latencytop.c
Makefile
membarrier.c	Fix: Disable sys_membarrier when nohz_full is enabled	2017-03-12 06:37:26 +01:00
memremap.c	mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}	2017-01-19 20:17:18 +01:00
module-internal.h
module.c	module: Invalidate signatures on force-loaded modules	2016-08-20 18:09:27 +02:00
module_signing.c
notifier.c
nsproxy.c
padata.c	padata: free correct variable	2017-05-20 14:27:02 +02:00
panic.c	printk: do cond_resched() between lines while outputting to consoles	2016-02-17 12:30:57 -08:00
params.c	Nothing exciting, minor tweaks and cleanups.	2015-11-09 15:53:39 -08:00
pid.c	pidns: fix NULL dereference in __task_pid_nr_ns()	2015-11-24 12:03:55 -08:00
pid_namespace.c	pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes	2017-05-25 14:30:11 +02:00
profile.c
ptrace.c	ptrace: Properly initialize ptracer_cred on fork	2017-06-14 13:16:20 +02:00
range.c
reboot.c
relay.c
resource.c	kernel/resource.c: fix muxed resource handling in __request_region()	2016-03-03 15:07:29 -08:00
seccomp.c	seccomp: always propagate NO_NEW_PRIVS on tsync	2016-03-03 15:07:25 -08:00
signal.c	kernel/signal.c: unexport sigsuspend()	2015-11-20 16:17:32 -08:00
smp.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c	kernel: remove stop_machine() Kconfig dependency	2015-12-12 10:15:34 -08:00
sys.c	prctl: take mmap sem for writing to protect against others	2016-02-25 12:01:25 -08:00
sys_ni.c	mm: mlock: add new mlock system call	2015-11-05 19:34:48 -08:00
sysctl.c	mnt: Add a per mount namespace limit on the number of mounts	2017-04-30 05:49:28 +02:00
sysctl_binary.c	fs/coredump: prevent fsuid=0 dumps into user-controlled directories	2016-04-12 09:08:58 -07:00
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
watchdog.c	kernel/watchdog: use nmi registers snapshot in hardlockup handler	2017-01-06 11:16:16 +01:00
workqueue.c	workqueue: fix rebind bound workers warning	2016-05-18 17:06:50 -07:00
workqueue_internal.h