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Commit 45f49bce authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: avoid NULL pointer deref in try_release_extent_buffer 



If we fail to find a pointer in the radix tree, don't try
to deref the NULL one we do have.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent a1b075d2

fs/btrfs/extent_io.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -3837,8 +3837,10 @@ int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page) 




	spin_lock(&tree->buffer_lock);

	spin_lock(&tree->buffer_lock);

	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);

	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);

	if (!eb)

	if (!eb) {

		goto out;

		spin_unlock(&tree->buffer_lock);

		return ret;

	}





	if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {

	if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {

		ret = 0;

		ret = 0;