From: "Danilo Krummrich" <dakr@kernel.org>
To: "Eliot Courtney" <ecourtney@nvidia.com>
Cc: "Gary Guo" <gary@garyguo.net>, <acourbot@nvidia.com>,
<aliceryhl@google.com>, <nouveau@lists.freedesktop.org>,
<dri-devel@lists.freedesktop.org>,
<rust-for-linux@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
"dri-devel" <dri-devel-bounces@lists.freedesktop.org>
Subject: Re: [PATCH] gpu: nova-core: gsp: fix UB in DmaGspMem pointer accessors
Date: Tue, 10 Mar 2026 12:02:10 +0100 [thread overview]
Message-ID: <DGZ1UYLTMFQW.1ZBAMJN70OOQI@kernel.org> (raw)
In-Reply-To: <DGYSTBMF931L.3OV1I4IWUW4ON@nvidia.com>
On Tue Mar 10, 2026 at 4:56 AM CET, Eliot Courtney wrote:
> On Tue Mar 10, 2026 at 11:01 AM JST, Gary Guo wrote:
>>> + pub(in crate::gsp) fn advance_cpu_write_ptr(qs: &CoherentAllocation<GspMem>, count: u32) {
>>> + let wptr = cpu_write_ptr(qs).wrapping_add(count) & MSGQ_NUM_PAGES;
>>
>> Not really related to your change, but this `&` probably require a comment, as
>> it has different behaviour compared to `%` given the `MSGQ_NUM_PAGES` is not
>> power of two. I suppose this is actually intended so there's a way to
>> distinguish between empty and full ring buffer?
>
> This is actually incorrect and I have fixed it here[1]. I think it
> should be merged in drm-rust-next now.
Probably should have been going through -fixes. Anyways, I will fix it up in
this patch too.
> [1]: https://lore.kernel.org/all/20260129-nova-core-cmdq1-v3-0-2ede85493a27@nvidia.com/
next prev parent reply other threads:[~2026-03-10 11:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-09 22:53 [PATCH] gpu: nova-core: gsp: fix UB in DmaGspMem pointer accessors Danilo Krummrich
2026-03-10 2:01 ` Gary Guo
2026-03-10 3:56 ` Eliot Courtney
2026-03-10 11:02 ` Danilo Krummrich [this message]
2026-03-11 12:58 ` Gary Guo
2026-03-11 13:04 ` Danilo Krummrich
2026-03-10 10:58 ` Danilo Krummrich
2026-03-11 12:59 ` Gary Guo
2026-03-11 13:05 ` Danilo Krummrich
2026-03-11 8:01 ` Alexandre Courbot
2026-03-11 19:29 ` Danilo Krummrich
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