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[PATCH] fix VmSize and VmData after mremap

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mremap's move_vma is applying __vm_stat_account to the old vma which may
have already been freed: move it to just before the do_munmap.

mremapping to and fro with CONFIG_DEBUG_SLAB=y showed /proc/<pid>/status
VmSize and VmData wrapping just like in kernel bugzilla #4842, and fixed by
this patch - worth including in 2.6.13, though not yet confirmed that it
fixes that specific report from Frank van Maarseveen.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Hugh Dickins 2005-08-04 13:07:09 -07:00 committed by Linus Torvalds
parent e234f35c54
commit 1c5ad84516
1 changed files with 1 additions and 1 deletions
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mm/mremap.c
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@ -229,6 +229,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
* since do_munmap() will decrement it by old_len == new_len * since do_munmap() will decrement it by old_len == new_len
*/ */
mm->total_vm += new_len >> PAGE_SHIFT; mm->total_vm += new_len >> PAGE_SHIFT;
__vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
if (do_munmap(mm, old_addr, old_len) < 0) { if (do_munmap(mm, old_addr, old_len) < 0) {
/* OOM: unable to split vma, just get accounts right */ /* OOM: unable to split vma, just get accounts right */
@ -243,7 +244,6 @@ static unsigned long move_vma(struct vm_area_struct *vma,
vma->vm_next->vm_flags |= VM_ACCOUNT; vma->vm_next->vm_flags |= VM_ACCOUNT;
} }
__vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
if (vm_flags & VM_LOCKED) { if (vm_flags & VM_LOCKED) {
mm->locked_vm += new_len >> PAGE_SHIFT; mm->locked_vm += new_len >> PAGE_SHIFT;
if (new_len > old_len) if (new_len > old_len)