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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B0E0EC2D0A8 for ; Wed, 23 Sep 2020 09:05:07 +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 4C3A32075B for ; Wed, 23 Sep 2020 09:05:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C3A32075B 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 7D86E6E145; Wed, 23 Sep 2020 09:05:06 +0000 (UTC) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id 34A806E145 for ; Wed, 23 Sep 2020 09:05:05 +0000 (UTC) IronPort-SDR: V3wUqs1Ct3Dl7YncECfa5uBOJi6JUORy3hPVk7b84+E6CI/gkbNOt/9jWq0qCHIv71estUIRrO WD7loykWjGnA== X-IronPort-AV: E=McAfee;i="6000,8403,9752"; a="178903659" X-IronPort-AV: E=Sophos;i="5.77,293,1596524400"; d="scan'208";a="178903659" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2020 02:04:47 -0700 IronPort-SDR: lwUXVT52PJTdkK520GPJcdg6a9It16VWhoaBTnEKofCKvjUQWDja88G4xC1+uSBKsCewsYZE7y WCOMp34+IMHg== X-IronPort-AV: E=Sophos;i="5.77,293,1596524400"; d="scan'208";a="309832346" Received: from bravinar-mobl1.ger.corp.intel.com (HELO localhost) ([10.252.9.250]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2020 02:04:45 -0700 From: Jani Nikula To: Chris Wilson , Steve Hampson , intel-gfx@lists.freedesktop.org In-Reply-To: <160085149249.27151.12750028761264321987@build.alporthouse.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20200923044054.5653-1-steven.t.hampson@intel.com> <160085149249.27151.12750028761264321987@build.alporthouse.com> Date: Wed, 23 Sep 2020 12:04:58 +0300 Message-ID: <87eemsrhhh.fsf@intel.com> MIME-Version: 1.0 Subject: Re: [Intel-gfx] [PATCH] Fix NULL pointer found by static analysis 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" On Wed, 23 Sep 2020, Chris Wilson wrote: > Quoting Steve Hampson (2020-09-23 05:40:54) >> A static analysis tool has reveiled a NULL pointer error in >> __i915_gem_object_lock. This appears to be correct as many calls >> pass a NULL into the ww parameter. >> >> Signed-off-by: Steve Hampson >> --- >> drivers/gpu/drm/i915/gem/i915_gem_object.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h >> index d46db8d8f38e..9b18ead42991 100644 >> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h >> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h >> @@ -126,7 +126,7 @@ static inline int __i915_gem_object_lock(struct drm_i915_gem_object *obj, >> if (ret == -EALREADY) >> ret = 0; >> >> - if (ret == -EDEADLK) >> + if (ret == -EDEADLK && ww) > > EDEADLK is predicated by ww already. The hard part is that neither the analyzer nor a human who doesn't know how dma_resv_lock* work can easily deduce that. :( BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx