Hi, On 2023/9/11 5:26, Andrew Morton wrote: > On Wed, 6 Sep 2023 10:33:12 +0000 Xiu Jianfeng <xiujianfeng@xxxxxxxxxxxxxxx> wrote: > >> expand_upwards() and expand_downwards() will return -EFAULT if VM_GROWSUP >> or VM_GROWSDOWN is not correctly set in vma->vm_flags, however in >> !CONFIG_STACK_GROWSUP case, expand_stack_locked() returns -EINVAL first >> if !(vma->vm_flags & VM_GROWSDOWN) before calling expand_downwards(), to >> keep the consistency with CONFIG_STACK_GROWSUP case, remove this check. > > What are the user-visible effects of this change? > > Do you believe this fix should be backported into earlier kernel versions? The usages of this function are as bellow: A:fs/exec.c ret = expand_stack_locked(vma, stack_base); if (ret) ret = -EFAULT; or B:mm/memory.c mm/mmap.c if (expand_stack_locked(vma, addr)) return NULL; which means the return value will not propagate to other places, so I believe there is no user-visible effects of this change, and it's unnecessary to backport to earlier versions.
