26c4caea9d
Currently a single process may register exit handlers unlimited times. It may lead to a bloated listeners chain and very slow process terminations. Eg after 10KK sent TASKSTATS_CMD_ATTR_REGISTER_CPUMASKs ~300 Mb of kernel memory is stolen for the handlers chain and "time id" shows 2-7 seconds instead of normal 0.003. It makes it possible to exhaust all kernel memory and to eat much of CPU time by triggerring numerous exits on a single CPU. The patch limits the number of times a single process may register itself on a single CPU to one. One little issue is kept unfixed - as taskstats_exit() is called before exit_files() in do_exit(), the orphaned listener entry (if it was not explicitly deregistered) is kept until the next someone's exit() and implicit deregistration in send_cpu_listeners(). So, if a process registered itself as a listener exits and the next spawned process gets the same pid, it would inherit taskstats attributes. Signed-off-by: Vasiliy Kulikov <segooon@gmail.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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.. | ||
debug | ||
events | ||
gcov | ||
irq | ||
power | ||
time | ||
trace | ||
.gitignore | ||
acct.c | ||
async.c | ||
audit.c | ||
audit.h | ||
audit_tree.c | ||
audit_watch.c | ||
auditfilter.c | ||
auditsc.c | ||
backtracetest.c | ||
bounds.c | ||
capability.c | ||
cgroup.c | ||
cgroup_freezer.c | ||
compat.c | ||
configs.c | ||
cpu.c | ||
cpuset.c | ||
crash_dump.c | ||
cred.c | ||
delayacct.c | ||
dma.c | ||
elfcore.c | ||
exec_domain.c | ||
exit.c | ||
extable.c | ||
fork.c | ||
freezer.c | ||
futex.c | ||
futex_compat.c | ||
groups.c | ||
hrtimer.c | ||
hung_task.c | ||
irq_work.c | ||
itimer.c | ||
jump_label.c | ||
kallsyms.c | ||
Kconfig.freezer | ||
Kconfig.hz | ||
Kconfig.locks | ||
Kconfig.preempt | ||
kexec.c | ||
kfifo.c | ||
kmod.c | ||
kprobes.c | ||
ksysfs.c | ||
kthread.c | ||
latencytop.c | ||
lockdep.c | ||
lockdep_internals.h | ||
lockdep_proc.c | ||
lockdep_states.h | ||
Makefile | ||
module.c | ||
mutex-debug.c | ||
mutex-debug.h | ||
mutex.c | ||
mutex.h | ||
notifier.c | ||
nsproxy.c | ||
padata.c | ||
panic.c | ||
params.c | ||
pid.c | ||
pid_namespace.c | ||
pm_qos_params.c | ||
posix-cpu-timers.c | ||
posix-timers.c | ||
printk.c | ||
profile.c | ||
ptrace.c | ||
range.c | ||
rcupdate.c | ||
rcutiny.c | ||
rcutiny_plugin.h | ||
rcutorture.c | ||
rcutree.c | ||
rcutree.h | ||
rcutree_plugin.h | ||
rcutree_trace.c | ||
relay.c | ||
res_counter.c | ||
resource.c | ||
rtmutex-debug.c | ||
rtmutex-debug.h | ||
rtmutex-tester.c | ||
rtmutex.c | ||
rtmutex.h | ||
rtmutex_common.h | ||
rwsem.c | ||
sched.c | ||
sched_autogroup.c | ||
sched_autogroup.h | ||
sched_clock.c | ||
sched_cpupri.c | ||
sched_cpupri.h | ||
sched_debug.c | ||
sched_fair.c | ||
sched_features.h | ||
sched_idletask.c | ||
sched_rt.c | ||
sched_stats.h | ||
sched_stoptask.c | ||
seccomp.c | ||
semaphore.c | ||
signal.c | ||
smp.c | ||
softirq.c | ||
spinlock.c | ||
srcu.c | ||
stacktrace.c | ||
stop_machine.c | ||
sys.c | ||
sys_ni.c | ||
sysctl.c | ||
sysctl_binary.c | ||
sysctl_check.c | ||
taskstats.c | ||
test_kprobes.c | ||
time.c | ||
timeconst.pl | ||
timer.c | ||
tracepoint.c | ||
tsacct.c | ||
uid16.c | ||
up.c | ||
user-return-notifier.c | ||
user.c | ||
user_namespace.c | ||
utsname.c | ||
utsname_sysctl.c | ||
wait.c | ||
watchdog.c | ||
workqueue.c | ||
workqueue_sched.h |