| From e0a3afc4cf6aa5704b12dfc7da9f4a7f0b6f6f88 Mon Sep 17 00:00:00 2001 |
| From: "Liu, Chuansheng" <chuansheng.liu@intel.com> |
| Date: Thu, 3 Jan 2019 15:26:27 -0800 |
| Subject: kernel/hung_task.c: force console verbose before panic |
| |
| [ Upstream commit 168e06f7937d96c7222037d8a05565e8a6eb00fe ] |
| |
| Based on commit 401c636a0eeb ("kernel/hung_task.c: show all hung tasks |
| before panic"), we could get the call stack of hung task. |
| |
| However, if the console loglevel is not high, we still can not see the |
| useful panic information in practice, and in most cases users don't set |
| console loglevel to high level. |
| |
| This patch is to force console verbose before system panic, so that the |
| real useful information can be seen in the console, instead of being |
| like the following, which doesn't have hung task information. |
| |
| INFO: task init:1 blocked for more than 120 seconds. |
| Tainted: G U W 4.19.0-quilt-2e5dc0ac-g51b6c21d76cc #1 |
| "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. |
| Kernel panic - not syncing: hung_task: blocked tasks |
| CPU: 2 PID: 479 Comm: khungtaskd Tainted: G U W 4.19.0-quilt-2e5dc0ac-g51b6c21d76cc #1 |
| Call Trace: |
| dump_stack+0x4f/0x65 |
| panic+0xde/0x231 |
| watchdog+0x290/0x410 |
| kthread+0x12c/0x150 |
| ret_from_fork+0x35/0x40 |
| reboot: panic mode set: p,w |
| Kernel Offset: 0x34000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) |
| |
| Link: http://lkml.kernel.org/r/27240C0AC20F114CBF8149A2696CBE4A6015B675@SHSMSX101.ccr.corp.intel.com |
| Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> |
| Reviewed-by: Petr Mladek <pmladek@suse.com> |
| Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> |
| Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| kernel/hung_task.c | 12 +++++------- |
| 1 file changed, 5 insertions(+), 7 deletions(-) |
| |
| diff --git a/kernel/hung_task.c b/kernel/hung_task.c |
| index 0cec1241e26f..f9aaf4994062 100644 |
| --- a/kernel/hung_task.c |
| +++ b/kernel/hung_task.c |
| @@ -103,8 +103,11 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) |
| |
| trace_sched_process_hang(t); |
| |
| - if (!sysctl_hung_task_warnings && !sysctl_hung_task_panic) |
| - return; |
| + if (sysctl_hung_task_panic) { |
| + console_verbose(); |
| + hung_task_show_lock = true; |
| + hung_task_call_panic = true; |
| + } |
| |
| /* |
| * Ok, the task did not get scheduled for more than 2 minutes, |
| @@ -126,11 +129,6 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) |
| } |
| |
| touch_nmi_watchdog(); |
| - |
| - if (sysctl_hung_task_panic) { |
| - hung_task_show_lock = true; |
| - hung_task_call_panic = true; |
| - } |
| } |
| |
| /* |
| -- |
| 2.19.1 |
| |
