* Oleg Nesterov <o...@redhat.com> [2012-07-08 22:30:08]:
> Kill copy_vma()->uprobe_mmap(new_vma), it is absolutely wrong.
>
> This new_vma was just initialized to represent the new unmapped area,
> [vm_start, vm_end) was returned by get_unmapped_area() in the caller.
>
> This means that uprobe_mmap()->get_user_pages() will fail for sure,
> simply because find_vma() can never succeed. And I verified that
> sys_mremap()->mremap_to() indeed always fails with the wrong ENOMEM
> code if [addr, addr+old_len] is probed.
>
> And why this uprobe_mmap() was added? I believe the intent was wrong.
> Note that the caller is going to do move_page_tables(), all registered
> uprobes are already faulted in, we only change the virtual addresses.
>
> NOTE: However, somehow we need to close the race with uprobe_register()
> which relies on map_info->vaddr. This needs another fix I'll try to do
> later. Probably we need uprobe_mmap() in move_vma() but we can not do
> this right now, this can confuse uprobes_state.counter (which I still
> hope we are going to kill).
>
> Signed-off-by: Oleg Nesterov <o...@redhat.com>
Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
> ---
> mm/mmap.c | 3 ---
> 1 files changed, 0 insertions(+), 3 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 3edfcdf..e5a4614 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -2418,9 +2418,6 @@ struct vm_area_struct *copy_vma(struct vm_area_struct
> **vmap,
> if (new_vma->vm_file) {
> get_file(new_vma->vm_file);
>
> - if (uprobe_mmap(new_vma))
> - goto out_free_mempol;
> -
> if (vma->vm_flags & VM_EXECUTABLE)
> added_exe_file_vma(mm);
> }
> --
> 1.5.5.1
>
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