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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD384C10F27 for ; Mon, 9 Mar 2020 12:54:15 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9B50C205ED for ; Mon, 9 Mar 2020 12:54:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9B50C205ED Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3D79489CA8; Mon, 9 Mar 2020 12:54:15 +0000 (UTC) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 41DD889CA8 for ; Mon, 9 Mar 2020 12:54:13 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Mar 2020 05:54:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,533,1574150400"; d="scan'208";a="235588942" Received: from gaia.fi.intel.com ([10.237.72.192]) by fmsmga008.fm.intel.com with ESMTP; 09 Mar 2020 05:54:11 -0700 Received: by gaia.fi.intel.com (Postfix, from userid 1000) id E8A985C1DD1; Mon, 9 Mar 2020 14:52:50 +0200 (EET) From: Mika Kuoppala To: Chris Wilson , intel-gfx@lists.freedesktop.org In-Reply-To: <20200309113623.24208-1-chris@chris-wilson.co.uk> References: <20200309113623.24208-1-chris@chris-wilson.co.uk> Date: Mon, 09 Mar 2020 14:52:50 +0200 Message-ID: <87pndl3d25.fsf@gaia.fi.intel.com> MIME-Version: 1.0 Subject: Re: [Intel-gfx] [PATCH] drm/i915/gt: Mark up intel_rps.active for racy reads 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Chris Wilson writes: > We read the current state of intel_rps.active outside of the lock, so > mark up the racy access. > > [ 525.037073] BUG: KCSAN: data-race in intel_rps_boost [i915] / intel_rps_park [i915] > [ 525.037091] > [ 525.037103] write to 0xffff8881f145efa1 of 1 bytes by task 192 on cpu 2: > [ 525.037331] intel_rps_park+0x72/0x230 [i915] > [ 525.037552] __gt_park+0x61/0xa0 [i915] > [ 525.037771] ____intel_wakeref_put_last+0x42/0x90 [i915] > [ 525.037991] __intel_wakeref_put_work+0xd3/0xf0 [i915] > [ 525.038008] process_one_work+0x3b1/0x690 > [ 525.038022] worker_thread+0x80/0x670 > [ 525.038037] kthread+0x19a/0x1e0 > [ 525.038051] ret_from_fork+0x1f/0x30 > [ 525.038062] > [ 525.038074] read to 0xffff8881f145efa1 of 1 bytes by task 733 on cpu 3: > [ 525.038304] intel_rps_boost+0x67/0x1f0 [i915] > [ 525.038535] i915_request_wait+0x562/0x5d0 [i915] > [ 525.038764] i915_gem_object_wait_fence+0x81/0xa0 [i915] > [ 525.038994] i915_gem_object_wait_reservation+0x489/0x520 [i915] > [ 525.039224] i915_gem_wait_ioctl+0x167/0x2b0 [i915] > [ 525.039241] drm_ioctl_kernel+0xe4/0x120 > [ 525.039255] drm_ioctl+0x297/0x4c7 > [ 525.039269] ksys_ioctl+0x89/0xb0 > [ 525.039282] __x64_sys_ioctl+0x42/0x60 > [ 525.039296] do_syscall_64+0x6e/0x2c0 > [ 525.039311] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Signed-off-by: Chris Wilson Reviewed-by: Mika Kuoppala > --- > drivers/gpu/drm/i915/gt/intel_rps.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c > index 8794d399f5cd..506738dede16 100644 > --- a/drivers/gpu/drm/i915/gt/intel_rps.c > +++ b/drivers/gpu/drm/i915/gt/intel_rps.c > @@ -644,7 +644,7 @@ void intel_rps_mark_interactive(struct intel_rps *rps, bool interactive) > { > mutex_lock(&rps->power.mutex); > if (interactive) { > - if (!rps->power.interactive++ && rps->active) > + if (!rps->power.interactive++ && READ_ONCE(rps->active)) > rps_set_power(rps, HIGH_POWER); > } else { > GEM_BUG_ON(!rps->power.interactive); > @@ -721,11 +721,15 @@ void intel_rps_unpark(struct intel_rps *rps) > * performance, jump directly to RPe as our starting frequency. > */ > mutex_lock(&rps->lock); > - rps->active = true; > + > + WRITE_ONCE(rps->active, true); > + > freq = max(rps->cur_freq, rps->efficient_freq), > freq = clamp(freq, rps->min_freq_softlimit, rps->max_freq_softlimit); > intel_rps_set(rps, freq); > + > rps->last_adj = 0; > + > mutex_unlock(&rps->lock); > > if (INTEL_GEN(rps_to_i915(rps)) >= 6) > @@ -745,7 +749,7 @@ void intel_rps_park(struct intel_rps *rps) > if (INTEL_GEN(i915) >= 6) > rps_disable_interrupts(rps); > > - rps->active = false; > + WRITE_ONCE(rps->active, false); > if (rps->last_freq <= rps->idle_freq) > return; > > @@ -772,7 +776,7 @@ void intel_rps_boost(struct i915_request *rq) > struct intel_rps *rps = &rq->engine->gt->rps; > unsigned long flags; > > - if (i915_request_signaled(rq) || !rps->active) > + if (i915_request_signaled(rq) || !READ_ONCE(rps->active)) > return; > > /* Serializes with i915_request_retire() */ > -- > 2.20.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx