Prateek Sood 75fe5488b2 cgroup: Fix deadlock in cpu hotplug path ... commit 116d2f7496c51b2e02e8e4ecdd2bdf5fb9d5a641 upstream. Deadlock during cgroup migration from cpu hotplug path when a task T is being moved from source to destination cgroup. kworker/0:0 cpuset_hotplug_workfn() cpuset_hotplug_update_tasks() hotplug_update_tasks_legacy() remove_tasks_in_empty_cpuset() cgroup_transfer_tasks() // stuck in iterator loop cgroup_migrate() cgroup_migrate_add_task() In cgroup_migrate_add_task() it checks for PF_EXITING flag of task T. Task T will not migrate to destination cgroup. css_task_iter_start() will keep pointing to task T in loop waiting for task T cg_list node to be removed. Task T do_exit() exit_signals() // sets PF_EXITING exit_task_namespaces() switch_task_namespaces() free_nsproxy() put_mnt_ns() drop_collected_mounts() namespace_unlock() synchronize_rcu() _synchronize_rcu_expedited() schedule_work() // on cpu0 low priority worker pool wait_event() // waiting for work item to execute Task T inserted a work item in the worklist of cpu0 low priority worker pool. It is waiting for expedited grace period work item to execute. This work item will only be executed once kworker/0:0 complete execution of cpuset_hotplug_workfn(). kworker/0:0 ==> Task T ==>kworker/0:0 In case of PF_EXITING task being migrated from source to destination cgroup, migrate next available task in source cgroup. Signed-off-by: Prateek Sood <prsood@codeaurora.org> Signed-off-by: Tejun Heo <tj@kernel.org> [AmitP: Upstream commit cherry-pick failed, so I picked the backported changes from CAF/msm-4.9 tree instead: https://source.codeaurora.org/quic/la/kernel/msm-4.9/commit/?id=49b74f1696417b270c89cd893ca9f37088928078] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2018-10-13 09:11:33 +02:00
..
bpf	bpf: fix references to free_bpf_prog_info() in comments	2018-08-06 16:24:37 +02:00
configs	kconfig: tinyconfig: provide whole choice blocks to avoid warnings	2016-09-24 10:07:42 +02:00
debug	kdb: make "mdr" command repeat	2018-05-30 07:49:17 +02:00
events	perf/core: Fix perf_output_read_group()	2018-05-30 07:49:12 +02:00
gcov	gcov: disable for COMPILE_TEST	2018-01-23 19:50:10 +01:00
irq	genirq: Delay incrementing interrupt count if it's disabled/pending	2018-09-15 09:40:40 +02:00
livepatch	livepatch: x86: fix relocation computation with kASLR	2015-11-11 17:36:04 +01:00
locking	locking/osq_lock: Fix osq_lock queue corruption	2018-09-19 22:48:56 +02:00
power	PM / sleep: wakeup: Fix build error caused by missing SRCU support	2018-09-09 20:04:34 +02:00
printk	braille-console: Fix value returned by _braille_console_setup	2018-03-22 09:23:23 +01:00
rcu	rcu: Allow for page faults in NMI handlers	2017-10-18 09:20:41 +02:00
sched	sched/rt: Fix rq->clock_update_flags < RQCF_ACT_SKIP warning	2018-05-30 07:49:08 +02:00
time	alarmtimer: Prevent overflow for relative nanosleep	2018-10-10 08:52:05 +02:00
trace	ring-buffer: Allow for rescheduling when removing pages	2018-09-29 03:08:52 -07:00
.gitignore	certs: add .gitignore to stop git nagging about x509_certificate_list	2015-10-21 15:18:35 +01:00
acct.c	kernel/acct.c: fix the acct->needcheck check in check_free_space()	2018-01-10 09:27:08 +01:00
async.c	kernel/async.c: revert "async: simplify lowest_in_progress()"	2018-02-16 20:09:45 +01:00
audit.c	audit: return on memory error to avoid null pointer dereference	2018-05-30 07:49:16 +02:00
audit.h	audit: audit_tree_match can be boolean	2015-11-04 08:23:51 -05:00
audit_fsnotify.c	audit: clean simple fsnotify implementation	2015-08-06 16:14:53 -04:00
audit_tree.c	audit: audit_tree_match can be boolean	2015-11-04 08:23:51 -05:00
audit_watch.c	audit: fix use-after-free in audit_add_watch	2018-09-26 08:35:08 +02:00
auditfilter.c	audit: allow not equal op for audit by executable	2018-08-06 16:24:38 +02:00
auditsc.c	audit: allow not equal op for audit by executable	2018-08-06 16:24:38 +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: Fix deadlock in cpu hotplug path	2018-10-13 09:11:33 +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	compat: cleanup coding in compat_get_bitmap() and compat_put_bitmap()	2015-06-04 23:57:18 +02:00
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	kernel/cpu_pm: fix cpu_cluster_pm_exit comment	2015-09-03 02:42:20 +02:00
cpuset.c	sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs	2017-10-12 11:27:35 +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	Remove rest of exec domains.	2015-04-12 21:03:31 +02:00
