lkml.org 
[lkml]   [2019]   [Feb]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.20 285/352] kernel/hung_task.c: force console verbose before panic
    Date
    4.20-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    [ 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 444b8b5dd69f..4a9191617076 100644
    --- a/kernel/hung_task.c
    +++ b/kernel/hung_task.c
    @@ -112,8 +112,11 @@ 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,
    @@ -135,11 +138,6 @@ 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


    \
     
     \ /
      Last update: 2019-02-11 16:56    [W:4.029 / U:0.064 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site