From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F234ACA5FE8 for ; Sat, 3 Oct 2026 01:33:19 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6D19310E716; Sat, 3 Oct 2026 01:33:19 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="f/RB3EHt"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id DE73710E714; Sat, 3 Oct 2026 01:33:17 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 5CB8160A97; Sat, 3 Oct 2026 01:33:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E90DC1F0089A; Sat, 3 Oct 2026 01:33:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790991197; bh=tRwtVOpXEQqgWSgqNTVcB1+XqGOHmZ/GNHN5nYpi64Q=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=f/RB3EHtr7Oyy8GYV73aXx2SsTUlZDOaT4KcOCMZowVaI9WQZonqrKZ4UWy1z+GMP 4z2EJkWNHyT43Ad3jQDTfcnql8AiC76WaPwmHhVVcE5HLww/cl34lqQmLg3MYvLLEc cXWoG26v0omFySLEfKgXK9drd3W44fEaa7xGqs+daumTdpdiCfolp8Ab/GqLMpUVbN tvdQcEktgbJyOqff/GN+F+hkJgsBRaFKfEDOx0yqSg2q3l1gh2p5nacwv7y9s8egxQ Aig2nz5KlNXB/nss9PmRoOmvs9BUgDEZAb3M+rdID/2UVJaiPTMk4DwPLkkAfRvPFU 01HmZcUEjOfeA== From: sashiko-bot@kernel.org Subject: Re: [PATCH] drm/i915/pmu: convert i915_pmu->lock to raw_spinlock_t from spinlock_t To: "Anubhav Shelat" Cc: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org In-Reply-To: <20261002161137.297365-1-ashelat@redhat.com> References: <20261002161137.297365-1-ashelat@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 03 Oct 2026 01:33:16 +0000 Message-Id: <20261003013316.E90DC1F0089A@smtp.kernel.org> X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] i915/pmu: sleep in atomic (PREEMPT_RT) lock inversion in i915_pmu_= gt_parked() -- commit 4674b42fb5bd16ec1392c65ea4ec0e37639b3618 Author: Anubhav Shelat drm/i915/pmu: convert i915_pmu->lock to raw_spinlock_t from spinlock_t This commit converts the pmu lock from spinlock_t to raw_spinlock_t. The conversion aims to avoid a sleep-in-atomic error on PREEMPT_RT kernels when perf operations are called under a raw spinlock. > diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_= pmu.c > index 1c3bafda9c708..65771e54b9b51 100644 > --- a/drivers/gpu/drm/i915/i915_pmu.c > +++ b/drivers/gpu/drm/i915/i915_pmu.c [ ... ] > @@ -304,7 +304,7 @@ void i915_pmu_gt_parked(struct intel_gt *gt) > if (!pmu->registered) > return; > =20 > - spin_lock_irq(&pmu->lock); > + raw_spin_lock_irq(&pmu->lock); > =20 > park_rc6(gt); [Severity: High] Does this introduce a lock inversion on PREEMPT_RT kernels? The patch converts pmu->lock to raw_spinlock_t, but i915_pmu_gt_parked() ca= lls into a path that acquires a regular spinlock_t while this raw lock is held: i915_pmu_gt_parked() raw_spin_lock_irq(&pmu->lock); park_rc6() __get_rc6() intel_rc6_residency_ns() spin_lock_irqsave(&uncore->lock, flags); Because uncore->lock is still a standard spinlock_t, it can sleep on PREEMP= T_RT kernels. Acquiring it while holding the raw pmu->lock violates the lock hierarchy and can cause a sleep-in-atomic panic during normal power managem= ent operations. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261002161137.2973= 65-1-ashelat@redhat.com?part=3D1