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mm: fix uninitialized variables for find_vma_prepare callers 

gcc 4.3.0 correctly emits the following warnings.
When a vma covering addr is found, find_vma_prepare indeed returns without
setting pprev, rb_link, and rb_parent.

  mm/mmap.c: In function `insert_vm_struct':
  mm/mmap.c:2085: warning: `rb_parent' may be used uninitialized in this function
  mm/mmap.c:2085: warning: `rb_link' may be used uninitialized in this function
  mm/mmap.c:2084: warning: `prev' may be used uninitialized in this function
  mm/mmap.c: In function `copy_vma':
  mm/mmap.c:2124: warning: `rb_parent' may be used uninitialized in this function
  mm/mmap.c:2124: warning: `rb_link' may be used uninitialized in this function
  mm/mmap.c:2123: warning: `prev' may be used uninitialized in this function
  mm/mmap.c: In function `do_brk':
  mm/mmap.c:1951: warning: `rb_parent' may be used uninitialized in this function
  mm/mmap.c:1951: warning: `rb_link' may be used uninitialized in this function
  mm/mmap.c:1949: warning: `prev' may be used uninitialized in this function
  mm/mmap.c: In function `mmap_region':
  mm/mmap.c:1092: warning: `rb_parent' may be used uninitialized in this function
  mm/mmap.c:1092: warning: `rb_link' may be used uninitialized in this function
  mm/mmap.c:1089: warning: `prev' may be used uninitialized in this function

Hugh adds: in fact, none of find_vma_prepare's callers use those values
when a vma is found to be already covering addr, it's either an error or
an occasion to munmap and repeat.  Okay, let's quieten the compiler (but I
would prefer it if pprev, rb_link and rb_parent were meaningful in that
case, rather than whatever's in them from descending the tree).

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: "Ryan Hope" <rmh3093@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Benny Halevy 2008-08-05 13:01:41 -07:00 committed by Linus Torvalds
parent bf1db69fbf
commit dfe195fb79
1 changed files with 1 additions and 1 deletions
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2
mm/mmap.c
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@ -370,7 +370,7 @@ find_vma_prepare(struct mm_struct *mm, unsigned long addr,
if (vma_tmp->vm_end > addr) {
vma = vma_tmp;
if (vma_tmp->vm_start <= addr)
return vma;
break;
__rb_link = &__rb_parent->rb_left;
} else {
rb_prev = __rb_parent;