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Commit 676758bd authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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[PATCH] msync: fix return value 



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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 707c21c8

mm/msync.c

+7 −7
Original line number Diff line number Diff line
@@ -146,7 +146,8 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags) 
{

	unsigned long end;

	struct vm_area_struct *vma;

	int unmapped_error, error = -EINVAL;

	int unmapped_error = 0;

	int error = -EINVAL;

	int done = 0;



	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)

		current->flags |= PF_SYNCWRITE;

	vma = find_vma(current->mm, start);

	unmapped_error = 0;

	if (!vma) {

		error = -ENOMEM;

		goto out_unlock;

	}

	do {

		unsigned long nr_pages_dirtied = 0;

		struct file *file;



		/* Still start < end. */

		error = -ENOMEM;

		if (!vma)

			goto out_unlock;

		/* Here start < vma->vm_end. */

		if (start < vma->vm_start) {

			unmapped_error = -ENOMEM;
@@ -239,7 +239,7 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags) 
		} else {

			vma = vma->vm_next;

		}

	} while (!done);

	} while (vma && !done);

out_unlock:

	current->flags &= ~PF_SYNCWRITE;

	up_read(&current->mm->mmap_sem);