linux-kernel - Re: [PATCH] rust: alloc: Fix `ArrayLayout` allocations

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>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20241123215522.GB2171629@robin.jannau.net>
Date: Sat, 23 Nov 2024 22:55:22 +0100
From: Janne Grunau <j@...nau.net>
To: Danilo Krummrich <dakr@...nel.org>
Cc: Asahi Lina <lina@...hilina.net>, Miguel Ojeda <ojeda@...nel.org>,
	Alex Gaynor <alex.gaynor@...il.com>,
	Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>,
	Benno Lossin <benno.lossin@...ton.me>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>,
	rust-for-linux@...r.kernel.org, linux-kernel@...r.kernel.org,
	asahi@...ts.linux.dev
Subject: Re: [PATCH] rust: alloc: Fix `ArrayLayout` allocations

On Sat, Nov 23, 2024 at 09:08:35PM +0100, Danilo Krummrich wrote:
> On Sat, Nov 23, 2024 at 07:29:38PM +0900, Asahi Lina wrote:
> > 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@...nau.net>
> > Fixes: 9e7bbfa18276 ("rust: alloc: introduce `ArrayLayout`")
> > Signed-off-by: Asahi Lina <lina@...hilina.net>
> 
> Good catch!
> 
> Acked-by: Danilo Krummrich <dakr@...nel.org>
> 
> (I'm just back from moving and just starting to catch up on what was going on
> in the last few weeks.)
> 
> Is this related to the performance regression that has been observed by Andreas?
> Or did it turn out to be a false positive?

No idea. We noticed KVec allocation errors with page order 4 to 8 under
memory pressure which weren't observed with the previous allocator (or at
least not that easily).

I haven't noticed performance regressions with asahi's usage. glmark2
score was roughly at the expected value.

Janne