From patchwork Wed Apr 8 10:48:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11479769 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F32ED92C for ; Wed, 8 Apr 2020 10:48:28 +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 DC01E20747 for ; Wed, 8 Apr 2020 10:48:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC01E20747 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk 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 713DE6EA28; Wed, 8 Apr 2020 10:48:26 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 529156EA20 for ; Wed, 8 Apr 2020 10:48:19 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from build.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 20837629-1500050 for ; Wed, 08 Apr 2020 11:48:12 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Wed, 8 Apr 2020 11:48:05 +0100 Message-Id: <20200408104812.22386-2-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200408104812.22386-1-chris@chris-wilson.co.uk> References: <20200408104812.22386-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [CI 2/9] drm/i915/gt: Mark up racy check of breadcrumb irq enabled 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" We control b->irq_enabled inside the b->irq_lock, but we check before entering the spinlock whether or not the interrupt is currently unmasked. [ 1511.735208] BUG: KCSAN: data-race in __intel_breadcrumbs_disarm_irq [i915] / intel_engine_disarm_breadcrumbs [i915] [ 1511.735231] [ 1511.735242] write to 0xffff8881f75fc214 of 1 bytes by interrupt on cpu 2: [ 1511.735440] __intel_breadcrumbs_disarm_irq+0x4b/0x160 [i915] [ 1511.735635] signal_irq_work+0x337/0x710 [i915] [ 1511.735652] irq_work_run_list+0xd7/0x110 [ 1511.735666] irq_work_run+0x1d/0x50 [ 1511.735681] smp_irq_work_interrupt+0x21/0x30 [ 1511.735701] irq_work_interrupt+0xf/0x20 [ 1511.735722] __do_softirq+0x6f/0x206 [ 1511.735736] irq_exit+0xcd/0xe0 [ 1511.735756] do_IRQ+0x44/0xc0 [ 1511.735773] ret_from_intr+0x0/0x1c [ 1511.735787] schedule+0x0/0xb0 [ 1511.735803] worker_thread+0x194/0x670 [ 1511.735823] kthread+0x19a/0x1e0 [ 1511.735837] ret_from_fork+0x1f/0x30 [ 1511.735848] [ 1511.735867] read to 0xffff8881f75fc214 of 1 bytes by task 432 on cpu 1: [ 1511.736068] intel_engine_disarm_breadcrumbs+0x22/0x80 [i915] [ 1511.736263] __engine_park+0x107/0x5d0 [i915] [ 1511.736453] ____intel_wakeref_put_last+0x44/0x90 [i915] [ 1511.736648] __intel_wakeref_put_last+0x5a/0x70 [i915] [ 1511.736842] intel_context_exit_engine+0xf2/0x100 [i915] [ 1511.737044] i915_request_retire+0x6b2/0x770 [i915] [ 1511.737244] retire_requests+0x7a/0xd0 [i915] [ 1511.737438] intel_gt_retire_requests_timeout+0x3a7/0x6f0 [i915] [ 1511.737633] i915_drop_caches_set+0x1e7/0x260 [i915] [ 1511.737650] simple_attr_write+0xfa/0x110 [ 1511.737665] full_proxy_write+0x94/0xc0 [ 1511.737679] __vfs_write+0x4b/0x90 [ 1511.737697] vfs_write+0xfc/0x280 [ 1511.737718] ksys_write+0x78/0x100 [ 1511.737732] __x64_sys_write+0x44/0x60 [ 1511.737751] do_syscall_64+0x6e/0x2c0 [ 1511.737769] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: Chris Wilson Cc: Mika Kuoppala --- drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c index cbad7fe722ce..cbedba857d43 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c @@ -64,7 +64,7 @@ static void __intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b) if (!--b->irq_enabled) irq_disable(engine); - b->irq_armed = false; + WRITE_ONCE(b->irq_armed, false); intel_gt_pm_put_async(engine->gt); } @@ -73,7 +73,7 @@ void intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine) struct intel_breadcrumbs *b = &engine->breadcrumbs; unsigned long flags; - if (!b->irq_armed) + if (!READ_ONCE(b->irq_armed)) return; spin_lock_irqsave(&b->irq_lock, flags); @@ -233,7 +233,7 @@ static bool __intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b) * which we can add a new waiter and avoid the cost of re-enabling * the irq. */ - b->irq_armed = true; + WRITE_ONCE(b->irq_armed, true); /* * Since we are waiting on a request, the GPU should be busy