* Re: [PATCH] mm: remove duplicated vma->vm_flags check when expanding stack [not found] <20230906103312.645712-1-xiujianfeng@huaweicloud.com> @ 2023-09-10 21:26 ` Andrew Morton 2023-09-11 2:04 ` Xiu Jianfeng 0 siblings, 1 reply; 2+ messages in thread From: Andrew Morton @ 2023-09-10 21:26 UTC (permalink / raw) To: Xiu Jianfeng; +Cc: Liam.Howlett, willy, linux-mm, linux-kernel, xiujianfeng On Wed, 6 Sep 2023 10:33:12 +0000 Xiu Jianfeng <xiujianfeng@huaweicloud.com> 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? ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] mm: remove duplicated vma->vm_flags check when expanding stack 2023-09-10 21:26 ` [PATCH] mm: remove duplicated vma->vm_flags check when expanding stack Andrew Morton @ 2023-09-11 2:04 ` Xiu Jianfeng 0 siblings, 0 replies; 2+ messages in thread From: Xiu Jianfeng @ 2023-09-11 2:04 UTC (permalink / raw) To: Andrew Morton, Xiu Jianfeng; +Cc: Liam.Howlett, willy, linux-mm, linux-kernel Hi, On 2023/9/11 5:26, Andrew Morton wrote: > On Wed, 6 Sep 2023 10:33:12 +0000 Xiu Jianfeng <xiujianfeng@huaweicloud.com> 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. ^ permalink raw reply [flat|nested] 2+ messages in thread
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[not found] <20230906103312.645712-1-xiujianfeng@huaweicloud.com>
2023-09-10 21:26 ` [PATCH] mm: remove duplicated vma->vm_flags check when expanding stack Andrew Morton
2023-09-11 2:04 ` Xiu Jianfeng
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