From: Ye Xiaolong <xiaolong.ye@intel.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Petr Mladek <pmladek@suse.com>, Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Eric Biederman <ebiederm@xmission.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>, Pavel Machek <pavel@ucw.cz>,
Len Brown <len.brown@intel.com>,
linux-kernel@vger.kernel.org, lkp@01.org
Subject: Re: [printk] fbc14616f4: BUG:kernel_reboot-without-warning_in_test_stage
Date: Fri, 31 Mar 2017 14:39:13 +0800 [thread overview]
Message-ID: <20170331063913.GE20961@yexl-desktop> (raw)
In-Reply-To: <20170331040438.GA366@jagdpanzerIV.localdomain>
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.
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
>
next prev parent reply other threads:[~2017-03-31 6:40 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 9:25 [RFC][PATCHv2 0/8] printk: introduce printing kernel thread Sergey Senozhatsky
2017-03-29 9:25 ` [RFC][PATCHv2 1/8] printk: move printk_pending out of per-cpu Sergey Senozhatsky
2017-03-31 13:09 ` Petr Mladek
2017-03-31 13:33 ` Peter Zijlstra
2017-04-03 11:23 ` Sergey Senozhatsky
2017-04-03 12:43 ` Petr Mladek
2017-03-29 9:25 ` [RFC][PATCHv2 2/8] printk: introduce printing kernel thread Sergey Senozhatsky
2017-04-04 9:01 ` Petr Mladek
2017-04-04 9:36 ` Sergey Senozhatsky
2017-04-06 17:14 ` Pavel Machek
2017-04-07 5:12 ` Sergey Senozhatsky
2017-04-07 7:21 ` Pavel Machek
2017-04-07 8:15 ` Sergey Senozhatsky
2017-04-07 12:06 ` Pavel Machek
2017-03-29 9:25 ` [RFC][PATCHv2 3/8] printk: offload printing from wake_up_klogd_work_func() Sergey Senozhatsky
2017-03-31 14:56 ` Petr Mladek
2017-04-04 16:15 ` Sergey Senozhatsky
2017-03-29 9:25 ` [RFC][PATCHv2 4/8] pm: switch to printk.emergency mode in unsafe places Sergey Senozhatsky
2017-03-31 15:06 ` Petr Mladek
2017-04-06 17:20 ` Pavel Machek
2017-04-09 10:59 ` Andreas Mohr
2017-04-10 12:20 ` Petr Mladek
2017-04-10 14:38 ` Sergey Senozhatsky
2017-03-29 9:25 ` [RFC][PATCHv2 5/8] sysrq: " Sergey Senozhatsky
2017-03-31 15:37 ` Petr Mladek
2017-04-01 0:04 ` Sergey Senozhatsky
2017-03-29 9:25 ` [RFC][PATCHv2 6/8] kexec: " Sergey Senozhatsky
2017-03-31 15:39 ` Petr Mladek
2017-03-29 9:25 ` [RFC][PATCHv2 7/8] printk: add printk emergency_mode parameter Sergey Senozhatsky
2017-04-03 15:29 ` Petr Mladek
2017-04-04 8:29 ` Sergey Senozhatsky
2017-03-29 9:25 ` [RFC][PATCHv2 8/8] printk: enable printk offloading Sergey Senozhatsky
2017-03-30 21:38 ` [printk] fbc14616f4: BUG:kernel_reboot-without-warning_in_test_stage kernel test robot
2017-03-31 2:35 ` Sergey Senozhatsky
2017-03-31 4:04 ` Sergey Senozhatsky
2017-03-31 6:39 ` Ye Xiaolong [this message]
2017-03-31 14:47 ` Sergey Senozhatsky
2017-03-31 15:28 ` Eric W. Biederman
2017-04-03 9:31 ` Jan Kara
2017-04-03 10:06 ` Petr Mladek
2017-04-06 17:33 ` Pavel Machek
2017-04-07 4:44 ` Sergey Senozhatsky
2017-04-07 7:15 ` Pavel Machek
2017-04-07 7:46 ` Sergey Senozhatsky
2017-04-07 8:14 ` Pavel Machek
2017-04-07 12:10 ` Sergey Senozhatsky
2017-04-07 12:44 ` Pavel Machek
2017-04-07 14:40 ` Steven Rostedt
2017-05-08 6:37 ` Sergey Senozhatsky
2017-05-17 13:13 ` Petr Mladek
2017-04-07 15:13 ` Sergey Senozhatsky
2017-04-07 15:23 ` Peter Zijlstra
2017-04-07 15:40 ` Sergey Senozhatsky
2017-04-09 18:21 ` Eric W. Biederman
2017-04-10 4:46 ` Sergey Senozhatsky
2017-04-09 10:12 ` Pavel Machek
2017-04-10 4:53 ` Sergey Senozhatsky
2017-04-10 11:54 ` Petr Mladek
2017-04-10 15:08 ` Sergey Senozhatsky
2017-04-10 18:48 ` Pavel Machek
2017-04-11 1:46 ` Sergey Senozhatsky
2017-04-11 16:19 ` Sergey Senozhatsky
2017-04-12 18:43 ` Pavel Machek
2017-04-13 4:34 ` Sergey Senozhatsky
2017-04-13 5:50 ` Sergey Senozhatsky
2017-04-13 8:19 ` Sergey Senozhatsky
2017-04-13 14:03 ` Petr Mladek
2017-04-14 4:42 ` Sergey Senozhatsky
2017-04-07 14:29 ` Steven Rostedt
2017-04-09 9:57 ` Pavel Machek
2017-04-03 10:51 ` Sergey Senozhatsky
2017-04-05 7:29 ` Ye Xiaolong
2017-04-05 8:40 ` Sergey Senozhatsky
2017-04-03 15:42 ` [RFC][PATCHv2 8/8] printk: enable printk offloading Petr Mladek
2017-04-04 13:20 ` Sergey Senozhatsky
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