[Devel] [PATCH RH7] fence-watchdog: return back message printing about fencing

[Kirill Tkhai]

On 14.09.2016 13:10, Pavel Tikhomirov wrote:
> Use stock panic for crash and schedule work for reboot:
> 
> We've temporary stopped printing the message about fencing
> as that caused problems in video card driver which needs to
> vmalloc but can not do so in_interrupt() context.(reproduces
> rarely 1/10 when triger fence watchdog from net_rx_action)
> 
> So now we try to use stock panic's print to deliver message
> about fencing in kernel log.(checked 20 times - no reproduce)
> 
> Also we need to print message for reboot action, for that matter
> we can schedule work for it same as for poweroff action as all
> outgoing network packets will be droped after time exhausted.
> 
> Pity that when call panic we will not get modules list as in
> oops, all other relevant info seem to stay in current output.
> 
> https://jira.sw.ru/browse/PSBM-50006
> Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

Acked-by: Kirill Tkhai <ktkhai at virtuozzo.com>

> ---
>  kernel/fence-watchdog.c | 31 +++++++++++++------------------
>  1 file changed, 13 insertions(+), 18 deletions(-)
> 
> diff --git a/kernel/fence-watchdog.c b/kernel/fence-watchdog.c
> index 622cd53..f5c2347f 100644
> --- a/kernel/fence-watchdog.c
> +++ b/kernel/fence-watchdog.c
> @@ -42,36 +42,31 @@ DEFINE_VVAR(volatile unsigned long, fence_wdog_jiffies64) = MAX_U64;
>  static int fence_wdog_action = FENCE_WDOG_CRASH;
>  static atomic_t not_fenced = ATOMIC_INIT(-1);
>  
> -static void do_halt(struct work_struct *dummy)
> +static void do_halt_or_reboot(struct work_struct *dummy)
>  {
>  	printk(KERN_EMERG"fence-watchdog: %s\n",
>  	       action_names[fence_wdog_action]);
> -	kernel_halt();
> -}
> -
> -static DECLARE_WORK(halt_work, do_halt);
> -
> -void fence_wdog_do_fence(void)
> -{
> -	char *killer = NULL;
> -
>  	switch (fence_wdog_action) {
> -	case FENCE_WDOG_CRASH:
> -		panic_on_oops = 1;
> -		wmb();
> -		*killer = 1;
> -		break;
>  	case FENCE_WDOG_REBOOT:
> -		lockdep_off();
> -		local_irq_enable();
>  		emergency_restart();
>  		break;
>  	case FENCE_WDOG_POWEROFF:
> -		schedule_work(&halt_work);
> +		kernel_halt();
>  		break;
>  	}
>  }
>  
> +static DECLARE_WORK(halt_or_reboot_work, do_halt_or_reboot);
> +
> +void fence_wdog_do_fence(void)
> +{
> +	if (fence_wdog_action == FENCE_WDOG_CRASH)
> +		panic("fence-watchdog: %s\n",
> +		      action_names[fence_wdog_action]);
> +	else
> +		schedule_work(&halt_or_reboot_work);
> +}
> +
>  inline int fence_wdog_check_timer(void)
>  {
>  	if (unlikely(get_jiffies_64() > fence_wdog_jiffies64 &&
>