Thomas Gleixner 9c388a5ed1 watchdog/harclockup/perf: Revert a33d44843d ("watchdog/hardlockup/perf: Simplify deferred event destroy") ... Guenter reported a crash in the watchdog/perf code, which is caused by cleanup() and enable() running concurrently. The reason for this is: The watchdog functions are serialized via the watchdog_mutex and cpu hotplug locking, but the enable of the perf based watchdog happens in context of the unpark callback of the smpboot thread. But that unpark function is not synchronous inside the locking. The unparking of the thread just wakes it up and leaves so there is no guarantee when the thread is executing. If it starts running _before_ the cleanup happened then it will create a event and overwrite the dead event pointer. The new event is then cleaned up because the event is marked dead. lock(watchdog_mutex); lockup_detector_reconfigure(); cpus_read_lock(); stop(); park() update(); start(); unpark() cpus_read_unlock(); thread runs() overwrite dead event ptr cleanup(); free new event, which is active inside perf.... unlock(watchdog_mutex); The park side is safe as that actually waits for the thread to reach parked state. Commit a33d44843d removed the protection against this kind of scenario under the stupid assumption that the hotplug serialization and the watchdog_mutex cover everything. Bring it back. Reverts: a33d44843d ("watchdog/hardlockup/perf: Simplify deferred event destroy") Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Thomas Feels-stupid Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Don Zickus <dzickus@redhat.com> Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1710312145190.1942@nanos		2017-11-01 21:18:39 +01:00
..
bpf	bpf: rename sk_actions to align with bpf infrastructure	2017-10-29 11:18:48 +09:00
cgroup	Revert "net: defer call to cgroup_sk_alloc()"	2017-10-10 20:24:29 -07:00
configs	ANDROID: binder: add hwbinder,vndbinder to BINDER_DEVICES.	2017-08-22 18:43:23 -07:00
debug	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>	2017-03-02 08:42:34 +01:00
events	perf/core: Fix cgroup time when scheduling descendants	2017-10-10 10:06:55 +02:00
gcov	gcov: support GCC 7.1	2017-05-12 15:57:15 -07:00
irq	irqchip updates for 4.14-rc5	2017-10-16 10:26:46 +02:00
livepatch	livepatch: unpatch all klp_objects if klp_module_coming fails	2017-10-11 15:38:46 +02:00
locking	locking/lockdep: Fix stacktrace mess	2017-10-10 10:04:28 +02:00
power	PM / s2idle: Invoke the ->wake() platform callback earlier	2017-09-29 01:26:13 +02:00
printk	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk	2017-09-07 21:00:52 -07:00
rcu	doc: Fix various RCU docbook comment-header problems	2017-10-19 22:26:11 -04:00
sched	membarrier: Provide register expedited private command	2017-10-19 22:13:40 -04:00
time	drivers/pps: aesthetic tweaks to PPS-related content	2017-09-08 18:26:51 -07:00
trace	Two updates.	2017-10-04 08:34:01 -07:00
.gitignore
acct.c	fs: make the buf argument to __kernel_write a void pointer	2017-09-04 19:05:15 -04:00
async.c	async: Adjust system_state checks	2017-05-23 10:01:37 +02:00
audit_fsnotify.c	Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs	2017-05-03 11:05:15 -07:00
audit_tree.c	Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs	2017-05-03 11:05:15 -07:00
audit_watch.c	audit/stable-4.13 PR 20170816	2017-08-16 16:48:34 -07:00
audit.c	audit: update the function comments	2017-09-05 09:46:59 -04:00
audit.h	ipc: mqueue: Replace timespec with timespec64	2017-09-03 20:21:24 -04:00
auditfilter.c	audit: kernel generated netlink traffic should have a portid of 0	2017-05-02 10:16:05 -04:00
auditsc.c	Merge branch 'work.ipc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2017-09-14 17:37:26 -07:00
backtracetest.c
bounds.c
capability.c
compat.c	semtimedop(): move compat to native	2017-07-15 20:46:47 -04:00
configs.c
context_tracking.c
cpu_pm.c	PM / CPU: replace raw_notifier with atomic_notifier	2017-07-31 13:09:49 +02:00
cpu.c	cpu/hotplug: Reset node state after operation	2017-10-21 16:11:30 +02:00
crash_core.c	kdump: protect vmcoreinfo data under the crash memory	2017-07-12 16:26:00 -07:00
crash_dump.c
cred.c	doc: ReSTify credentials.txt	2017-05-18 10:30:19 -06:00
delayacct.c	sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>	2017-03-02 08:42:39 +01:00
dma.c
elfcore.c
exec_domain.c
exit.c	waitid(): Avoid unbalanced user_access_end() on access_ok() error	2017-10-20 15:32:54 -04:00
extable.c	extable: Enable RCU if it is not watching in kernel_text_address()	2017-09-23 16:50:20 -04:00
fork.c	kmemleak: clear stale pointers from task stacks	2017-10-13 16:18:33 -07:00
freezer.c
futex_compat.c
futex.c	futex: Fix more put_pi_state() vs. exit_pi_state_list() races	2017-11-01 09:05:00 +01:00
groups.c	kernel/groups.c: use sort library function	2017-07-10 16:32:34 -07:00
hung_task.c	kernel/hung_task.c: defer showing held locks	2017-05-08 17:15:10 -07:00
irq_work.c
jump_label.c	jump_label: Provide hotplug context variants	2017-08-10 12:28:59 +02:00
