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
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.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
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
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.c
cpu/hotplug: Reset node state after operation
2017-10-21 16:11:30 +02:00
cpu_pm.c
PM / CPU: replace raw_notifier with atomic_notifier
2017-07-31 13:09:49 +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
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.c
futex: Fix more put_pi_state() vs. exit_pi_state_list() races
2017-11-01 09:05:00 +01:00
futex_compat.c
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.c
kdump: protect vmcoreinfo data under the crash memory
2017-07-12 16:26:00 -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
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
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-internal.h
module.c
module: fix ddebug_remove_module()
2017-07-25 15:08:32 +02:00
module_signing.c
notifier.c
nsproxy.c
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.c
pids: make task_tgid_nr_ns() safe
2017-08-21 12:47:31 -07:00
pid_namespace.c
userns,pidns: Verify the userns for new pid namespaces
2017-07-20 07:43:58 -05:00
profile.c
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
stop_machine.c
stop_machine: Provide stop_machine_cpuslocked()
2017-05-26 10:10:36 +02:00
sys.c
prctl: Allow local CAP_SYS_ADMIN changing exe_file
2017-07-20 07:46:07 -05:00
sys_ni.c
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
sysctl_binary.c
fs: fix kernel_write prototype
2017-09-04 19:05:15 -04:00
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
tsacct.c
ucount.c
uid16.c
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-return-notifier.c
user.c
user_namespace.c
userns,pidns: Verify the userns for new pid namespaces
2017-07-20 07:43:58 -05:00
utsname.c
utsname_sysctl.c
watchdog.c
watchdog/core: Put softlockup_threads_initialized under ifdef guard
2017-10-04 11:30:50 +02:00
watchdog_hld.c
watchdog/harclockup/perf: Revert a33d44843d ("watchdog/hardlockup/perf: Simplify deferred event destroy")
2017-11-01 21:18:39 +01:00
workqueue.c
workqueue: replace pool->manager_arb mutex with a flag
2017-10-10 07:13:57 -07:00
workqueue_internal.h