| Date | Sat, 15 Oct 2011 21:01:31 +0200 | From | Oleg Nesterov <> | Subject | [PATCH 4/X] uprobes: xol_add_vma: misc cleanups |
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1. get_task_mm(current)/mmput is not needed, we can use ->mm directly.
It can't be NULL or use_mm'ed(), otherwise we are buggy anyway.
2. use IS_ERR_VALUE() after do_mmap_pgoff().
3. No need to read vma->vm_start, it must be equal to addr returned by do_mmap_pgoff().
4. No need to pass vmas => &vma to get_user_pages(). --- kernel/uprobes.c | 13 +++++-------- 1 files changed, 5 insertions(+), 8 deletions(-)
diff --git a/kernel/uprobes.c b/kernel/uprobes.c index 6fe2b20..5c2554c 100644 --- a/kernel/uprobes.c +++ b/kernel/uprobes.c @@ -1051,9 +1051,7 @@ static int xol_add_vma(struct uprobes_xol_area *area) unsigned long addr; int ret; - mm = get_task_mm(current); - if (!mm) - return -ESRCH; + mm = current->mm; down_write(&mm->mmap_sem); ret = -EALREADY; @@ -1076,24 +1074,23 @@ static int xol_add_vma(struct uprobes_xol_area *area) addr = do_mmap_pgoff(NULL, addr, PAGE_SIZE, PROT_EXEC, MAP_PRIVATE, 0); revert_creds(curr_cred); - if (addr & ~PAGE_MASK) + if (IS_ERR_VALUE(addr)) goto fail; vma = find_vma(mm, addr); /* Don't expand vma on mremap(). */ vma->vm_flags |= VM_DONTEXPAND | VM_DONTCOPY; - area->vaddr = vma->vm_start; - if (get_user_pages(current, mm, area->vaddr, 1, 1, 1, &area->page, - &vma) != 1) { + if (get_user_pages(current, mm, addr, 1, 1, 1, + &area->page, NULL) != 1) { do_munmap(mm, addr, PAGE_SIZE); goto fail; } + area->vaddr = addr; mm->uprobes_xol_area = area; ret = 0; fail: up_write(&mm->mmap_sem); - mmput(mm); return ret; } -- 1.5.5.1
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