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charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2026-06-11 at 10:19 +0200, Peter Zijlstra wrote: >=20 > IOW, the transform totally preserves the limit. If the vlag was bound > before, it must be bound after. >=20 > What am I missing? You're not missing anything. After looking at the code, and tracing through things for much of the afternoon, it turns out the culprit is the cgroup throttle path. Specifically, this bug happened on a 6.16 based kernel, which has the new EEVDF zero_vruntime code, in order to prevent the EEVDF starvation that could happen with the old min_vruntime code, but also still has the old cgroup throttling code. This leaves a code path where lazy dequeue code combined with the cgroup throttling code can result in entity_lag and entity_key reaching ludicrous values, resulting in the overflow. This bug reproduces in about 5 minutes on that 6.16 based kernel, but not with current upstream. Nothing to do upstream, and it looks like there are a few changesets upstream that may be able to fix the issue in the 6.16 based kernel without even needing the clamp from this patch. --=20 All Rights Reversed.