From patchwork Sun Apr 21 16:39:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Adri=C3=A1n_Larumbe?= X-Patchwork-Id: 13637402 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 18774C07C79 for ; Sun, 21 Apr 2024 16:40:29 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BF5AF112510; Sun, 21 Apr 2024 16:40:28 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="FHMf4LCm"; dkim-atps=neutral Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8BFA1112510 for ; Sun, 21 Apr 2024 16:40:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1713717625; bh=ukg6qw8U5Z46p/Fn0ryD5cc6wFsTS2m4KBCjmzl/FDw=; h=From:To:Cc:Subject:Date:From; b=FHMf4LCmyFf5sixIFOITfaBalimO45l0A7Outx06Sts1yx4+4MvBT2JPMxy1t/BJ0 oc2+KwLuAjRJWikNO8C9f5/H5GrNs3nz8ExTEKMj+MJ2B8usgSmIW/GhGrNn/110fc znsUyXRpHE83zjhERdl2mpfr/NmwLvN7Lbzzw5SYjedXUbvVO+TKlLOI3Dt28TjssR s4qQkOTsrZahKRFRkDryXUSLj441cAqF3Dt8EtDhfHoJ3Ce/jbofap91a576mZdDy8 5dJ1o1Swd4+4fXwECbqbkmV95oeksFSu2HulSgd2s9fScDNmKHW0a+1/hry2ByKTN8 Y41a+E3i2DgwQ== Received: from localhost.localdomain (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: alarumbe) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 4523F37804B2; Sun, 21 Apr 2024 16:40:24 +0000 (UTC) From: =?utf-8?q?Adri=C3=A1n_Larumbe?= To: Boris Brezillon , Rob Herring , Steven Price , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Zack Rusin , Dmitry Osipenko Cc: kernel@collabora.com, =?utf-8?q?Adri=C3=A1n_Larumbe?= , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org Subject: [PATCH] drm/panfrost: Fix dma_resv deadlock at drm object pin time Date: Sun, 21 Apr 2024 17:39:47 +0100 Message-ID: <20240421163951.3398622-1-adrian.larumbe@collabora.com> X-Mailer: git-send-email 2.44.0 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" When Panfrost must pin an object that is being prepared a dma-buf attachment for on behalf of another driver, the core drm gem object pinning code already takes a lock on the object's dma reservation. However, Panfrost GEM object's pinning callback would eventually try taking the lock on the same dma reservation when delegating pinning of the object onto the shmem subsystem, which led to a deadlock. This can be shown by enabling CONFIG_DEBUG_WW_MUTEX_SLOWPATH, which throws the following recursive locking situation: weston/3440 is trying to acquire lock: ffff000000e235a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: drm_gem_shmem_pin+0x34/0xb8 [drm_shmem_helper] but task is already holding lock: ffff000000e235a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: drm_gem_pin+0x2c/0x80 [drm] Fix it by assuming the object's reservation had already been locked by the time we reach panfrost_gem_pin. Cc: Thomas Zimmermann Cc: Dmitry Osipenko Cc: Boris Brezillon Cc: Steven Price Fixes: a78027847226 ("drm/gem: Acquire reservation lock in drm_gem_{pin/unpin}()") Signed-off-by: Adrián Larumbe Reviewed-by: Boris Brezillon --- drivers/gpu/drm/panfrost/panfrost_gem.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) base-commit: 04687bff66b8a4b22748aa7215d3baef0b318e5b diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c index d47b40b82b0b..6c26652d425d 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -192,7 +192,12 @@ static int panfrost_gem_pin(struct drm_gem_object *obj) if (bo->is_heap) return -EINVAL; - return drm_gem_shmem_pin(&bo->base); + /* + * Pinning can only happen in response to a prime attachment request from + * another driver, but that's already being handled by drm_gem_pin + */ + drm_WARN_ON(obj->dev, obj->import_attach); + return drm_gem_shmem_pin_locked(&bo->base); } static enum drm_gem_object_status panfrost_gem_status(struct drm_gem_object *obj)