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Kirill Tkhai 6419265899 sched/fair: Fix division by zero sysctl_numa_balancing_scan_size 
File /proc/sys/kernel/numa_balancing_scan_size_mb allows writing of zero.

This bash command reproduces problem:

$ while :; do echo 0 > /proc/sys/kernel/numa_balancing_scan_size_mb; \
	   echo 256 > /proc/sys/kernel/numa_balancing_scan_size_mb; done

	divide error: 0000 [#1] SMP
	Modules linked in:
	CPU: 0 PID: 24112 Comm: bash Not tainted 3.17.0+ #8
	Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
	task: ffff88013c852600 ti: ffff880037a68000 task.ti: ffff880037a68000
	RIP: 0010:[<ffffffff81074191>]  [<ffffffff81074191>] task_scan_min+0x21/0x50
	RSP: 0000:ffff880037a6bce0  EFLAGS: 00010246
	RAX: 0000000000000a00 RBX: 00000000000003e8 RCX: 0000000000000000
	RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88013c852600
	RBP: ffff880037a6bcf0 R08: 0000000000000001 R09: 0000000000015c90
	R10: ffff880239bf6c00 R11: 0000000000000016 R12: 0000000000003fff
	R13: ffff88013c852600 R14: ffffea0008d1b000 R15: 0000000000000003
	FS:  00007f12bb048700(0000) GS:ffff88007da00000(0000) knlGS:0000000000000000
	CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
	CR2: 0000000001505678 CR3: 0000000234770000 CR4: 00000000000006f0
	Stack:
	 ffff88013c852600 0000000000003fff ffff880037a6bd18 ffffffff810741d1
	 ffff88013c852600 0000000000003fff 000000000002bfff ffff880037a6bda8
	 ffffffff81077ef7 ffffea0008a56d40 0000000000000001 0000000000000001
	Call Trace:
	 [<ffffffff810741d1>] task_scan_max+0x11/0x40
	 [<ffffffff81077ef7>] task_numa_fault+0x1f7/0xae0
	 [<ffffffff8115a896>] ? migrate_misplaced_page+0x276/0x300
	 [<ffffffff81134a4d>] handle_mm_fault+0x62d/0xba0
	 [<ffffffff8103e2f1>] __do_page_fault+0x191/0x510
	 [<ffffffff81030122>] ? native_smp_send_reschedule+0x42/0x60
	 [<ffffffff8106dc00>] ? check_preempt_curr+0x80/0xa0
	 [<ffffffff8107092c>] ? wake_up_new_task+0x11c/0x1a0
	 [<ffffffff8104887d>] ? do_fork+0x14d/0x340
	 [<ffffffff811799bb>] ? get_unused_fd_flags+0x2b/0x30
	 [<ffffffff811799df>] ? __fd_install+0x1f/0x60
	 [<ffffffff8103e67c>] do_page_fault+0xc/0x10
	 [<ffffffff8150d322>] page_fault+0x22/0x30
	RIP  [<ffffffff81074191>] task_scan_min+0x21/0x50
	RSP <ffff880037a6bce0>
	---[ end trace 9a826d16936c04de ]---

Also fix race in task_scan_min (it depends on compiler behaviour).

