generic-ipi: Initialize call_single_queue before enabling interrupt

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

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 <[email protected]>

---
 include/linux/smp.h |    5 ++++-
 init/main.c         |    1 +
 kernel/smp.c        |    5 +----
 3 files changed, 6 insertions(+), 5 deletions(-)

include/linux/smp.h +4 -1

index 74243c8..4fb3eac 100644
@@ -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,

init/main.c +1 -0

index 4a9479e..12821d1 100644
@@ -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");

kernel/smp.c +1 -1

index 73a1951..fb67dfa 100644
@@ -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;

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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 <[email protected]>

---
 include/linux/smp.h |    5 ++++-
 init/main.c         |    1 +
 kernel/smp.c        |    5 +----
 3 files changed, 6 insertions(+), 5 deletions(-)

include/linux/smp.h +4 -1

index 74243c8..4fb3eac 100644
@@ -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,

init/main.c +0 -0

index 4a9479e..12821d1 100644

init/main.c +0 -0

 	if (!irqs_disabled())
 		printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 				 "enabled early\n");

kernel/smp.c +1 -1

index 73a1951..fb67dfa 100644
@@ -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;

Quoted 83 lines · Takao Indoh

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 <[email protected]>

---
 include/linux/smp.h |    5 ++++-
 init/main.c         |    1 +
 kernel/smp.c        |    5 +----
 3 files changed, 6 insertions(+), 5 deletions(-)

include/linux/smp.h +4 -1

index 74243c8..4fb3eac 100644
@@ -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,

init/main.c +0 -0

index 4a9479e..12821d1 100644

init/main.c asmlinkage void __init start_kernel(void) · line 542

Quoted 4 lines

init/main.c +1 -0

@@ -539,6 +539,7 @@ asmlinkage void __init start_kernel(void)
 	timekeeping_init();
 	time_init();
 	profile_init();
+	call_function_init();

Takao,

So by calling this function before we enable interrupts we have made sure that per cpu call_single_queue has been initialized and q->list also has been initiliazed and it is an empty list now.

After enabling the interrupts, I am assuming we will call generic_smp_call_function_single_interrupt().

this function does.

       raw_spin_lock(&q->lock);
       list_replace_init(&q->list, &list);
       raw_spin_unlock(&q->lock);

       while (!list_empty(&list)) {
               struct call_single_data *data;

               data = list_entry(list.next, struct call_single_data,
list);
               list_del(&data->list);

Looking at the code of list_replace_init(), I think we will have odd results if q->list is empty. Looks like list->next will be pointing to &q->list?

IIUC, q->list sould be empty when we get pending IPI from previous kernel because any function scheduled for execution must have been inserted on previous kernel's data structures and here we are building fresh data structures.

If that is the case, I think above code should have weared interaction. We should think that "list" is not empty and try to execute a data item q->list which is actually not a data item.

What am I missing here. After your patch, have to debugged it and noticed how list_replace_init() does on empty lists and what's the result of list_empty(list)?

Thanks
Vivek

Quoted 28 lines

init/main.c +0 -0

 	if (!irqs_disabled())
 		printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 				 "enabled early\n");

kernel/smp.c +1 -1

index 73a1951..fb67dfa 100644
@@ -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();

kernel/smp.c +0 -3

 	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

Quoted 120 lines · Vivek Goyal

Quoted 83 lines · Takao Indoh

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 <[email protected]>

---
 include/linux/smp.h |    5 ++++-
 init/main.c         |    1 +
 kernel/smp.c        |    5 +----
 3 files changed, 6 insertions(+), 5 deletions(-)

include/linux/smp.h +4 -1

index 74243c8..4fb3eac 100644
@@ -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,

init/main.c +0 -0

index 4a9479e..12821d1 100644

init/main.c asmlinkage void __init start_kernel(void) · line 542

Quoted 4 lines

init/main.c +1 -0

@@ -539,6 +539,7 @@ asmlinkage void __init start_kernel(void)
 	timekeeping_init();
 	time_init();
 	profile_init();
+	call_function_init();

Takao,

So by calling this function before we enable interrupts we have made sure that per cpu call_single_queue has been initialized and q->list also has been initiliazed and it is an empty list now.

