2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Manfred Spraul commit 711a49a07f84f914aac26a52143f6e7526571143 upstream. The last patch to lib/idr.c caused a bug if idr_get_new_above() was called on an empty idr. Usually, nodes stay on the same layer. New layers are added to the top of the tree. The exception is idr_get_new_above() on an empty tree: In this case, the new root node is first added on layer 0, then moved upwards. p->layer was not updated. As usual: You shall never rely on the source code comments, they will only mislead you. Signed-off-by: Manfred Spraul Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- lib/idr.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/lib/idr.c +++ b/lib/idr.c @@ -220,8 +220,14 @@ build_up: */ while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { layers++; - if (!p->count) + if (!p->count) { + /* special case: if the tree is currently empty, + * then we grow the tree by moving the top node + * upwards. + */ + p->layer++; continue; + } if (!(new = get_from_free_list(idp))) { /* * The allocation failed. If we built part of -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/