From fb1bf1067de979c89ae33589e0466d6ce0dde204 Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Sat, 15 Mar 2025 16:43:02 +0100 Subject: [PATCH] rust: alloc: add missing invariant in Vec::set_len() When setting a new length, we have to justify that the set length represents the exact number of elements stored in the vector. Reviewed-by: Benno Lossin Reported-by: Alice Ryhl Closes: https://lore.kernel.org/rust-for-linux/20250311-iov-iter-v1-4-f6c9134ea824@google.com Fixes: 2aac4cd7dae3 ("rust: alloc: implement kernel `Vec` type") Link: https://lore.kernel.org/r/20250315154436.65065-2-dakr@kernel.org Signed-off-by: Danilo Krummrich --- rust/kernel/alloc/kvec.rs | 3 +++ 1 file changed, 3 insertions(+) diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs index ae9d072741ce..b01dabfe35aa 100644 --- a/rust/kernel/alloc/kvec.rs +++ b/rust/kernel/alloc/kvec.rs @@ -193,6 +193,9 @@ where #[inline] pub unsafe fn set_len(&mut self, new_len: usize) { debug_assert!(new_len <= self.capacity()); + + // INVARIANT: By the safety requirements of this method `new_len` represents the exact + // number of elements stored within `self`. self.len = new_len; } -- 2.25.1