After enabling the interrupts, I am assuming we will call generic_smp_call_function_single_interrupt().

this function does.

       raw_spin_lock(&q->lock);
       list_replace_init(&q->list, &list);
       raw_spin_unlock(&q->lock);

       while (!list_empty(&list)) {
               struct call_single_data *data;

               data = list_entry(list.next, struct call_single_data,
list);
               list_del(&data->list);

Looking at the code of list_replace_init(), I think we will have odd results if q->list is empty. Looks like list->next will be pointing to &q->list?

IIUC, q->list sould be empty when we get pending IPI from previous kernel because any function scheduled for execution must have been inserted on previous kernel's data structures and here we are building fresh data structures.

Quoted 7 lines

If that is the case, I think above code should have weared interaction. We should think that "list" is not empty and try to execute a data item q->list which is actually not a data item.

What am I missing here. After your patch, have to debugged it and noticed how list_replace_init() does on empty lists and what's the result of list_empty(list)?

When list_replace_init(&q->list, &list) is called, they are changed as followed.

/* list_replace */
(A) &list->next = &q->list->next;
(B) &list->next->prev = &list;
(C) &list->prev = &q->list->prev;
(D) &list->prev->next = &list;

/* INIT_LIST_HEAD */
(E) &q->list->next = &q->list;
(F) &q->list->prev = &q->list;

So, if q->list is empty, each list is changed like this.

(Initial state)
list.next ==> &list
list.prev ==> &list
q->list.next ==> &q->list
q->list.prev ==> &q->list

(A)
list.next ==> &q->list
list.prev ==> &list
q->list.next ==> &q->list
q->list.prev ==> &q->list

(B)
list.next ==> &q->list
list.prev ==> &list
q->list.next ==> &q->list
q->list.prev ==> &list

(C)
list.next ==> &q->list
list.prev ==> &list
q->list.next ==> &q->list
q->list.prev ==> &list

(D)
list.next ==> &list
list.prev ==> &list
q->list.next ==> &q->list
q->list.prev ==> &list

(E)
list.next ==> &list
list.prev ==> &list
q->list.next ==> &q->list
q->list.prev ==> &list

(F)
list.next ==> &list
list.prev ==> &list
q->list.next ==> &q->list
q->list.prev ==> &q->list

So, list_empty(list)? is always false, if I am not missing something.

Quoted 34 lines

Thanks
Vivek

Quoted 28 lines

init/main.c +0 -0

 	if (!irqs_disabled())
 		printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 				 "enabled early\n");

kernel/smp.c +1 -1

index 73a1951..fb67dfa 100644
@@ -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();

kernel/smp.c +0 -3

 	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

Quoted 46 lines · Takao Indoh

Quoted 44 lines · Vivek Goyal

Quoted 43 lines · Takao Indoh

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 <[email protected]>

Quoted 1 line

So, list_empty(list)? is always false, if I am not missing something.

No, list_empty(list)? is always *true*.

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 <[email protected]>

---

include/linux/smp.h |    5 ++++-
init/main.c         |    1 +
kernel/smp.c        |    5 +----
3 files changed, 6 insertions(+), 5 deletions(-)

include/linux/smp.h +4 -1

index 74243c8..4fb3eac 100644
@@ -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,

init/main.c +1 -0

index 4a9479e..12821d1 100644
@@ -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");

kernel/smp.c +1 -1

index 73a1951..fb67dfa 100644
@@ -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;

kernel/smp.c +0 -3

@@ -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

Just a reminder...

Thanks for acks, but I'm still waiting for inclusion. I tested 3.0.0-rc3 and kdump still failed due to pending IPI from 1st kernel. Need this patch to fix it.

Quoted 5 lines · Takao Indoh

Just a reminder...

Thanks for acks, but I'm still waiting for inclusion. I tested 3.0.0-rc3 and kdump still failed due to pending IPI from 1st kernel. Need this patch to fix it.

For any future patch that has a review discussion (like this one) please collect Acks and resend the patch with the acks included once the discussion results in a final patch, otherwise maintainers might skip the patch as "still being reviewed".

I've collected the acks here and started testing your patch.

Thanks,

Ingo