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Date: Mon, 06 Jul 2026 13:40:40 -1000
Message-ID: <f6b4606f1fc53cbaa2ee9ea314849374@kernel.org>
From: Tejun Heo <tj@kernel.org>
To: sashiko-bot@kernel.org
Cc: sched-ext@lists.linux.dev
Subject: Re: [PATCH v2 sched_ext/for-7.3 15/36] sched_ext: Add scx_cmask_ref for validated arena cmask access
In-Reply-To: <20260706015840.5CD561F000E9@smtp.kernel.org>
References: <20260706014058.439853-1-tj@kernel.org> <20260706014058.439853-16-tj@kernel.org> <20260706015840.5CD561F000E9@smtp.kernel.org>
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On Mon, 06 Jul 2026 01:58:39 +0000, sashiko-bot wrote:
> - [High] Non-atomic Read-Modify-Write in `scx_cmask_ref_or` and `scx_cmask_ref_copy` clobbers concurrent BPF updates to adjacent bits.

False positive. The read-modify-write targets the per-call kernel output
buffer while the calling BPF thread is blocked in the synchronous kfunc; the
authoritative cap state is kernel-owned under pshard->lock. The non-atomic
word ops are documented as tearing-only on that output, not a correctness
race.