exit.c	kernel/exit.c: avoid undefined behaviour when calling wait4()	2018-05-26 08:48:51 +02:00
extable.c	kernel/extable.c: mark core_kernel_text notrace	2017-07-21 07:44:56 +02:00
fork.c	kthread: Fix use-after-free if kthread fork fails	2018-09-19 22:48:55 +02:00
freezer.c
futex.c	futex: futex_wake_op, fix sign_extend32 sign bits	2018-05-26 08:48:51 +02:00
futex_compat.c	ptrace: use fsuid, fsgid, effective creds for fs access checks	2016-02-25 12:01:16 -08:00
groups.c	kernel: make groups_sort calling a responsibility group_info allocators	2018-01-10 09:27:10 +01:00
hung_task.c	kernel/hung_task.c: change hung_task.c to use for_each_process_thread()	2015-04-15 16:35:22 -07:00
irq_work.c	treewide: Remove old email address	2015-11-23 09:44:58 +01:00
jump_label.c	jump_label: Invoke jump_label_test() via early_initcall()	2017-12-16 10:33:55 +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	locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS	2015-05-12 09:46:00 +02:00
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	kexec: split kexec_file syscall code to kexec_file.c	2015-09-10 13:29:01 -07:00
kmod.c	kmod: don't run async usermode helper as a child of kworker thread	2015-10-23 17:55:10 +09:00
kprobes.c	kprobes: Make list and blacklist root user read only	2018-09-05 09:18:40 +02:00
ksysfs.c	kexec: split kexec_load syscall from kexec core code	2015-09-10 13:29:01 -07:00
kthread.c	kthread, tracing: Don't expose half-written comm when creating kthreads	2018-09-09 20:04:34 +02:00
latencytop.c
Makefile	sys_membarrier(): system-wide memory barrier (generic, x86)	2015-09-11 15:21:34 -07:00
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: exclude SHN_UNDEF symbols from kallsyms api	2018-10-10 08:52:07 +02:00
module_signing.c	KEYS: Merge the type-specific data with the payload data	2015-10-21 15:18:36 +01:00
notifier.c	Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-09-01 08:40:25 -07:00
nsproxy.c
padata.c	padata: free correct variable	2017-05-20 14:27:02 +02:00
panic.c	kernel/panic.c: add missing \n	2017-07-05 14:37:19 +02:00
params.c	Nothing exciting, minor tweaks and cleanups.	2015-11-09 15:53:39 -08:00
pid.c	pidns: disable pid allocation if pid_ns_prepare_proc() is failed in alloc_pid()	2018-04-13 19:50:03 +02:00
pid_namespace.c	pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes	2017-05-25 14:30:11 +02:00
profile.c	profile: hide unused functions when !CONFIG_PROC_FS	2018-02-25 11:03:44 +01:00
ptrace.c	ptrace: Properly initialize ptracer_cred on fork	2017-06-14 13:16:20 +02:00
range.c
reboot.c	kexec: split kexec_load syscall from kexec core code	2015-09-10 13:29:01 -07:00
relay.c	kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE	2018-05-30 07:49:00 +02:00
resource.c	resource: fix integer overflow at reallocation	2018-04-24 09:32:05 +02:00
seccomp.c	seccomp: Move speculation migitation control to arch code	2018-07-25 10:18:27 +02:00
signal.c	kernel/signal.c: avoid undefined behaviour in kill_something_info	2018-05-30 07:48:52 +02:00
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	stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()	2015-10-20 10:23:55 +02:00
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	sys: don't hold uts_sem while accessing userspace memory	2018-09-09 20:04:35 +02:00
sys_ni.c	mm: mlock: add new mlock system call	2015-11-05 19:34:48 -08:00
sysctl.c	sched/sysctl: Check user input value of sysctl_sched_time_avg	2018-09-05 09:18:33 +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	task_work: remove fifo ordering guarantee	2015-09-05 13:46:58 -07:00
taskstats.c
test_kprobes.c
torture.c	torture: Consolidate cond_resched_rcu_qs() into stutter_wait()	2015-10-06 11:25:01 -07:00
tracepoint.c	tracepoint: Do not warn on ENOMEM	2018-05-16 10:06:47 +02:00
tsacct.c
uid16.c	kernel: make groups_sort calling a responsibility group_info allocators	2018-01-10 09:27:10 +01:00
up.c
user-return-notifier.c
user.c
user_namespace.c	userns: move user access out of the mutex	2018-09-09 20:04:35 +02:00
utsname.c
utsname_sysctl.c	sys: don't hold uts_sem while accessing userspace memory	2018-09-09 20:04:35 +02:00
watchdog.c	kernel/watchdog: use nmi registers snapshot in hardlockup handler	2017-01-06 11:16:16 +01:00
workqueue.c	workqueue: use put_device() instead of kfree()	2018-05-30 07:49:04 +02:00
workqueue_internal.h	workqueue: Fix NULL pointer dereference	2017-11-15 17:13:11 +01:00