From: Helge Deller Date: Mon, 4 Oct 2021 22:05:43 +0000 (+0200) Subject: task_stack: Fix end_of_stack() for architectures with upwards-growing stack X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f6ca0ac23202d55bcad44907aa720e7d9ee786fa;p=linux.git task_stack: Fix end_of_stack() for architectures with upwards-growing stack [ Upstream commit 9cc2fa4f4a92ccc6760d764e7341be46ee8aaaa1 ] 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 Signed-off-by: Sasha Levin --- diff --git a/include/linux/sched/task_stack.h b/include/linux/sched/task_stack.h index 2413427e439c7..d10150587d819 100644 --- a/include/linux/sched/task_stack.h +++ b/include/linux/sched/task_stack.h @@ -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)