[RFC 04/11] coccicheck: detect hashmap_entry.hash assignment

From: Eric Wong <e@80x24.org>
Date: Sep 8, 2019, 07:49 UTC
Message-ID: <20190908074953.kux7zz4y7iolqko4@whir>
In-Reply-To: <20190826024332.3403-5-e@80x24.org>

Eric Wong <e@80x24.org> wrote:

> By renaming the "hash" field to "_hash", it's easy to spot
> improper initialization of hashmap_entry structs which
> can leave "hashmap_entry.next" uninitialized.

Junio, I'm planning to reroll this series. (Sorry for not following up sooner)

Would you prefer I drop 04/11 "hashmap_entry: detect improper initialization" in favor of the following? Thanks.

---------8<--------
Subject: [PATCH 4/11] coccicheck: detect hashmap_entry.hash assignment

Assigning hashmap_entry.hash manually leaves hashmap_entry.next uninitialized, which can be dangerous once the hashmap_entry is inserted into a hashmap. Detect those assignments and use hashmap_entry_init, instead.

Signed-off-by: Eric Wong <e@80x24.org>
---
 contrib/coccinelle/hashmap.cocci | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 contrib/coccinelle/hashmap.cocci

diff --git a/contrib/coccinelle/hashmap.cocci b/contrib/coccinelle/hashmap.cocci
new file mode 100644
index 0000000000..d69e120ccf
--- /dev/null
+++ b/contrib/coccinelle/hashmap.cocci
@@ -0,0 +1,16 @@
+@ hashmap_entry_init_usage @
+expression E;
+struct hashmap_entry HME;
+@@
+- HME.hash = E;
++ hashmap_entry_init(&HME, E);
+
+@@
+identifier f !~ "^hashmap_entry_init$";
+expression E;
+struct hashmap_entry *HMEP;
+@@
+  f(...) {<...
+- HMEP->hash = E;
++ hashmap_entry_init(HMEP, E);
+  ...>}