4.4-stable patches

added patches:
	sched-sysctl-check-user-input-value-of-sysctl_sched_time_avg.patch

diff --git a/queue-4.4/sched-sysctl-check-user-input-value-of-sysctl_sched_time_avg.patch b/queue-4.4/sched-sysctl-check-user-input-value-of-sysctl_sched_time_avg.patch
new file mode 100644 (file)
index 0000000..77c81c2
--- /dev/null
+++ b/queue-4.4/sched-sysctl-check-user-input-value-of-sysctl_sched_time_avg.patch
@@ -0,0 +1,85 @@
+From 5ccba44ba118a5000cccc50076b0344632459779 Mon Sep 17 00:00:00 2001
+From: Ethan Zhao <ethan.zhao@oracle.com>
+Date: Mon, 4 Sep 2017 13:59:34 +0800
+Subject: sched/sysctl: Check user input value of sysctl_sched_time_avg
+
+From: Ethan Zhao <ethan.zhao@oracle.com>
+
+commit 5ccba44ba118a5000cccc50076b0344632459779 upstream.
+
+System will hang if user set sysctl_sched_time_avg to 0:
+
+  [root@XXX ~]# sysctl kernel.sched_time_avg_ms=0
+
+  Stack traceback for pid 0
+  0xffff883f6406c600 0 0 1 3 R 0xffff883f6406cf50 *swapper/3
+  ffff883f7ccc3ae8 0000000000000018 ffffffff810c4dd0 0000000000000000
+  0000000000017800 ffff883f7ccc3d78 0000000000000003 ffff883f7ccc3bf8
+  ffffffff810c4fc9 ffff883f7ccc3c08 00000000810c5043 ffff883f7ccc3c08
+  Call Trace:
+  <IRQ> [<ffffffff810c4dd0>] ? update_group_capacity+0x110/0x200
+  [<ffffffff810c4fc9>] ? update_sd_lb_stats+0x109/0x600
+  [<ffffffff810c5507>] ? find_busiest_group+0x47/0x530
+  [<ffffffff810c5b84>] ? load_balance+0x194/0x900
+  [<ffffffff810ad5ca>] ? update_rq_clock.part.83+0x1a/0xe0
+  [<ffffffff810c6d42>] ? rebalance_domains+0x152/0x290
+  [<ffffffff810c6f5c>] ? run_rebalance_domains+0xdc/0x1d0
+  [<ffffffff8108a75b>] ? __do_softirq+0xfb/0x320
+  [<ffffffff8108ac85>] ? irq_exit+0x125/0x130
+  [<ffffffff810b3a17>] ? scheduler_ipi+0x97/0x160
+  [<ffffffff81052709>] ? smp_reschedule_interrupt+0x29/0x30
+  [<ffffffff8173a1be>] ? reschedule_interrupt+0x6e/0x80
+   <EOI> [<ffffffff815bc83c>] ? cpuidle_enter_state+0xcc/0x230
+  [<ffffffff815bc80c>] ? cpuidle_enter_state+0x9c/0x230
+  [<ffffffff815bc9d7>] ? cpuidle_enter+0x17/0x20
+  [<ffffffff810cd6dc>] ? cpu_startup_entry+0x38c/0x420
+  [<ffffffff81053373>] ? start_secondary+0x173/0x1e0
+
+Because divide-by-zero error happens in function:
+
+update_group_capacity()
+  update_cpu_capacity()
+    scale_rt_capacity()
+     {
+          ...
+          total = sched_avg_period() + delta;
+          used = div_u64(avg, total);
+          ...
+     }
+
+To fix this issue, check user input value of sysctl_sched_time_avg, keep
+it unchanged when hitting invalid input, and set the minimum limit of
+sysctl_sched_time_avg to 1 ms.
+
+Reported-by: James Puthukattukaran <james.puthukattukaran@oracle.com>
+Signed-off-by: Ethan Zhao <ethan.zhao@oracle.com>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Cc: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Thomas Gleixner <tglx@linutronix.de>
+Cc: efault@gmx.de
+Cc: ethan.kernel@gmail.com
+Cc: keescook@chromium.org
+Cc: mcgrof@kernel.org
+Cc: <stable@vger.kernel.org>
+Link: http://lkml.kernel.org/r/1504504774-18253-1-git-send-email-ethan.zhao@oracle.com
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Cc: Steve Muckle <smuckle@google.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ kernel/sysctl.c |    3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/kernel/sysctl.c
++++ b/kernel/sysctl.c
+@@ -342,7 +342,8 @@ static struct ctl_table kern_table[] = {
+               .data           = &sysctl_sched_time_avg,
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+-              .proc_handler   = proc_dointvec,
++              .proc_handler   = proc_dointvec_minmax,
++              .extra1         = &one,
+       },
+       {
+               .procname       = "sched_shares_window_ns",