[PATCH 1/2] sched: fix thread_union::task visibility

[PATCH 1/2] sched: fix thread_union::task visibility

[Masahiro Yamada]

When CONFIG_ARCH_TASK_STRUCT_ON_STACK=y (i.e. ARCH=ia64), task_struct
and the thread stack are shared.

The ifdef condition of CONFIG_ARCH_TASK_STRUCT_ON_STACK is opposite.

Now that the init thread stack is constructed by the linker script,
this is not a practical problem, but let's fix the code just in case.

Fixes: 0500871f21b2 ("Construct init thread stack in the linker script rather than by union")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 include/linux/sched.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index b62e6aaf28f0..6d6c4d38c063 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1674,7 +1674,7 @@ extern void ia64_set_curr_task(int cpu, struct task_struct *p);
 void yield(void);
 
 union thread_union {
-#ifndef CONFIG_ARCH_TASK_STRUCT_ON_STACK
+#ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
 	struct task_struct task;
 #endif
 #ifndef CONFIG_THREAD_INFO_IN_TASK
-- 
2.25.1

[PATCH 2/2] init: annotate init_task as __init_task_data for all arches

[Masahiro Yamada]

__init_task_data is no-op when CONFIG_ARCH_TASK_STRUCT_ON_STACK=n,
so you can always annotate init_task as __init_task_data.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 init/init_task.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/init/init_task.c b/init/init_task.c
index 15089d15010a..0110b2941c4d 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -61,11 +61,7 @@ unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)]
  * Set up the first task table, touch at your own risk!. Base=0,
  * limit=0x1fffff (=2MB)
  */
-struct task_struct init_task
-#ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
-	__init_task_data
-#endif
-= {
+struct task_struct init_task __init_task_data = {
 #ifdef CONFIG_THREAD_INFO_IN_TASK
 	.thread_info	= INIT_THREAD_INFO(init_task),
 	.stack_refcount	= REFCOUNT_INIT(1),
-- 
2.25.1