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 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 979BBD44D54 for ; Wed, 6 Nov 2024 12:16:49 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B03A410E6C3; Wed, 6 Nov 2024 12:16:48 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="InCqEwsK"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5993810E1EB for ; Wed, 6 Nov 2024 12:16:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1730895405; bh=YcPzdGaKdcvEymYoNrWt7jy2/at2jPjvCWmCyoiUoIc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=InCqEwsK/rdYc8sEiH41VHMK+CnMosqltxkP2dk7/XqgB2rlL2cuiLPnK9SQbgGIl DLUpGEYqTW6WUWsQrwPSUR34bj4UGsOrtwDWfZe8i00yrwu4Lt/ppUm43LXwBU5+eq QnnLZbsThQX7Kre7+pAOh7G/VhKZwvhQTelAUCBBUxsCO2zu9g415CJOtCHdb1u940 kCEJFMhjMNTESqjDZ8rFXjTHY2fd1NjS2E8YtTb0eNjzsvUW0yAWfPGC36JHdeI+jN 6Q7RHy/h0VyMcjl42leNtnN2gJXkdhEZU8CRrJOdqEz5k5vVur5d0jdqJDs1+K1Z// tGZxVEAMBSC5A== Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (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: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id 7E21E17E3617; Wed, 6 Nov 2024 13:16:45 +0100 (CET) Date: Wed, 6 Nov 2024 13:16:41 +0100 From: Boris Brezillon To: Liviu Dudau Cc: Steven Price , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Jann Horn Subject: Re: [PATCH] drm/panthor: Lock XArray when getting entries for heap and VM Message-ID: <20241106131641.47487624@collabora.com> In-Reply-To: <20241106120748.290697-1-liviu.dudau@arm.com> References: <20241106120748.290697-1-liviu.dudau@arm.com> Organization: Collabora X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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" On Wed, 6 Nov 2024 12:07:48 +0000 Liviu Dudau wrote: > Similar to cac075706f29 ("drm/panthor: Fix race when converting > group handle to group object") we need to use the XArray's internal > locking when retrieving a pointer from there for heap and vm. > > Reported-by: Jann Horn > Cc: Boris Brezillon > Cc: Steven Price > Signed-off-by: Liviu Dudau > --- > drivers/gpu/drm/panthor/panthor_heap.c | 15 +++++++++++++-- > drivers/gpu/drm/panthor/panthor_mmu.c | 2 ++ > 2 files changed, 15 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/panthor/panthor_heap.c > index 3796a9eb22af2..fe0bcb6837f74 100644 > --- a/drivers/gpu/drm/panthor/panthor_heap.c > +++ b/drivers/gpu/drm/panthor/panthor_heap.c > @@ -351,6 +351,17 @@ int panthor_heap_create(struct panthor_heap_pool *pool, > return ret; > } > > +static struct panthor_heap *panthor_heap_from_id(struct pathor_heap_pool *pool, u32 id) struct pathor_heap_pool does not exist :-). > +{ > + struct panthor_heap *heap; > + > + xa_lock(&pool->xa); > + heap = xa_load(&pool->xa, id); > + xa_unlock(&pool->va); Access to panthor_heap_pool::xa is protected by the external pathor_heap_pool::lock, so taking the xa lock seems redundant here. How about adding a lockdep_assert_held(pool->lock) instead? > + > + return heap; > +} > + > /** > * panthor_heap_return_chunk() - Return an unused heap chunk > * @pool: The pool this heap belongs to. > @@ -375,7 +386,7 @@ int panthor_heap_return_chunk(struct panthor_heap_pool *pool, > return -EINVAL; > > down_read(&pool->lock); > - heap = xa_load(&pool->xa, heap_id); > + heap = panthor_heap_from_id(pool, heap_id); > if (!heap) { > ret = -EINVAL; > goto out_unlock; > @@ -438,7 +449,7 @@ int panthor_heap_grow(struct panthor_heap_pool *pool, > return -EINVAL; > > down_read(&pool->lock); > - heap = xa_load(&pool->xa, heap_id); > + heap = panthor_heap_from_id(pool, heap_id); > if (!heap) { > ret = -EINVAL; > goto out_unlock; > diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c > index 8ca85526491e6..8b5cda9d21768 100644 > --- a/drivers/gpu/drm/panthor/panthor_mmu.c > +++ b/drivers/gpu/drm/panthor/panthor_mmu.c > @@ -1580,7 +1580,9 @@ panthor_vm_pool_get_vm(struct panthor_vm_pool *pool, u32 handle) > { > struct panthor_vm *vm; > > + xa_lock(&pool->xa); > vm = panthor_vm_get(xa_load(&pool->xa, handle)); > + xa_unlock(&pool->va); > > return vm; > }