Michal Hocko 777c6e0dae hotplug: Make register and unregister notifier API symmetric ... Yu Zhao has noticed that __unregister_cpu_notifier only unregisters its notifiers when HOTPLUG_CPU=y while the registration might succeed even when HOTPLUG_CPU=n if MODULE is enabled. This means that e.g. zswap might keep a stale notifier on the list on the manual clean up during the pool tear down and thus corrupt the list. Resulting in the following [ 144.964346] BUG: unable to handle kernel paging request at ffff880658a2be78 [ 144.971337] IP: [<ffffffffa290b00b>] raw_notifier_chain_register+0x1b/0x40 <snipped> [ 145.122628] Call Trace: [ 145.125086] [<ffffffffa28e5cf8>] __register_cpu_notifier+0x18/0x20 [ 145.131350] [<ffffffffa2a5dd73>] zswap_pool_create+0x273/0x400 [ 145.137268] [<ffffffffa2a5e0fc>] __zswap_param_set+0x1fc/0x300 [ 145.143188] [<ffffffffa2944c1d>] ? trace_hardirqs_on+0xd/0x10 [ 145.149018] [<ffffffffa2908798>] ? kernel_param_lock+0x28/0x30 [ 145.154940] [<ffffffffa2a3e8cf>] ? __might_fault+0x4f/0xa0 [ 145.160511] [<ffffffffa2a5e237>] zswap_compressor_param_set+0x17/0x20 [ 145.167035] [<ffffffffa2908d3c>] param_attr_store+0x5c/0xb0 [ 145.172694] [<ffffffffa290848d>] module_attr_store+0x1d/0x30 [ 145.178443] [<ffffffffa2b2b41f>] sysfs_kf_write+0x4f/0x70 [ 145.183925] [<ffffffffa2b2a5b9>] kernfs_fop_write+0x149/0x180 [ 145.189761] [<ffffffffa2a99248>] __vfs_write+0x18/0x40 [ 145.194982] [<ffffffffa2a9a412>] vfs_write+0xb2/0x1a0 [ 145.200122] [<ffffffffa2a9a732>] SyS_write+0x52/0xa0 [ 145.205177] [<ffffffffa2ff4d97>] entry_SYSCALL_64_fastpath+0x12/0x17 This can be even triggered manually by changing /sys/module/zswap/parameters/compressor multiple times. Fix this issue by making unregister APIs symmetric to the register so there are no surprises. Fixes: 47e627bc8c ("[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU") Reported-and-tested-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: linux-mm@kvack.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Streetman <ddstreet@ieee.org> Link: http://lkml.kernel.org/r/20161207135438.4310-1-mhocko@kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		2016-12-08 10:08:41 +01:00
..
bpf	bpf: fix states equal logic for varlen access	2016-11-30 14:50:52 -05:00
configs	config: android: enable CONFIG_SECCOMP	2016-10-11 15:06:32 -07:00
debug
events	perf/core: Fix address filter parser	2016-11-21 11:28:36 +01:00
gcov	gcov: add support for gcc version >= 6	2016-07-15 14:54:27 +09:00
irq	genirq: Use irq type from irqdata instead of irqdesc	2016-11-08 15:15:19 +01:00
livepatch	livepatch/module: make TAINT_LIVEPATCH module-specific	2016-08-26 14:42:08 +02:00
locking	lockdep: Limit static allocations if PROVE_LOCKING_SMALL is defined	2016-11-18 11:33:19 -08:00
power	PM / sleep: fix device reference leak in test_suspend	2016-11-02 05:10:04 +01:00
printk	Revert "printk: make reading the kernel log flush pending lines"	2016-11-14 09:31:52 -08:00
rcu	This adds a new gcc plugin named "latent_entropy". It is designed to	2016-10-15 10:03:15 -07:00
sched	sched/autogroup: Do not use autogroup->tg in zombie threads	2016-11-22 12:33:43 +01:00
time	timers: Prevent base clock corruption when forwarding	2016-10-25 16:32:50 +02:00
trace	ftrace: Add more checks for FTRACE_FL_DISABLED in processing ip records	2016-11-14 16:31:49 -05:00
.gitignore
acct.c
async.c
audit_fsnotify.c
audit_tree.c
audit_watch.c	Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit	2016-09-01 15:55:56 -07:00
audit.c	Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit	2016-10-04 14:21:41 -07:00
audit.h	Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit	2016-07-29 17:54:17 -07:00
auditfilter.c	audit: add fields to exclude filter by reusing user filter	2016-06-27 11:01:00 -04:00
auditsc.c	Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit	2016-10-04 14:21:41 -07:00
backtracetest.c
bounds.c
capability.c	kernel: Add noaudit variant of ns_capable()	2016-06-06 20:16:18 +10:00
cgroup_freezer.c
cgroup_pids.c	cgroup: Use lld instead of ld when printing pids controller events_limit	2016-06-21 15:03:36 -04:00
cgroup.c	Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2016-10-14 12:18:50 -07:00
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c	hotplug: Make register and unregister notifier API symmetric	2016-12-08 10:08:41 +01:00
cpuset.c	Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2016-10-14 12:18:50 -07:00
crash_dump.c
