From patchwork Mon May 16 19:35:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 573315 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79E97C433FE for ; Mon, 16 May 2022 20:04:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346680AbiEPUEU (ORCPT ); Mon, 16 May 2022 16:04:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348275AbiEPT6c (ORCPT ); Mon, 16 May 2022 15:58:32 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 676CC496A0; Mon, 16 May 2022 12:50:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A35D8B81615; Mon, 16 May 2022 19:50:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3FB2C34115; Mon, 16 May 2022 19:50:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652730622; bh=QtSTpg4s7bW+z7cb5PjOt/RnDgPxZ0RF5p2u0Qr7maU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kl8RjbC956fYRtKzIBjeApzPxgj++7vOxAlSLlz5Z6LkvUzIS62IHey680LY81e/0 biVBxOFUjTJB+LNgIoYvNvUg0AjYi9wFWrbjap6M1PXYMpf9Tlmst3QXk+SIhfKYgE L+6RXk4RTGmSl0zfxRPGyMspAJ0X/f21vsu2moA8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christophe JAILLET , Lyude Paul , Sasha Levin Subject: [PATCH 5.15 017/102] drm/nouveau: Fix a potential theorical leak in nouveau_get_backlight_name() Date: Mon, 16 May 2022 21:35:51 +0200 Message-Id: <20220516193624.493092068@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220516193623.989270214@linuxfoundation.org> References: <20220516193623.989270214@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Christophe JAILLET [ Upstream commit ab244be47a8f111bc82496a8a20c907236e37f95 ] If successful ida_simple_get() calls are not undone when needed, some additional memory may be allocated and wasted. Here, an ID between 0 and MAX_INT is required. If this ID is >=100, it is not taken into account and is wasted. It should be released. Instead of calling ida_simple_remove(), take advantage of the 'max' parameter to require the ID not to be too big. Should it be too big, it is not allocated and don't need to be freed. While at it, use ida_alloc_xxx()/ida_free() instead to ida_simple_get()/ida_simple_remove(). The latter is deprecated and more verbose. Fixes: db1a0ae21461 ("drm/nouveau/bl: Assign different names to interfaces") Signed-off-by: Christophe JAILLET Reviewed-by: Lyude Paul [Fixed formatting warning from checkpatch] Signed-off-by: Lyude Paul Link: https://patchwork.freedesktop.org/patch/msgid/9ba85bca59df6813dc029e743a836451d5173221.1644386541.git.christophe.jaillet@wanadoo.fr Signed-off-by: Sasha Levin --- drivers/gpu/drm/nouveau/nouveau_backlight.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c b/drivers/gpu/drm/nouveau/nouveau_backlight.c index 12965a832f94..aa8ed08fe9a7 100644 --- a/drivers/gpu/drm/nouveau/nouveau_backlight.c +++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c @@ -46,8 +46,9 @@ static bool nouveau_get_backlight_name(char backlight_name[BL_NAME_SIZE], struct nouveau_backlight *bl) { - const int nb = ida_simple_get(&bl_ida, 0, 0, GFP_KERNEL); - if (nb < 0 || nb >= 100) + const int nb = ida_alloc_max(&bl_ida, 99, GFP_KERNEL); + + if (nb < 0) return false; if (nb > 0) snprintf(backlight_name, BL_NAME_SIZE, "nv_backlight%d", nb); @@ -411,7 +412,7 @@ nouveau_backlight_init(struct drm_connector *connector) nv_encoder, ops, &props); if (IS_ERR(bl->dev)) { if (bl->id >= 0) - ida_simple_remove(&bl_ida, bl->id); + ida_free(&bl_ida, bl->id); ret = PTR_ERR(bl->dev); goto fail_alloc; } @@ -439,7 +440,7 @@ nouveau_backlight_fini(struct drm_connector *connector) return; if (bl->id >= 0) - ida_simple_remove(&bl_ida, bl->id); + ida_free(&bl_ida, bl->id); backlight_device_unregister(bl->dev); nv_conn->backlight = NULL;