The patch titled
Subject: kernel/hung_task.c: force console verbose before panic
has been added to the -mm tree. Its filename is
kernel-hung_taskc-force-console-verbose-before-panic.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kernel-hung_taskc-force-console-verbose-before-panic.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kernel-hung_taskc-force-console-verbose-before-panic.patch
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------------------------------------------------------
From: "Liu, Chuansheng" <chuansheng.liu@xxxxxxxxx>
Subject: kernel/hung_task.c: force console verbose before panic
Based on 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.
[ 246.916600] INFO: task init:1 blocked for more than 120 seconds.
[ 246.922320] Tainted: G U W 4.19.0-quilt-2e5dc0ac-g51b6c21d76cc #1
[ 246.926790] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 246.932553] Kernel panic - not syncing: hung_task: blocked tasks
[ 246.938503] CPU: 2 PID: 479 Comm: khungtaskd Tainted: G U W 4.19.0-quilt-2e5dc0ac-g51b6c21d76cc #1
[ 246.990266] Call Trace:
[ 246.991707] dump_stack+0x4f/0x65
[ 246.993710] panic+0xde/0x231
[ 246.995445] watchdog+0x290/0x410
[ 246.997390] kthread+0x12c/0x150
[ 246.999301] ? reset_hung_task_detector+0x20/0x20
[ 247.004825] ? kthread_create_worker_on_cpu+0x70/0x70
[ 247.007735] ret_from_fork+0x35/0x40
[ 247.010280] reboot: panic mode set: p,w
[ 247.012619] Kernel Offset: 0x34000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
Link: http://lkml.kernel.org/r/27240C0AC20F114CBF8149A2696CBE4A6015B675@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Chuansheng Liu <chuansheng.liu@xxxxxxxxx>
Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/kernel/hung_task.c~kernel-hung_taskc-force-console-verbose-before-panic
+++ a/kernel/hung_task.c
@@ -112,8 +112,11 @@ static void check_hung_task(struct task_
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,
@@ -135,11 +138,6 @@ static void check_hung_task(struct task_
}
touch_nmi_watchdog();
-
- if (sysctl_hung_task_panic) {
- hung_task_show_lock = true;
- hung_task_call_panic = true;
- }
}
/*
_
Patches currently in -mm which might be from chuansheng.liu@xxxxxxxxx are
kernel-hung_taskc-force-console-verbose-before-panic.patch