kallsyms.c	kernel/kallsyms.c: replace all_var with IS_ENABLED(CONFIG_KALLSYMS_ALL)	2017-07-10 16:32:34 -07:00
kcmp.c	kernel/kcmp.c: drop branch leftover typo	2017-10-03 17:54:25 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c	kcov: support compat processes	2017-09-08 18:26:51 -07:00
kexec_core.c	x86/mm, kexec: Allow kexec to be used with SME	2017-07-18 11:38:04 +02:00
kexec_file.c	kexec_file: adjust declaration of kexec_purgatory	2017-07-12 16:26:02 -07:00
kexec_internal.h	kexec_file: adjust declaration of kexec_purgatory	2017-07-12 16:26:02 -07:00
kexec.c	kdump: protect vmcoreinfo data under the crash memory	2017-07-12 16:26:00 -07:00
kmod.c	kmod: move #ifdef CONFIG_MODULES wrapper to Makefile	2017-09-08 18:26:51 -07:00
kprobes.c	kprobes: Ensure that jprobe probepoints are at function entry	2017-07-08 11:05:35 +02:00
ksysfs.c	kexec: move vmcoreinfo out of the kernel's .bss section	2017-07-12 16:25:59 -07:00
kthread.c	kernel/kthread.c: kthread_worker: don't hog the cpu	2017-08-31 16:33:15 -07:00
latencytop.c	sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>	2017-03-02 08:42:39 +01:00
Makefile	kmod: move #ifdef CONFIG_MODULES wrapper to Makefile	2017-09-08 18:26:51 -07:00
memremap.c	memremap: add scheduling point to devm_memremap_pages	2017-10-03 17:54:25 -07:00
module_signing.c
module-internal.h
module.c	module: fix ddebug_remove_module()	2017-07-25 15:08:32 +02:00
notifier.c	kernel/notifier.c: simplify expression	2017-02-24 17:46:56 -08:00
nsproxy.c	perf: Add PERF_RECORD_NAMESPACES to include namespaces related info	2017-03-13 15:57:41 -03:00
padata.c	padata: Avoid nested calls to cpus_read_lock() in pcrypt_init_padata()	2017-05-26 10:10:37 +02:00
panic.c	locking/refcounts, x86/asm: Implement fast refcount overflow protection	2017-08-17 10:40:26 +02:00
params.c	kernel/params.c: improve STANDARD_PARAM_DEF readability	2017-10-03 17:54:26 -07:00
pid_namespace.c	userns,pidns: Verify the userns for new pid namespaces	2017-07-20 07:43:58 -05:00
pid.c	pids: make task_tgid_nr_ns() safe	2017-08-21 12:47:31 -07:00
profile.c	sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>	2017-03-02 08:42:39 +01:00
ptrace.c	signal: Remove kernel interal si_code magic	2017-07-24 14:30:28 -05:00
range.c
reboot.c
relay.c	Merge branch 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2017-05-02 11:38:06 -07:00
resource.c
seccomp.c	seccomp: make function __get_seccomp_filter static	2017-10-10 11:45:29 -07:00
signal.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2017-09-11 18:34:47 -07:00
smp.c	treewide: make "nr_cpu_ids" unsigned	2017-09-08 18:26:48 -07:00
smpboot.c	watchdog/core, powerpc: Lock cpus across reconfiguration	2017-10-04 10:53:54 +02:00
smpboot.h
softirq.c	sched/core: Remove 'task' parameter and rename tsk_restore_flags() to current_restore_flags()	2017-04-11 09:06:32 +02:00
stacktrace.c	stacktrace/x86: add function for detecting reliable stack traces	2017-03-08 09:18:02 +01:00
stop_machine.c	stop_machine: Provide stop_machine_cpuslocked()	2017-05-26 10:10:36 +02:00
sys_ni.c
sys.c	prctl: Allow local CAP_SYS_ADMIN changing exe_file	2017-07-20 07:46:07 -05:00
sysctl_binary.c	fs: fix kernel_write prototype	2017-09-04 19:05:15 -04:00
sysctl.c	Merge branch 'core-watchdog-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-10-06 08:36:41 -07:00
task_work.c	task_work: Replace spin_unlock_wait() with lock/unlock pair	2017-07-25 10:08:58 -07:00
taskstats.c	taskstats: add e/u/stime for TGID command	2017-05-08 17:15:12 -07:00
test_kprobes.c
torture.c	torture: Fix typo suppressing CPU-hotplug statistics	2017-07-25 13:04:45 -07:00
tracepoint.c	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>	2017-03-02 08:42:35 +01:00
tsacct.c	sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>	2017-03-02 08:42:39 +01:00
ucount.c	ucount: Remove the atomicity from ucount->count	2017-03-06 15:26:37 -06:00
uid16.c	sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>	2017-03-02 08:42:31 +01:00
umh.c	kmod: split out umh code into its own file	2017-09-08 18:26:50 -07:00
up.c	smp: Avoid using two cache lines for struct call_single_data	2017-08-29 15:14:38 +02:00
user_namespace.c	userns,pidns: Verify the userns for new pid namespaces	2017-07-20 07:43:58 -05:00
user-return-notifier.c
user.c	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h>	2017-03-02 08:42:29 +01:00
utsname_sysctl.c	sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>	2017-03-03 01:45:36 +01:00
utsname.c	sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h>	2017-03-02 08:42:38 +01:00
watchdog_hld.c	watchdog/harclockup/perf: Revert a33d44843d ("watchdog/hardlockup/perf: Simplify deferred event destroy")	2017-11-01 21:18:39 +01:00
watchdog.c	watchdog/core: Put softlockup_threads_initialized under ifdef guard	2017-10-04 11:30:50 +02:00
workqueue_internal.h
workqueue.c	workqueue: replace pool->manager_arb mutex with a flag	2017-10-10 07:13:57 -07:00