task_stack: Fix end_of_stack() for architectures with upwards-growing stack

The function end_of_stack() returns a pointer to the last entry of a
stack. For architectures like parisc where the stack grows upwards
return the pointer to the highest address in the stack.

Without this change I faced a crash on parisc, because the stackleak
functionality wrote STACKLEAK_POISON to the lowest address and thus
overwrote the first 4 bytes of the task_struct which included the
TIF_FLAGS.

Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Helge Deller 2021-10-05 00:05:43 +02:00
parent f06d6e92c8
commit 9cc2fa4f4a

View File

@ -25,7 +25,11 @@ static inline void *task_stack_page(const struct task_struct *task)
static inline unsigned long *end_of_stack(const struct task_struct *task)
{
#ifdef CONFIG_STACK_GROWSUP
return (unsigned long *)((unsigned long)task->stack + THREAD_SIZE) - 1;
#else
return task->stack;
#endif
}
#elif !defined(__HAVE_THREAD_FUNCTIONS)