From nobody Fri Dec 19 20:15:33 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A90BF2F83BC; Fri, 7 Nov 2025 18:19:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762539565; cv=none; b=TY9lpCJKWZQxSLTYLhxo800Q5dHYM9Izhj0ILsbEUxLpVIxe5S5DnM7hbbLyCeLre2k4vdwKTW2fj4BYi54Gj3fXo1PGjUE4qGKjob+1k3IJg79OhW7zkzNI9RkuiVNyMweCAC5DyTT57lN6ogjCkf21+PJFovNHotz0O07jxt0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762539565; c=relaxed/simple; bh=M0slxHbV7wZavtVVRNUtrb7s9AgZM4xj2aLlMwjHvpY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=S417zqlHVBqBS7LOjDdJyLoufxkHLSTlWzZce1ljTpRfzvGCeYD0+Xr1dTLpNohYX9tURyzGOwdjrLux6GuF79+M/2OWQspzIF8sjJVKxdVulOvBpxETUcSpxqsWKBUPREHKC2BPGdGzmUioLIvdnD/qa4xytH6D3FVf+OefaO8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FYmAk4es; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FYmAk4es" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 11063C4CEF8; Fri, 7 Nov 2025 18:19:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762539565; bh=M0slxHbV7wZavtVVRNUtrb7s9AgZM4xj2aLlMwjHvpY=; h=From:To:Cc:Subject:Date:From; b=FYmAk4es9c1YbrK7bGuyXUOmyFvwLEzMQjpypFdIFq3wc7B+3diQrFhVZf4CIyDNj x1Lm5EaRyKfgedBRev3JhqXB8fWmpTBpyCQb9j/GmVSDXjn6u2XJPXyz2xEQAkLN91 dNLGAECVfJhHsiwQtrxOgXwtyo6CSg0r7m2ujN+n/vh7gfTewFlvx7/clkqKXKZEX+ S+kW8WIeHCBQ3Fi0ejf4XqsrVLXG/9ydqE9EjuAbXoQ/SC3QiV5r6sU4x0CPRhwh4b C4ev+KpUt0GRfOoSQk57KPqa0xXhOy8ebY9VHkP0ojZ2R7aIuE+Jh0qqDK/ZNPXrM3 uyQNvRc6QEdNA== From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Daniel Lezcano , Artem Bityutskiy Subject: [PATCH v1] cpuidle: Add sanity check for exit latency and target residency Date: Fri, 07 Nov 2025 19:19:21 +0100 Message-ID: <5939579.DvuYhMxLoT@rafael.j.wysocki> Organization: Linux Kernel Development Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Rafael J. Wysocki Make __cpuidle_driver_init() sanitize CPU idle states so that the exit latency of a given state is not greater than its target residency which would break cpuidle assumptions. Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/driver.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -193,6 +193,16 @@ static void __cpuidle_driver_init(struct s->exit_latency_ns =3D 0; else s->exit_latency =3D div_u64(s->exit_latency_ns, NSEC_PER_USEC); + + /* + * Ensure that the exit latency of a CPU idle state does not + * exceed its target residency which is assumed in cpuidle in + * multiple places. + */ + if (s->exit_latency_ns > s->target_residency_ns) { + s->target_residency_ns =3D s->exit_latency_ns; + s->target_residency =3D s->exit_latency; + } } }