From patchwork Fri Sep 6 18:06:15 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Tvrtko Ursulin X-Patchwork-Id: 13794611 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 91796E6FE46 for ; Fri, 6 Sep 2024 18:06:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3769D10EACB; Fri, 6 Sep 2024 18:06:32 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.b="GEVHNJJY"; dkim-atps=neutral Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0D03110EAC1; Fri, 6 Sep 2024 18:06:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References: In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=LbRKQC2natDUa9uyMFRK4EkFcMdJKzCTr7qA14B0ZsM=; b=GEVHNJJY0gMk64Jjm2g93r+ABL xQW0QLOZUhxkSsVtr7zqVOLz+gUZGJG5K78vSFiC4oFCuXXxST1xDpv5sAtRmekoSHmDPP6PoKyza 0N8xfv2B/6G+UtgVdWgFt6W7hJL3HMu5FOb+j87l3FWv3rQd/z8leHjd3NWVOXJKb2mAm64LFORjp UlAVRoDuiPL63SgXcHoTz75nyNHmkE/OAWfbPAeYlQ8/BP0e467f3KiToYJSI7PnEjSKNwkB9JawR i/kgZYoVWUMrGv8/ero7/NIDV3+ski88WrffR6tvCECmZeUoeZYp7+LJ5pydArdVb3JKtVf+daSz1 dS9kJaPw==; Received: from [90.241.98.187] (helo=localhost) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1smdLl-00AW6J-2R; Fri, 06 Sep 2024 20:06:24 +0200 From: Tvrtko Ursulin To: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Cc: Tvrtko Ursulin , =?utf-8?q?Christian_K=C3=B6n?= =?utf-8?q?ig?= , Alex Deucher , Luben Tuikov , Matthew Brost , David Airlie , Daniel Vetter , stable@vger.kernel.org Subject: [RFC 1/4] drm/sched: Add locking to drm_sched_entity_modify_sched Date: Fri, 6 Sep 2024 19:06:15 +0100 Message-ID: <20240906180618.12180-2-tursulin@igalia.com> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240906180618.12180-1-tursulin@igalia.com> References: <20240906180618.12180-1-tursulin@igalia.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Tvrtko Ursulin Without the locking amdgpu currently can race amdgpu_ctx_set_entity_priority() and drm_sched_job_arm(), leading to the latter accesing potentially inconsitent entity->sched_list and entity->num_sched_list pair. The comment on drm_sched_entity_modify_sched() however says: """ * Note that this must be called under the same common lock for @entity as * drm_sched_job_arm() and drm_sched_entity_push_job(), or the driver needs to * guarantee through some other means that this is never called while new jobs * can be pushed to @entity. """ It is unclear if that is referring to this race or something else. Signed-off-by: Tvrtko Ursulin Fixes: b37aced31eb0 ("drm/scheduler: implement a function to modify sched list") Cc: Christian König Cc: Alex Deucher Cc: Luben Tuikov Cc: Matthew Brost Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Cc: # v5.7+ --- drivers/gpu/drm/scheduler/sched_entity.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index 58c8161289fe..ae8be30472cd 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -133,8 +133,10 @@ void drm_sched_entity_modify_sched(struct drm_sched_entity *entity, { WARN_ON(!num_sched_list || !sched_list); + spin_lock(&entity->rq_lock); entity->sched_list = sched_list; entity->num_sched_list = num_sched_list; + spin_unlock(&entity->rq_lock); } EXPORT_SYMBOL(drm_sched_entity_modify_sched);