The branch main has been updated by dougm: URL: https://cgit.FreeBSD.org/src/commit/?id=91b30f7ad22642979b56a56b211843cbd9d35984
commit 91b30f7ad22642979b56a56b211843cbd9d35984 Author: Doug Moore <[email protected]> AuthorDate: 2022-06-30 17:27:33 +0000 Commit: Doug Moore <[email protected]> CommitDate: 2022-06-30 17:35:05 +0000 rb_tree: silence coverity Add comments to RB_INSERT_COLOR to silence coverity warnings about the use of an uninitialized variable. Since other static analyzers will complain too, add a comment to explain why the complaints are unwarranted. Reviewed by: markj MFC after: 3 weeks Differential Revision: https://reviews.freebsd.org/D35671 --- sys/sys/tree.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/sys/sys/tree.h b/sys/sys/tree.h index fb0136a0c69a..553d84e57cc8 100644 --- a/sys/sys/tree.h +++ b/sys/sys/tree.h @@ -462,6 +462,17 @@ struct { \ attr void \ name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \ { \ + /* \ + * Initially, elm is a leaf. Either its parent was previously \ + * a leaf, with two black null children, or an interior node \ + * with a black non-null child and a red null child. The \ + * balance criterion "the rank of any leaf is 1" precludes the \ + * possibility of two red null children for the initial parent. \ + * So the first loop iteration cannot lead to accessing an \ + * uninitialized 'child', and a later iteration can only happen \ + * when a value has been assigned to 'child' in the previous \ + * one. \ + */ \ struct type *child, *parent; \ while ((parent = RB_PARENT(elm, field)) != NULL) { \ if (RB_LEFT(parent, field) == elm) { \ @@ -477,6 +488,7 @@ name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \ } \ if (!RB_RED_RIGHT(elm, field)) { \ RB_FLIP_LEFT(elm, field); \ + /* coverity[uninit_use] */ \ RB_ROTATE_LEFT(head, elm, child, field);\ if (RB_RED_LEFT(child, field)) \ RB_FLIP_RIGHT(elm, field); \ @@ -498,6 +510,7 @@ name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \ } \ if (!RB_RED_LEFT(elm, field)) { \ RB_FLIP_RIGHT(elm, field); \ + /* coverity[uninit_use] */ \ RB_ROTATE_RIGHT(head, elm, child, field);\ if (RB_RED_RIGHT(child, field)) \ RB_FLIP_LEFT(elm, field); \
