Commit 1c5ad845 authored Aug 04, 2005 by Hugh Dickins Committed by Linus Torvalds Aug 04, 2005

[PATCH] fix VmSize and VmData after mremap



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>

parent e234f35c

mm/mremap.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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
		*/
		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) {
		/* 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;
		}

		__vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
		if (vm_flags & VM_LOCKED) {
		mm->locked_vm += new_len >> PAGE_SHIFT;
		if (new_len > old_len)

Admin message