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: David Rientjes <rientjes@google.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Link: http://lkml.kernel.org/r/1413455977.24793.78.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-28 10:46:04 +01:00
..
bpf
bpf: add search pruning optimization to verifier
2014-10-01 21:30:33 -04:00
configs
x86: Add "make tinyconfig" to configure the tiniest possible kernel
2014-08-08 16:30:24 -07:00
debug
kdb: replace strnicmp with strncasecmp
2014-10-14 02:18:25 +02:00
events
Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-15 07:48:18 +02:00
gcov
ARM: 8153/1: Enable gcov support on the ARM architecture
2014-09-26 14:39:57 +01:00
irq
Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-15 07:48:18 +02:00
locking
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-10-13 15:51:40 +02:00
power
Merge branch 'freezer'
2014-10-23 23:02:45 +02:00
printk
Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-15 07:48:18 +02:00
rcu
rcu: Eliminate deadlock between CPU hotplug and expedited grace periods
2014-09-18 16:22:27 -07:00
sched
sched/fair: Fix division by zero sysctl_numa_balancing_scan_size
2014-10-28 10:46:04 +01:00
time
Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-15 07:48:18 +02:00
trace
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-10-13 16:23:15 +02:00
.gitignore
Ignore generated file kernel/x509_certificate_list
2013-12-10 18:21:34 +00:00
acct.c
acct: eliminate compile warning
2014-10-09 22:26:04 -04:00
async.c
kernel/async.c: switch to pr_foo()
2014-10-09 22:26:04 -04:00
audit_tree.c
audit: rename audit_log_remove_rule to disambiguate for trees
2014-10-10 15:30:25 -04:00
audit_watch.c
audit: invalid op= values for rules
2014-09-23 16:37:53 -04:00
audit.c
Merge git://git.infradead.org/users/eparis/audit
2014-10-19 16:25:56 -07:00
audit.h
audit: reduce scope of audit_log_fcaps
2014-09-23 16:37:51 -04:00
auditfilter.c
Merge git://git.infradead.org/users/eparis/audit
2014-10-19 16:25:56 -07:00
auditsc.c
Merge git://git.infradead.org/users/eparis/audit
2014-10-19 16:25:56 -07:00
backtracetest.c
kernel/backtracetest.c: replace no level printk by pr_info()
2014-06-04 16:54:14 -07:00
bounds.c
page-cgroup: get rid of NR_PCG_FLAGS
2014-08-08 15:57:18 -07:00
capability.c
CAPABILITIES: remove undefined caps from all processes
2014-07-24 21:53:47 +10:00
cgroup_freezer.c
cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes
2014-07-15 11:05:09 -04:00
cgroup.c
Merge branch 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-10 07:26:02 -04:00
compat.c
compat: nanosleep: Clarify error handling
2014-09-06 12:58:18 +02:00
configs.c
…
context_tracking.c
x86/kprobes: Fix build errors and blacklist context_track_user
2014-06-14 09:07:44 +02:00
cpu_pm.c
…
cpu.c
rcu: Eliminate deadlock between CPU hotplug and expedited grace periods
2014-09-18 16:22:27 -07:00
cpuset.c
Merge branch 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2014-10-10 07:24:40 -04:00
crash_dump.c
crash_dump: Make is_kdump_kernel() accessible from modules
2014-08-25 15:42:19 -07:00
cred.c
…
delayacct.c
delayacct: Remove braindamaged type conversions
2014-07-23 10:18:06 -07:00
dma.c
…
elfcore.c
…
exec_domain.c
kernel/exec_domain.c: code clean-up
2014-06-04 16:54:15 -07:00
exit.c
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-10-13 16:23:15 +02:00
extable.c
asmlinkage: Make main_extable_sort_needed visible
2014-02-13 18:13:22 -08:00
fork.c
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-10-13 16:23:15 +02:00
freezer.c
freezer: remove obsolete comments in __thaw_task()
2014-10-21 23:44:20 +02:00
futex_compat.c
compat: Get rid of (get|put)_compat_time(val|spec)
2014-02-02 14:09:12 -08:00
futex.c
futex: Ensure get_futex_key_refs() always implies a barrier
2014-10-18 09:28:51 -07:00
groups.c
kernel/groups.c: remove return value of set_groups
2014-04-03 16:21:05 -07:00
hung_task.c
kernel/hung_task.c: convert simple_strtoul to kstrtouint
2014-06-04 16:54:15 -07:00
irq_work.c
Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-15 07:48:18 +02:00
jump_label.c
…
kallsyms.c
kernel/kallsyms.c: use __seq_open_private()
2014-10-14 02:18:16 +02:00
kcmp.c
kcmp: fix standard comparison bug
2014-09-10 15:42:12 -07:00
Kconfig.freezer
…
Kconfig.hz
…
Kconfig.locks
locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER
2014-07-16 14:57:13 +02:00
Kconfig.preempt
…
kexec.c
kexec: remove the unused function parameter
2014-10-14 02:18:21 +02:00
kmod.c
signals: change wait_for_helper() to use kernel_sigaction()
2014-06-06 16:08:12 -07:00
kprobes.c
kprobes: Skip kretprobe hit in NMI context to avoid deadlock
2014-08-08 10:38:04 +02:00
ksysfs.c
kobject: Make support for uevent_helper optional.
2014-04-25 12:00:49 -07:00
kthread.c
kernel/kthread.c: partial revert of 81c98869faa5 ("kthread: ensure locality of task_struct allocations")
2014-10-09 22:25:51 -04:00
latencytop.c
kernel/latencytop.c: convert seq_printf to seq_puts
2014-06-04 16:54:15 -07:00
Makefile
bin2c: move bin2c in scripts/basic
2014-08-08 15:57:32 -07:00
module_signing.c
…
module-internal.h
…
module.c
A single panic fix for a rare race, stable CC'd.
2014-10-18 10:24:26 -07:00
notifier.c
kprobes, notifier: Use NOKPROBE_SYMBOL macro in notifier
2014-04-24 10:26:39 +02:00
nsproxy.c
namespaces: Use task_lock and not rcu to protect nsproxy
2014-07-29 18:08:50 -07:00
padata.c
padata: Fix wrong usage of rcu_dereference()
2013-12-05 21:28:42 +08:00
panic.c
panic: add TAINT_SOFTLOCKUP
2014-08-08 15:57:24 -07:00
params.c
kernel/param: consolidate __{start,stop}___param[] in <linux/moduleparam.h>
2014-10-14 02:18:28 +02:00
pid_namespace.c
pid_namespace: pidns_get() should check task_active_pid_ns() != NULL
2014-04-02 16:20:21 -07:00
pid.c
…
profile.c
kernel/profile.c: use static const char instead of static char
2014-06-06 16:08:13 -07:00
ptrace.c
sched: Remove proliferation of wait_on_bit() action functions
2014-07-16 15:10:39 +02:00
range.c
…
reboot.c
kernel: add support for kernel restart handler call chain
2014-09-26 00:00:06 -07:00
relay.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2014-04-12 14:49:50 -07:00
res_counter.c
kernel/res_counter.c: replace simple_strtoull by kstrtoull
2014-06-04 16:54:15 -07:00
resource.c
x86: optimize resource lookups for ioremap
2014-10-14 02:18:22 +02:00
seccomp.c
Merge branch 'x86-seccomp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-10-14 02:27:06 +02:00
signal.c
Merge branch 'signal-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc
2014-08-09 09:58:12 -07:00
smp.c
Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-15 07:48:18 +02:00
smpboot.c
…
smpboot.h
…
softirq.c
Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-15 07:48:18 +02:00
stacktrace.c
…
stop_machine.c
kernel/stop_machine.c: kernel-doc warning fix
2014-06-04 16:54:15 -07:00
sys_ni.c
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2014-10-08 21:40:54 -04:00
sys.c
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-10-13 16:23:15 +02:00
sysctl_binary.c
dmaengine-3.17
2014-10-07 20:39:25 -04:00
sysctl.c
sched/fair: Fix division by zero sysctl_numa_balancing_scan_size
2014-10-28 10:46:04 +01:00
system_certificates.S
KEYS: correct alignment of system_certificate_list content in assembly file
2013-12-10 18:25:28 +00:00
system_keyring.c
KEYS: validate certificate trust only with builtin keys
2014-07-17 09:35:17 -04:00
task_work.c
…
taskstats.c
scheduler: Replace __get_cpu_var with this_cpu_ptr
2014-08-26 13:45:45 -04:00
test_kprobes.c
kernel/test_kprobes.c: use current logging functions
2014-08-08 15:57:18 -07:00
torture.c
torture: Address race in module cleanup
2014-09-16 13:41:06 -07:00
tracepoint.c
tracing: syscall_regfunc() should not skip kernel threads
2014-06-21 00:15:26 -04:00
tsacct.c
sched: Make task->start_time nanoseconds based
2014-07-23 10:18:05 -07:00
uid16.c
…
up.c
smp: Rename __smp_call_function_single() to smp_call_function_single_async()
2014-02-24 14:47:15 -08:00
user_namespace.c
proc: constify seq_operations
2014-08-08 15:57:22 -07:00
user-return-notifier.c
scheduler: Replace __get_cpu_var with this_cpu_ptr
2014-08-26 13:45:45 -04:00
user.c
kernel/user.c: drop unused field 'files' from user_struct
2014-06-04 16:54:16 -07:00
utsname_sysctl.c
sysctl: convert use of typedef ctl_table to struct ctl_table
2014-06-06 16:08:16 -07:00
utsname.c
namespaces: Use task_lock and not rcu to protect nsproxy
2014-07-29 18:08:50 -07:00
watchdog.c
Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2014-10-15 07:48:18 +02:00
workqueue_internal.h
workqueue: rename manager_mutex to attach_mutex
2014-05-20 10:59:32 -04:00
workqueue.c
workqueue: Use cond_resched_rcu_qs macro
2014-10-06 05:58:26 -07:00