cred.c	cred: Reject inodes with invalid ids in set_create_file_as()	2016-06-30 18:05:09 -05:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	sched/autogroup: Do not use autogroup->tg in zombie threads	2016-11-22 12:33:43 +01:00
extable.c
fork.c	fork: Add task stack refcounting sanity check and prevent premature task stack freeing	2016-11-01 07:39:17 +01:00
freezer.c	freezer, oom: check TIF_MEMDIE on the correct task	2016-07-28 16:07:41 -07:00
futex_compat.c
futex.c	futex: Add some more function commentry	2016-09-05 17:20:18 +02:00
groups.c	cred: simpler, 1D supplementary groups	2016-10-07 18:46:30 -07:00
hung_task.c	hung_task: allow hung_task_panic when hung_task_warnings is 0	2016-10-11 15:06:33 -07:00
irq_work.c
jump_label.c	powerpc updates for 4.8 #2	2016-08-05 09:00:54 -04:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c	kcov: properly check if we are in an interrupt	2016-10-27 18:43:42 -07:00
kexec_core.c	kexec: add restriction on kexec_load() segment sizes	2016-08-02 19:35:31 -04:00
kexec_file.c	kexec: fix double-free when failing to relocate the purgatory	2016-09-01 17:52:01 -07:00
kexec_internal.h
kexec.c	kexec: allow architectures to override boot mapping	2016-08-02 19:35:27 -04:00
kmod.c
kprobes.c	kprobes: include <asm/sections.h> instead of <asm-generic/sections.h>	2016-10-11 15:06:31 -07:00
ksysfs.c	kexec: add a kexec_crash_loaded() function	2016-08-02 19:35:30 -04:00
kthread.c	kthread: better support freezable kthread workers	2016-10-11 15:06:33 -07:00
latencytop.c
Makefile	userns: Add per user namespace sysctls.	2016-08-08 13:18:58 -05:00
membarrier.c
memremap.c	mm: fix cache mode of dax pmd mappings	2016-09-09 17:34:46 -07:00
module_signing.c	KEYS: Move the point of trust determination to __key_link()	2016-04-11 22:43:43 +01:00
module-internal.h
module.c	Re-enable CONFIG_MODVERSIONS in a slightly weaker form	2016-11-29 16:01:30 -08:00
notifier.c
nsproxy.c
padata.c	padata: Convert to hotplug state machine	2016-09-19 21:44:30 +02:00
panic.c	x86/panic: replace smp_send_stop() with kdump friendly version in panic path	2016-10-11 15:06:32 -07:00
params.c
pid_namespace.c	Merge branch 'nsfs-ioctls' into HEAD	2016-09-22 20:00:36 -05:00
pid.c	remove lots of IS_ERR_VALUE abuses	2016-05-27 15:26:11 -07:00
profile.c	profile: Convert to hotplug state machine	2016-07-15 10:41:42 +02:00
ptrace.c	mm: replace access_process_vm() write parameter with gup_flags	2016-10-19 08:31:25 -07:00
range.c
reboot.c
relay.c	relay: Use irq_work instead of plain timer for deferred wakeup	2016-10-11 15:06:32 -07:00
resource.c	/proc/iomem: only expose physical resource addresses to privileged users	2016-04-14 12:56:09 -07:00
seccomp.c	seccomp: Fix tracer exit notifications during fatal signals	2016-08-30 16:12:46 -07:00
signal.c	x86/signal: Add SA_{X32,IA32}_ABI sa_flags	2016-09-14 21:28:11 +02:00
smp.c	smp: Allocate smp_call_on_cpu() workqueue on stack too	2016-09-22 14:49:10 +02:00
smpboot.c	kthread/smpboot: do not park in kthread_create_on_cpu()	2016-10-11 15:06:33 -07:00
smpboot.h
softirq.c	softirq: Display IRQ_POLL for irq-poll statistics	2016-10-21 15:45:47 -06:00
stacktrace.c
stop_machine.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-10-03 13:39:00 -07:00
sys_ni.c	x86/pkeys: Fix pkeys build breakage for some non-x86 arches	2016-09-13 14:41:36 +02:00
sys.c	prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable	2016-05-23 17:04:14 -07:00
sysctl_binary.c	kernel/sysctl_binary.c: use generic UUID library	2016-05-20 17:58:30 -07:00
sysctl.c	Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-10-10 13:04:49 -07:00
task_work.c	task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works	2016-08-02 19:35:02 -04:00
taskstats.c	taskstats: fix the length of cgroupstats_cmd_get_policy	2016-11-03 16:55:58 -04:00
test_kprobes.c
torture.c	torture: Convert torture_shutdown() to hrtimer	2016-08-22 10:01:49 -07:00
tracepoint.c
tsacct.c
ucount.c	mntns: Add a limit on the number of mount namespaces.	2016-08-31 07:28:35 -05:00
uid16.c	cred: simpler, 1D supplementary groups	2016-10-07 18:46:30 -07:00
up.c	smp: Add function to execute a function synchronously on a CPU	2016-09-05 13:52:39 +02:00
user_namespace.c	Merge branch 'nsfs-ioctls' into HEAD	2016-09-22 20:00:36 -05:00
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c	Merge branch 'nsfs-ioctls' into HEAD	2016-09-22 20:00:36 -05:00
watchdog.c	Revert "perf/x86/intel, watchdog: Switch NMI watchdog to ref cycles on x86"	2016-07-10 20:58:36 +02:00
workqueue_internal.h
workqueue.c	kthread: rename probe_kthread_data() to kthread_probe_data()	2016-10-11 15:06:33 -07:00