Ethan Zhao
21a24b5db1
sched/sysctl: Check user input value of sysctl_sched_time_avg
commit 5ccba44ba1 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>
2018-09-05 09:18:33 +02:00
..
2018-08-06 16:24:37 +02:00
2018-05-30 07:49:17 +02:00
2018-05-30 07:49:12 +02:00
2018-01-23 19:50:10 +01:00
2018-08-09 12:19:27 +02:00
2018-08-24 13:26:55 +02:00
2018-07-17 11:31:46 +02:00
2018-03-22 09:23:23 +01:00
2017-10-18 09:20:41 +02:00
2018-05-30 07:49:08 +02:00
2018-08-09 12:19:27 +02:00
2018-08-24 13:26:58 +02:00
2018-01-10 09:27:08 +01:00
2018-02-16 20:09:45 +01:00
2017-08-24 17:02:35 -07:00
2018-05-30 07:49:16 +02:00
2018-08-06 16:24:38 +02:00
2018-08-06 16:24:38 +02:00
2017-04-21 09:30:04 +02:00
2017-10-12 11:27:35 +02:00
2018-05-26 08:48:51 +02:00
2017-07-21 07:44:56 +02:00
2018-01-05 15:44:23 +01:00
2018-05-26 08:48:51 +02:00
2018-01-10 09:27:10 +01:00
2017-12-16 10:33:55 +01:00
2018-04-08 11:51:56 +02:00
2017-04-21 09:30:04 +02:00
2017-03-12 06:37:26 +01:00
2018-02-25 11:03:52 +01:00
2017-05-20 14:27:02 +02:00
2017-07-05 14:37:19 +02:00
2017-05-25 14:30:11 +02:00
2018-04-13 19:50:03 +02:00
2018-02-25 11:03:44 +01:00
2017-06-14 13:16:20 +02:00
2018-05-30 07:49:00 +02:00
2018-04-24 09:32:05 +02:00
2018-07-25 10:18:27 +02:00
2018-05-30 07:48:52 +02:00
2018-07-25 10:18:26 +02:00
2018-09-05 09:18:33 +02:00
2018-05-16 10:06:47 +02:00
2018-01-10 09:27:10 +01:00
2017-11-15 17:13:11 +01:00
2018-05-30 07:49:04 +02:00