lkml.org 
[lkml]   [2017]   [Apr]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [printk] fbc14616f4: BUG:kernel_reboot-without-warning_in_test_stage
On 03/31, Ye Xiaolong wrote:
>On 03/31, Sergey Senozhatsky wrote:
>>On (03/31/17 11:35), Sergey Senozhatsky wrote:
>>[..]
>>> > [ 21.009531] VFS: Warning: trinity-c2 using old stat() call. Recompile your binary.
>>> > [ 21.148898] VFS: Warning: trinity-c0 using old stat() call. Recompile your binary.
>>> > [ 22.298208] warning: process `trinity-c2' used the deprecated sysctl system call with
>>> >
>>> > Elapsed time: 310
>>> > BUG: kernel reboot-without-warning in test stage
>>>
>>> so as far as I understand, this is the "missing kernel messages"
>>> type of bug report. a worst case scenario.
>>
>>panic() should have called console_flush_on_panic(), which sould have
>>flushed the messages regardless the printk_kthread state. so it probably
>>was not panic() that rebooted the kernel. (probably).
>>
>>kernel_restart() and kernel_halt() have pr_emerg() messages, printk switches
>>to printk_emergency mode the first time it sees EMERG level message. (may be
>>we switch to late).
>>
>>on the other hand, there is a emergency_restart(), where we don't switch
>>to printk_emergency mode and don't flush the existing kernel messages.
>>there is a bunch of places that call emergency_restart(), including sysrq.
>>
>>may I ask you, how do you usually restart the vm after the test?
>>`echo X > /proc/sysrq-trigger'?
>
>Yes.
>
>>
>>does this patch make it any better?
>
>I am trying it and will post the result once I get it.

Sorry for the late. I applied the patch of on top of the fbc14616f4 ("printk: enable printk offloading")
and the "reboot-without-waring" issue is gone for 6 times of tests.

testcase/path_params/tbox_group/run: trinity/300s/vm-kbuild-yocto-ia32

fbc14616f483788a a75384abd8885080d6923d7036
---------------- --------------------------
4:4 -100% 0:6 dmesg.BUG:kernel_reboot-without-warning_in_test_stage

Thanks,
Xiaolong

>
>Thanks,
>Xiaolong
>>
>>---
>> drivers/tty/sysrq.c | 8 ++------
>> 1 file changed, 2 insertions(+), 6 deletions(-)
>>
>>diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
>>index 817dfb69914d..069f5540be36 100644
>>--- a/drivers/tty/sysrq.c
>>+++ b/drivers/tty/sysrq.c
>>@@ -240,7 +240,6 @@ static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);
>>
>> static void sysrq_handle_showallcpus(int key)
>> {
>>- printk_emergency_begin();
>> /*
>> * Fall back to the workqueue based printing if the
>> * backtrace printing did not succeed or the
>>@@ -255,7 +254,6 @@ static void sysrq_handle_showallcpus(int key)
>> }
>> schedule_work(&sysrq_showallcpus);
>> }
>>- printk_emergency_end();
>> }
>>
>> static struct sysrq_key_op sysrq_showallcpus_op = {
>>@@ -282,10 +280,8 @@ static struct sysrq_key_op sysrq_showregs_op = {
>>
>> static void sysrq_handle_showstate(int key)
>> {
>>- printk_emergency_begin();
>> show_state();
>> show_workqueue_state();
>>- printk_emergency_end();
>> }
>> static struct sysrq_key_op sysrq_showstate_op = {
>> .handler = sysrq_handle_showstate,
>>@@ -296,9 +292,7 @@ static struct sysrq_key_op sysrq_showstate_op = {
>>
>> static void sysrq_handle_showstate_blocked(int key)
>> {
>>- printk_emergency_begin();
>> show_state_filter(TASK_UNINTERRUPTIBLE);
>>- printk_emergency_end();
>> }
>> static struct sysrq_key_op sysrq_showstate_blocked_op = {
>> .handler = sysrq_handle_showstate_blocked,
>>@@ -537,6 +531,7 @@ void __handle_sysrq(int key, bool check_mask)
>> int orig_log_level;
>> int i;
>>
>>+ printk_emergency_begin();
>> rcu_sysrq_start();
>> rcu_read_lock();
>> /*
>>@@ -582,6 +577,7 @@ void __handle_sysrq(int key, bool check_mask)
>> }
>> rcu_read_unlock();
>> rcu_sysrq_end();
>>+ printk_emergency_end();
>> }
>>
>> void handle_sysrq(int key)
>>--
>>2.12.2
>>

\
 
 \ /
  Last update: 2017-04-05 09:31    [W:0.143 / U:0.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site