From patchwork Fri Jun 28 12:58:03 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13716103 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 7F561C30658 for ; Fri, 28 Jun 2024 13:06:26 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C591610EC50; Fri, 28 Jun 2024 13:06:25 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; secure) header.d=linutronix.de header.i=@linutronix.de header.b="2zYIyDci"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="+lMQ6UWs"; dkim-atps=neutral Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by gabe.freedesktop.org (Postfix) with ESMTPS id A456710EC3D; Fri, 28 Jun 2024 13:06:08 +0000 (UTC) From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1719579967; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LClj3izlGXaMQIAeLbUmdyrhrmCGtl3RogJfw1vnch0=; b=2zYIyDci8NBP/NN7DSu0YXamEIBfd+7d+Y7yCR13wPXuWQajQdxZnVnDhTrSpfDY5x56gr OH0zo1vnK/iNnJeQEy1EuQ3+HJ9vAYMAkPDRKucuNXmhgGuhBMV2zk2KtBv07ivYR05CaM nxLeX6rSqOxLtzRX1ZDpffwEs253CpdrOdYjIq99tQCHqxzUlbZSDbNKPAz8ziceKXZVbw MkdlXd/PcT9ZuWf/jdYwZrFQzfl3WYtIbMGDOJ2U6jrdASqBfTBC8VbHwS7uMLff5WEl30 RAjxb/asmFTrCO6mOPyTpJFG3T4Z6P+c5g36Y264tt6Fh2xYyQQVhO3Irkhofw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1719579967; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LClj3izlGXaMQIAeLbUmdyrhrmCGtl3RogJfw1vnch0=; b=+lMQ6UWsnbKyzEvfevQJ82gMw1Odozv/Hbzq2++Mh8tJw1WSpJ5zwDiygKa04HzOZsFloD me7/IapFbSsB4lAA== To: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Cc: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Thomas Gleixner , Tvrtko Ursulin , Sebastian Andrzej Siewior , Tvrtko Ursulin , Luca Abeni , Steven Rostedt Subject: [PATCH v3 4/8] drm/i915: Disable tracing points on PREEMPT_RT Date: Fri, 28 Jun 2024 14:58:03 +0200 Message-ID: <20240628130601.1772849-5-bigeasy@linutronix.de> In-Reply-To: <20240628130601.1772849-1-bigeasy@linutronix.de> References: <20240628130601.1772849-1-bigeasy@linutronix.de> MIME-Version: 1.0 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" Luca Abeni reported this: | BUG: scheduling while atomic: kworker/u8:2/15203/0x00000003 | CPU: 1 PID: 15203 Comm: kworker/u8:2 Not tainted 4.19.1-rt3 #10 | Call Trace: | rt_spin_lock+0x3f/0x50 | gen6_read32+0x45/0x1d0 [i915] | g4x_get_vblank_counter+0x36/0x40 [i915] | trace_event_raw_event_i915_pipe_update_start+0x7d/0xf0 [i915] The tracing events use trace_intel_pipe_update_start() among other events use functions acquire spinlock_t locks which are transformed into sleeping locks on PREEMPT_RT. A few trace points use intel_get_crtc_scanline(), others use ->get_vblank_counter() wich also might acquire a sleeping locks on PREEMPT_RT. At the time the arguments are evaluated within trace point, preemption is disabled and so the locks must not be acquired on PREEMPT_RT. Based on this I don't see any other way than disable trace points on PREMPT_RT. Acked-by: Tvrtko Ursulin Reported-by: Luca Abeni Cc: Steven Rostedt Signed-off-by: Sebastian Andrzej Siewior --- drivers/gpu/drm/i915/display/intel_display_trace.h | 4 ++++ drivers/gpu/drm/i915/i915_trace.h | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_display_trace.h b/drivers/gpu/drm/i915/display/intel_display_trace.h index 49a5e6d9dc0d7..b15c999d91e68 100644 --- a/drivers/gpu/drm/i915/display/intel_display_trace.h +++ b/drivers/gpu/drm/i915/display/intel_display_trace.h @@ -9,6 +9,10 @@ #if !defined(__INTEL_DISPLAY_TRACE_H__) || defined(TRACE_HEADER_MULTI_READ) #define __INTEL_DISPLAY_TRACE_H__ +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) +#define NOTRACE +#endif + #include #include #include diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h index ce1cbee1b39dd..247e7d9448d70 100644 --- a/drivers/gpu/drm/i915/i915_trace.h +++ b/drivers/gpu/drm/i915/i915_trace.h @@ -6,6 +6,10 @@ #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ) #define _I915_TRACE_H_ +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) +#define NOTRACE +#endif + #include #include #include