linux_dsm_epyc7002/kernel
Srivatsa S. Bhat 075663d198 CPU hotplug, debug: detect imbalance between get_online_cpus() and put_online_cpus()
The synchronization between CPU hotplug readers and writers is achieved
by means of refcounting, safeguarded by the cpu_hotplug.lock.

get_online_cpus() increments the refcount, whereas put_online_cpus()
decrements it.  If we ever hit an imbalance between the two, we end up
compromising the guarantees of the hotplug synchronization i.e, for
example, an extra call to put_online_cpus() can end up allowing a
hotplug reader to execute concurrently with a hotplug writer.

So, add a WARN_ON() in put_online_cpus() to detect such cases where the
refcount can go negative, and also attempt to fix it up, so that we can
continue to run.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:15 +09:00
..
debug
events Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-10-02 20:25:04 -07:00
gcov
irq
power
sched Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-10-01 10:43:39 -07:00
time Power management updates for 3.7-rc1 2012-10-02 18:32:35 -07:00
trace Merge branch 'virtio-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux 2012-10-07 21:04:56 +09:00
.gitignore
acct.c
async.c
audit_tree.c
audit_watch.c
audit.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2012-10-02 13:38:27 -07:00
audit.h
auditfilter.c
auditsc.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2012-10-02 21:38:48 -07:00
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c Merge branch 'for-3.7-hierarchy' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2012-10-02 10:52:28 -07:00
compat.c
configs.c
cpu_pm.c
cpu.c CPU hotplug, debug: detect imbalance between get_online_cpus() and put_online_cpus() 2012-10-09 16:22:15 +09:00
cpuset.c
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-10-02 20:25:04 -07:00
extable.c
fork.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2012-10-02 13:38:27 -07:00
freezer.c
futex_compat.c
futex.c
groups.c
hrtimer.c
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c kdump: remove unneeded include 2012-10-06 03:05:19 +09:00
kfifo.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
lglock.c
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
lockdep.c
Makefile
module.c
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-10-02 11:11:09 -07:00
pid.c
posix-cpu-timers.c
posix-timers.c
printk.c
profile.c
ptrace.c
range.c
rcu.h
rcupdate.c
rcutiny_plugin.h
rcutiny.c
rcutorture.c
rcutree_plugin.h
rcutree_trace.c
rcutree.c
rcutree.h
relay.c
res_counter.c
resource.c kernel/resource.c: fix stack overflow in __reserve_region_with_split() 2012-10-06 03:05:31 +09:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
seccomp.c
semaphore.c
signal.c coredump: pass siginfo_t* to do_coredump() and below, not merely signr 2012-10-06 03:05:16 +09:00
smp.c
smpboot.c
smpboot.h
softirq.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-10-01 10:43:39 -07:00
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c poweroff: fix bug in orderly_poweroff() 2012-10-06 03:04:48 +09:00
sysctl_binary.c
sysctl.c Kconfig: clean up the "#if defined(arch)" list for exception-trace sysctl entry 2012-10-09 16:22:14 +09:00
task_work.c
taskstats.c taskstats: cgroupstats_user_cmd() may leak on error 2012-10-06 03:05:31 +09:00
test_kprobes.c
time.c
timeconst.pl
timer.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-10-01 10:45:16 -07:00
tracepoint.c
tsacct.c
uid16.c
up.c
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
wait.c
watchdog.c
workqueue_sched.h
workqueue.c Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2012-10-02 09:54:49 -07:00