Re: [PATCH v2] generic-ipi: Initialize call_single_queue beforeenabling interrupt

[Neil Horman]

On Tue, Mar 29, 2011 at 12:35:04PM -0400, Takao Indoh wrote:
> Hi all,
> 
> This patch renames init_call_single_data() to call_function_init() and
> calls it in start_kernel() so that call_single_queue can be initialized
> before enabling interrupt.
> 
> There is a problem that kdump(2nd kernel) sometimes hangs up due to
> pending IPI from 1st kernel. Kernel panic occurs because IPI comes
> before call_single_queue is initialized. The details are as follows.
> (1) 2nd kernel boot up
> (2) A pending IPI from 1st kernel comes when irqs are first enabled
>     in start_kernel().
> (3) Kernel tries to handle the interrupt, but call_single_queue is not
>     initialized yet at this point. As a result, in the
>     generic_smp_call_function_single_interrupt(), NULL pointer
>     dereference occurs when list_replace_init() tries to access
>     &q->list.next.
> Therefore this patch changes the name of init_call_single_data() to
> call_function_init() and calls it before local_irq_enable() in
> start_kernel().
> 
> v2:
> - Rename init_call_single_data() to call_function_init() and calls it in
>   start_kernel()
> - Change insert position in start_kernel().
> - Adjust for CONFIG_SMP/CONFIG_USE_GENERIC_SMP_HELPERS options
> - Rebased to Linus's latest tree
> 
> v1:
> https://lkml.org/lkml/2011/3/25/317
> - Divide init_call_single_data() into two functions,
>    o init_call_single_data: initialize call_single_queue
>    o init_hotplug_cfd: initialize hotplug_cfd_notifier
>   And call init_call_single_data before local_irq_enable() in
>   start_kernel().
> 
> v0:
> https://lkml.org/lkml/2011/3/23/417
> - In generic_smp_call_function_single_interrupt(), check if
>   call_single_queue was initialized or not, and just return if not
>   initialized.
> 
> Signed-off-by: Takao Indoh <indou.takao@xxxxxxxxxxxxxx>
> ---
>  include/linux/smp.h |    5 ++++-
>  init/main.c         |    1 +
>  kernel/smp.c        |    5 +----
>  3 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/smp.h b/include/linux/smp.h
> index 74243c8..4fb3eac 100644
> --- a/include/linux/smp.h
> +++ b/include/linux/smp.h
> @@ -85,12 +85,15 @@ int smp_call_function_any(const struct cpumask *mask,
>   * Generic and arch helpers
>   */
>  #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
> +void __init call_function_init(void);
>  void generic_smp_call_function_single_interrupt(void);
>  void generic_smp_call_function_interrupt(void);
>  void ipi_call_lock(void);
>  void ipi_call_unlock(void);
>  void ipi_call_lock_irq(void);
>  void ipi_call_unlock_irq(void);
> +#else
> +static inline void call_function_init(void) { }
>  #endif
>  
>  /*
> @@ -144,7 +147,7 @@ static inline void smp_send_reschedule(int cpu) { }
>  #define smp_prepare_boot_cpu()			do {} while (0)
>  #define smp_call_function_many(mask, func, info, wait) \
>  			(up_smp_call_function(func, info))
> -static inline void init_call_single_data(void) { }
> +static inline void call_function_init(void) { }
>  
>  static inline int
>  smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
> diff --git a/init/main.c b/init/main.c
> index 4a9479e..12821d1 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -539,6 +539,7 @@ asmlinkage void __init start_kernel(void)
>  	timekeeping_init();
>  	time_init();
>  	profile_init();
> +	call_function_init();
>  	if (!irqs_disabled())
>  		printk(KERN_CRIT "start_kernel(): bug: interrupts were "
>  				 "enabled early\n");
> diff --git a/kernel/smp.c b/kernel/smp.c
> index 73a1951..fb67dfa 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -74,7 +74,7 @@ static struct notifier_block __cpuinitdata hotplug_cfd_notifier = {
>  	.notifier_call		= hotplug_cfd,
>  };
>  
> -static int __cpuinit init_call_single_data(void)
> +void __init call_function_init(void)
>  {
>  	void *cpu = (void *)(long)smp_processor_id();
>  	int i;
> @@ -88,10 +88,7 @@ static int __cpuinit init_call_single_data(void)
>  
>  	hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu);
>  	register_cpu_notifier(&hotplug_cfd_notifier);
> -
> -	return 0;
>  }
> -early_initcall(init_call_single_data);
>  
>  /*
>   * csd_lock/csd_unlock used to serialize access to per-cpu csd resources
> 
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>

> _______________________________________________
> kexec mailing list
> kexec@xxxxxxxxxxxxxxxxxxx
> http://lists.infradead.org/mailman/listinfo/kexec
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/