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[PATCH] msync: fix return value

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msync() does a strange thing.  Essentially:

	vma = find_vma();
	for ( ; ; ) {
		if (!vma)
			return -ENOMEM;
		...
		vma = vma->vm_next;
	}

so an msync() request which starts within or before a valid VMA and which ends
within or beyond the final VMA will incorrectly return -ENOMEM.

Fix.

Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andrew Morton 2006-03-24 03:18:14 -08:00 committed by Linus Torvalds
parent 707c21c848
commit 676758bdb7
1 changed files with 7 additions and 7 deletions
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14
mm/msync.c
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@ -146,7 +146,8 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
{ {
unsigned long end; unsigned long end;
struct vm_area_struct *vma; struct vm_area_struct *vma;
int unmapped_error, error = -EINVAL; int unmapped_error = 0;
int error = -EINVAL;
int done = 0; int done = 0;
if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
@ -171,15 +172,14 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
if (flags & MS_SYNC) if (flags & MS_SYNC)
current->flags |= PF_SYNCWRITE; current->flags |= PF_SYNCWRITE;
vma = find_vma(current->mm, start); vma = find_vma(current->mm, start);
unmapped_error = 0; if (!vma) {
error = -ENOMEM;
goto out_unlock;
}
do { do {
unsigned long nr_pages_dirtied = 0; unsigned long nr_pages_dirtied = 0;
struct file *file; struct file *file;
/* Still start < end. */
error = -ENOMEM;
if (!vma)
goto out_unlock;
/* Here start < vma->vm_end. */ /* Here start < vma->vm_end. */
if (start < vma->vm_start) { if (start < vma->vm_start) {
unmapped_error = -ENOMEM; unmapped_error = -ENOMEM;
@ -239,7 +239,7 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
} else { } else {
vma = vma->vm_next; vma = vma->vm_next;
} }
} while (!done); } while (vma && !done);
out_unlock: out_unlock:
current->flags &= ~PF_SYNCWRITE; current->flags &= ~PF_SYNCWRITE;
up_read(&current->mm->mmap_sem); up_read(&current->mm->mmap_sem);