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=-9.5 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 73BDFC433FF for ; Wed, 31 Jul 2019 02:46:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3CF2120693 for ; Wed, 31 Jul 2019 02:46:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rnp1qCHc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728027AbfGaCqA (ORCPT ); Tue, 30 Jul 2019 22:46:00 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:42514 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726908AbfGaCqA (ORCPT ); Tue, 30 Jul 2019 22:46:00 -0400 Received: by mail-pl1-f195.google.com with SMTP id ay6so29800316plb.9 for ; Tue, 30 Jul 2019 19:46:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=w5cOyOxhAUID1tCPC1X8j3Oj8XkaYtpNz6fVEgap7bY=; b=rnp1qCHcYJAwRdiabKV6cNpufFzp/A6Vxrprvi6fx4IJ8mS+WV2U6/yDr6/9+8xoY0 VF5vHB0iDUOSz1JdcfyQVrrrpjJZjDPNUt/gTa59VrBZ+1PzA2n1Ulwyz4vqPPSyJljk i/MNLD59hZ+Tl+aC1fziE60Tdsxe7YvKmO88pQaQAoNIfEgYf5iHGvOBabPbUHhQuCNo ZEkAan+pqyvT5kmtZqR+0Bnx7DMNkzsAIBBRfGmPUUTlsZyeecKeCOT+qpxj6aVXJxGc QReanCXCCqmRJV3MFvkQBMu3pgnqs+aDI0rFoLyCe3OXABJ4+W1/BBgIAI0ko56UEtxM vDWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=w5cOyOxhAUID1tCPC1X8j3Oj8XkaYtpNz6fVEgap7bY=; b=FY31TQ14u0gc4kJwbIj/VuSRo8UzooDK6lA7tHZ56dDoip0K5q5mkBXohW2GH2rKKW vO8AVtNSzy3+5dOpwWru/eLoFNjkS6bzXGA20+HtfWF5AkVQpDAmPRNRa0l/m52It9jS 8o5aJ74IiYNjWnKmsyRAXkSBmHlK+/DoydMMmwmfnCzCT/rfTFWDTg+/JW+nQSGD5SoM GWswxHWSMEjQslw66QueOa8xv1hySychSxN2VAVCGW3YIYBsDCa7j49RUHh6SbrG37rB Isuyuafdi3ztmDtcXYGlzHMiDA3aBfHa3nP5jhJsGzn3Jfu4q2bvMr7GUjrAIbDueA1l b2pg== X-Gm-Message-State: APjAAAUjaDBUgFyqlcgIrx4YTjryxfX4vnAmTpsUryBVDc/cmqhSNPnS UFemyYbGoLnnW4rrFb8x4pVDn3khfpY= X-Google-Smtp-Source: APXvYqxTJb5eodj2ckVumlL+0RDRIYaiUcKFGf7ihkxXWYXlVSjbmj8L5fzvw20rUBnlycwjnBJWyQ== X-Received: by 2002:a17:902:106:: with SMTP id 6mr120329921plb.64.1564541159865; Tue, 30 Jul 2019 19:45:59 -0700 (PDT) Received: from hfq-skylake.ipads-lab.se.sjtu.edu.cn ([202.120.40.82]) by smtp.googlemail.com with ESMTPSA id q69sm230530pjb.0.2019.07.30.19.45.54 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Jul 2019 19:45:57 -0700 (PDT) From: Fuqian Huang Cc: Maarten Lankhorst , Maxime Ripard , Sean Paul , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Fuqian Huang Subject: [PATCH] drm: use trace_printk rather than printk in drm_dbg. Date: Wed, 31 Jul 2019 10:45:33 +0800 Message-Id: <20190731024533.22264-1-huangfq.daxian@gmail.com> X-Mailer: git-send-email 2.11.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c, amdgpu_ih_process calls DRM_DEBUG which calls drm_dbg and finally calls printk. As amdgpu_ih_process is called from an interrupt handler, and interrupt handler should be short as possible. As printk may lead to bogging down the system or can even create a live lock. printk should not be used in IRQ context. Instead, trace_printk is recommended. Link: https://lwn.net/Articles/365835 Signed-off-by: Fuqian Huang --- drivers/gpu/drm/drm_print.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index a17c8a14dba4..90cded140146 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -236,7 +236,7 @@ void drm_dbg(unsigned int category, const char *format, ...) vaf.fmt = format; vaf.va = &args; - printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", + trace_printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", __builtin_return_address(0), &vaf); va_end(args); -- 2.11.0