linux-kernel - [lkp] [rcu] a7410f28ce: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 0-... } 25089 jiffies s: 9 root: 0x1/.

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Date:   Wed, 9 Nov 2016 14:25:39 +0800
From:   kernel test robot <xiaolong.ye@...el.com>
To:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:     "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>, lkp@...org
Subject: [lkp] [rcu]  a7410f28ce: INFO: rcu_sched detected expedited stalls
 on CPUs/tasks: { 0-... } 25089 jiffies s: 9 root: 0x1/.


FYI, we noticed the following commit:

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
commit a7410f28ceb566bda840b4afc278747c63383fb6 ("rcu: update: Make RCU_EXPEDITE_BOOT be the default")

in testcase: boot

on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 1G

caused below changes:


+-----------------------------------------------------------------------------------+------------+------------+
|                                                                                   | 9aa96e24ec | a7410f28ce |
+-----------------------------------------------------------------------------------+------------+------------+
| boot_successes                                                                    | 3          | 7          |
| boot_failures                                                                     | 17         | 17         |
| INFO:rcu_sched_self-detected_stall_on_CPU                                         | 17         | 14         |
| calltrace:mark_rodata_ro                                                          | 17         | 14         |
| INFO:rcu_sched_detected_stalls_on_CPUs/tasks                                      | 15         | 14         |
| INFO:rcu_sched_detected_expedited_stalls_on_CPUs/tasks:{#-...}#jiffies_s:#root:#/ | 0          | 15         |
+-----------------------------------------------------------------------------------+------------+------------+



[   38.504100] Write protecting the kernel read-only data: 47104k
[   38.511102] Freeing unused kernel memory: 720K (ffff88000314c000 - ffff880003200000)
[   38.547480] Freeing unused kernel memory: 1032K (ffff880003cfe000 - ffff880003e00000)
[  149.710631] INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 0-... } 25089 jiffies s: 9 root: 0x1/.
[  149.720353] blocking rcu_node structures:
[  149.722359] Task dump for CPU 0:
[  149.724094] swapper/0       R  running task        0     1      0 0x00000008
[  149.726939]  ffff88002ccc98c0 ffff88002d8202c0 ffff88002cccc9c0 ffffffff83f30e40
[  149.730972]  ffff88002ccc9b30 ffff88002ccd7c80 ffffffff8313afd3 ffffffff83c43f92
[  149.735011]  ffffffff81e50101 1ffff1000599af77 0000000000000000 0000000041b58ab3
[  149.739029] Call Trace:
[  149.740574]  [<ffffffff8313afd3>] ? __schedule+0xad3/0xb02
[  149.742801]  [<ffffffff81e50101>] ? hide_cursor+0x175/0x20d
[  149.745015]  [<ffffffff8313a500>] ? cb_alloc+0x264/0x264


To reproduce:

        git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email



Thanks,
Xiaolong

View attachment "config-4.9.0-rc1-00026-ga7410f2" of type "text/plain" (90595 bytes)

View attachment "job-script" of type "text/plain" (4000 bytes)

Download attachment "dmesg.xz" of type "application/octet-stream" (84412 bytes)