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    SubjectRe: [PATCH 6/7] mm: kill vma flag VM_EXECUTABLE
    On Mon, Apr 02, 2012 at 04:48:21PM +0200, Oleg Nesterov wrote:
    > On 04/02, Konstantin Khlebnikov wrote:
    > >
    > > In this patch I leave mm->exe_file lockless.
    > > After exec/fork we can change it only for current task and only if mm->mm_users == 1.
    > >
    > > something like this:
    > >
    > > task_lock(current);
    >
    > OK, this protects against the race with get_task_mm()
    >
    > > if (atomic_read(&current->mm->mm_users) == 1)
    >
    > this means PR_SET_MM_EXE_FILE can fail simply because someone did
    > get_task_mm(). Or the caller is multithreaded.

    So it leads to the same question -- do we *really* need the PR_SET_MM_EXE_FILE
    to be one-shot action? Yeah, I know, we agreed that one-shot is better than
    anything else from sysadmin perspective and such, but maybe I could introduce
    a special capability bit for c/r and allow a program which has such cap to modify
    exe-file without checkin mm_users?

    /me hides

    >
    > > set_mm_exe_file(current->mm, new_file);
    >
    > No, fput() can sleep.

    Sure, it was just "something like" as Konstantin stated, thanks anyway ;)

    Cyrill


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