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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76A2EC4332F for ; Sat, 24 Dec 2022 01:34:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236749AbiLXBeF (ORCPT ); Fri, 23 Dec 2022 20:34:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236671AbiLXBdM (ORCPT ); Fri, 23 Dec 2022 20:33:12 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 718D640806; Fri, 23 Dec 2022 17:31:15 -0800 (PST) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 50BEB61F9C; Sat, 24 Dec 2022 01:31:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23ABCC433F0; Sat, 24 Dec 2022 01:31:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671845474; bh=IttfnRdxllbwwyrZh41FfXPVwXvCKzCGyp9jpI3PxN4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hefv+Jui/kGXe4r3z27ShHfS8OxftO/4LP22NIy+v5EWGX4pZLyt/eQLMeCgZ6TIp r3FC2jjgwH/xaoPCUNIWfDpH5g9iZIe6Ll/YCqKcY7N8dwyn7TqvafKM+zGehK/OlQ 0p3rYgnWfVPjl+CFv/+xGtAWOexI4ARDdvhrmvIdedRspdo0qj2bTj9v/WwhI2ba9C ginzu7Kc2y9UOXDdxtyod6SY7bxLEsVjaTxaK/qMnV+ebumpTOKTL7QOvfDtqjcKYL JiGOCpi3qld6UM19j0Nhz5Zcx1HfPZYFfY/wk2zmXUxpIRhX+Ke2ic6I5SKM6J6pk2 jWF97KZUFBHAw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Eli Billauer , Hyunwoo Kim , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH AUTOSEL 6.0 11/18] char: xillybus: Fix trivial bug with mutex Date: Fri, 23 Dec 2022 20:30:27 -0500 Message-Id: <20221224013034.392810-11-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221224013034.392810-1-sashal@kernel.org> References: <20221224013034.392810-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eli Billauer [ Upstream commit c002f04c0bc79ec00d4beb75fb631d5bf37419bd ] @unit_mutex protects @unit from being freed, so obviously it should be released after @unit is used, and not before. This is a follow-up to commit 282a4b71816b ("char: xillybus: Prevent use-after-free due to race condition") which ensures, among others, the protection of @private_data after @unit_mutex has been released. Reported-by: Hyunwoo Kim Signed-off-by: Eli Billauer Link: https://lore.kernel.org/r/20221117071825.3942-1-eli.billauer@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/char/xillybus/xillybus_class.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c index 0f238648dcfe..e9a288e61c15 100644 --- a/drivers/char/xillybus/xillybus_class.c +++ b/drivers/char/xillybus/xillybus_class.c @@ -227,14 +227,15 @@ int xillybus_find_inode(struct inode *inode, break; } - mutex_unlock(&unit_mutex); - - if (!unit) + if (!unit) { + mutex_unlock(&unit_mutex); return -ENODEV; + } *private_data = unit->private_data; *index = minor - unit->lowest_minor; + mutex_unlock(&unit_mutex); return 0; } EXPORT_SYMBOL(xillybus_find_inode); -- 2.35.1