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SubjectRe: [PATCH 1/1] mm/madvise: replace ptrace attach requirement for process_madvise
Date
* Suren Baghdasaryan:

> diff --git a/mm/madvise.c b/mm/madvise.c
> index 6a660858784b..c2d600386902 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -1197,12 +1197,22 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
> goto release_task;
> }
>
> - mm = mm_access(task, PTRACE_MODE_ATTACH_FSCREDS);
> + /* Require PTRACE_MODE_READ to avoid leaking ASLR metadata. */
> + mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
> if (IS_ERR_OR_NULL(mm)) {
> ret = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
> goto release_task;
> }

Shouldn't this depend on the requested behavior? Several operations
directly result in observable changes, and go beyond performance tuning.

Thanks,
Florian
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