Re: [PATCH v2] fix mmap return value when vma is merged after call_mmap()

On Thu, 3 Dec 2020 16:53:50 +0800 Liu Zixian liuzixian4@huawei.com wrote:

On success, mmap should return the begin address of newly mapped area, but patch "mm: mmap: merge vma after call_mmap() if possible" set vm_start of newly merged vma to return value addr. Users of mmap will get wrong address if vma is merged after call_mmap(). We fix this by moving the assignment to addr before merging vma.

Let's cc David and Jason, as they commented on v1.

You cc'ed stable@vger.kernel.org on the email, but there's no cc:stable@vger.kernel.org in the changelog tags. There should be.

Has this bug actually been observed at runtime, or is it a theoretical from-code-inspection thing?