Re: [Question] A panic when reboot --force the system

From: Xishi Qiu
Date: Mon Oct 26 2015 - 04:57:20 EST


On 2015/10/23 17:45, Rui Xiang wrote:

> Hiïlist
>
> I encounter a panic about init process.
>
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000007
>
> Pid: 1, comm: init Tainted: G R O 3.4.24.19-0.11-default #1
> Call Trace:
> [<ffffffff8144dd24>] panic+0xc1/0x1e2
> [<ffffffff8104483b>] do_exit+0x7db/0x8d0
> [<ffffffff81044c7a>] do_group_exit+0x3a/0xa0
> [<ffffffff8105394b>] get_signal_to_deliver+0x1ab/0x5e0
> [<ffffffff81002270>] do_signal+0x60/0x5f0
> [<ffffffff8145bf97>] ? do_page_fault+0x4a7/0x4d0
> [<ffffffff81170d2c>] ? poll_select_copy_remaining+0xec/0x140
> [<ffffffff81002885>] do_notify_resume+0x65/0x80
> [<ffffffff8124ca7e>] ? trace_hardirqs_on_thunk+0x3a/0x3c
> [<ffffffff814587ab>] retint_signal+0x4d/0x92
>
> The system has a little memory left, then reboot it, and get the panic.
>
> In our host, kswapd would be wake up while using a lot of memory, and then reclaim
> some pages from init process. If we execute *"reboot"* or *"reboot -f"* to reboot
> host through sysvinit, reboot process will call sys_reboot and shut down the sas
> driver(disk), then will trigger the panic of init process.
>
> As follow,
>
> HOST reboot process init process
> use a lot of memory
> wake up kswapd
> reclaim some pages
> (these pages are code segment
> or data segment of init process)
> from init thread (pid=1)
> reboot
> sys_reboot
> shutdown disk driver
>


init thread read data from disk

Hi,

Does anyone know will init thread read data from disk after shutdown
the disk driver?

Thanks,
Xishi Qiu

> page_fault
> filemap_fault
> readpage failed because the disk is closed
> return VM_FAULT_SIGBUS
> send signal SIGBUS
> do_signal
> do_exit
> trigger the panic
>
>
> It seems that reboot or force reboot through *sysvinit* have the problem.
> Furthermore, using reboot -f in *systemd* should also have this problem, right?
>
> And is that a bug for current reboot process in sysvinit or systemd?
>
> All comments are welcome, thanks.
>
> .
>


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