linux-kernel - [PATCH v2] rust: Test page_align usize::MAX boundary edges

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20251230113550.82666-1-bshephar@bne-home.net>
Date: Tue, 30 Dec 2025 21:35:50 +1000
From: bshephar@...-home.net
To: aliceryhl@...gle.com,
	lorenzo.stoakes@...cle.com,
	Liam.Howlett@...cle.com,
	ojeda@...nel.org,
	boqun.feng@...il.com,
	gary@...yguo.net,
	bjorn3_gh@...tonmail.com,
	lossin@...nel.org,
	a.hindborg@...nel.org,
	tmgross@...ch.edu,
	dakr@...nel.org
Cc: linux-mm@...ck.org,
	rust-for-linux@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Brendan Shephard <bshephar@...-home.net>
Subject: [PATCH v2] rust: Test page_align usize::MAX boundary edges

From: Brendan Shephard <bshephar@...-home.net>

Update `page_align` doc tests to test `usize::MAX` boundaries
rather than arbitrary middle of `PAGE_SIZE`.

Signed-off-by: Brendan Shephard <bshephar@...-home.net>
---
This change is a follow-up to:
https://lore.kernel.org/rust-for-linux/CANiq72mLPvB_6Ow3bW5-V4-km=RyA59chQ1g1x9qUt2P-zZweg@mail.gmail.com/

Changes in v2:
- Change test comment back to explicitly mentioning overflow condition
- Updated commit message to remove follow-up comment.

 rust/kernel/page.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/page.rs b/rust/kernel/page.rs
index adecb200c654..c8dafdd843d7 100644
--- a/rust/kernel/page.rs
+++ b/rust/kernel/page.rs
@@ -45,9 +45,10 @@
 /// assert_eq!(page_align(0x1), Some(PAGE_SIZE));
 /// assert_eq!(page_align(PAGE_SIZE + 1), Some(2 * PAGE_SIZE));
 ///
-/// // Requested address causes overflow (returns `None`).
-/// let overflow_addr = usize::MAX - (PAGE_SIZE / 2);
-/// assert_eq!(page_align(overflow_addr), None);
+/// // Requested address causes overflow.
+/// assert_eq!(page_align(usize::MAX - PAGE_SIZE + 1), Some(usize::MAX - PAGE_SIZE + 1));
+/// assert_eq!(page_align(usize::MAX - PAGE_SIZE + 2), None);
+/// assert_eq!(page_align(usize::MAX), None);
 /// ```
 #[inline(always)]
 pub const fn page_align(addr: usize) -> Option<usize> {

base-commit: 7acc70476f14661149774ab88d3fe23d83ba4249
-- 
2.52.0