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From: Asahi Lina <lina@asahilina.net>
To: "Danilo Krummrich" <dakr@kernel.org>,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <benno.lossin@proton.me>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Trevor Gross" <tmgross@umich.edu>
Cc: Janne Grunau <j@jannau.net>,
	rust-for-linux@vger.kernel.org,  linux-kernel@vger.kernel.org,
	asahi@lists.linux.dev,  Asahi Lina <lina@asahilina.net>
Subject: [PATCH] rust: alloc: Fix `ArrayLayout` allocations
Date: Sat, 23 Nov 2024 19:29:38 +0900	[thread overview]
Message-ID: <20241123-rust-fix-arraylayout-v1-1-197e64c95bd4@asahilina.net> (raw)

We were accidentally allocating a layout for the *square* of the object
size due to a variable shadowing mishap.

Fixes memory bloat and page allocation failures in drm/asahi.

Reported-by: Janne Grunau <j@jannau.net>
Fixes: 9e7bbfa18276 ("rust: alloc: introduce `ArrayLayout`")
Signed-off-by: Asahi Lina <lina@asahilina.net>
---
 rust/kernel/alloc/layout.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/alloc/layout.rs b/rust/kernel/alloc/layout.rs
index 7e0c2f46157b772248450a77ff445091e17fdfd7..4b3cd7fdc816c158e63ac74014cbfc0794547e81 100644
--- a/rust/kernel/alloc/layout.rs
+++ b/rust/kernel/alloc/layout.rs
@@ -45,7 +45,7 @@ pub const fn empty() -> Self {
     /// When `len * size_of::<T>()` overflows or when `len * size_of::<T>() > isize::MAX`.
     pub const fn new(len: usize) -> Result<Self, LayoutError> {
         match len.checked_mul(core::mem::size_of::<T>()) {
-            Some(len) if len <= ISIZE_MAX => {
+            Some(size) if size <= ISIZE_MAX => {
                 // INVARIANT: We checked above that `len * size_of::<T>() <= isize::MAX`.
                 Ok(Self {
                     len,

---
base-commit: b2603f8ac8217bc59f5c7f248ac248423b9b99cb
change-id: 20241123-rust-fix-arraylayout-0b1009d89fb7

Cheers,
~~ Lina


             reply	other threads:[~2024-11-23 10:30 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-23 10:29 Asahi Lina [this message]
2024-11-23 10:47 ` Neal Gompa
2024-11-23 17:39 ` Miguel Ojeda
2024-11-23 17:49   ` Miguel Ojeda
2024-11-25 16:20   ` Boqun Feng
2024-11-25 16:26     ` Miguel Ojeda
2024-11-23 20:08 ` Danilo Krummrich
2024-11-23 21:55   ` Janne Grunau
2024-11-24 23:56 ` Miguel Ojeda

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