From nobody Wed Dec 17 09:16:54 2025 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 CD684C52D6C for ; Tue, 23 Aug 2022 10:42:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356232AbiHWKln (ORCPT ); Tue, 23 Aug 2022 06:41:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354472AbiHWK16 (ORCPT ); Tue, 23 Aug 2022 06:27:58 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30FBEA405E; Tue, 23 Aug 2022 02:06:02 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 733B96158C; Tue, 23 Aug 2022 09:06:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72363C433D6; Tue, 23 Aug 2022 09:06:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661245560; bh=8NPO/RNil3EyMz/EeLQp6oCAYjcVHI/yHBSsPEKl6aE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tc0FCln69K+TnD8hJKRTi+iE/eGyrpNi0gIAILbqy1n67IXYe96LleSb3+Zv9hGl0 VCiqqpr9eEaR+8prT6vc+fCTo6XHeJx6M01pkkmCHSFZzY+tmFnB642nvBRD91Gbw+ SqqbHXH4J+grJSZx4Ks9CHJZCygOE11cM8bnKeOE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Duoming Zhou , Miquel Raynal , Sasha Levin Subject: [PATCH 4.19 117/287] mtd: sm_ftl: Fix deadlock caused by cancel_work_sync in sm_release Date: Tue, 23 Aug 2022 10:24:46 +0200 Message-Id: <20220823080104.327374824@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080100.268827165@linuxfoundation.org> References: <20220823080100.268827165@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Duoming Zhou [ Upstream commit a61528d997619a518ee8c51cf0ef0513021afaff ] There is a deadlock between sm_release and sm_cache_flush_work which is a work item. The cancel_work_sync in sm_release will not return until sm_cache_flush_work is finished. If we hold mutex_lock and use cancel_work_sync to wait the work item to finish, the work item also requires mutex_lock. As a result, the sm_release will be blocked forever. The race condition is shown below: (Thread 1) | (Thread 2) sm_release | mutex_lock(&ftl->mutex) | sm_cache_flush_work | mutex_lock(&ftl->mutex) cancel_work_sync | ... This patch moves del_timer_sync and cancel_work_sync out of mutex_lock in order to mitigate deadlock. Fixes: 7d17c02a01a1 ("mtd: Add new SmartMedia/xD FTL") Signed-off-by: Duoming Zhou Signed-off-by: Miquel Raynal Link: https://lore.kernel.org/linux-mtd/20220524044841.10517-1-duoming@zju.= edu.cn Signed-off-by: Sasha Levin --- drivers/mtd/sm_ftl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mtd/sm_ftl.c b/drivers/mtd/sm_ftl.c index f3bd86e13603..e57f7ba054bc 100644 --- a/drivers/mtd/sm_ftl.c +++ b/drivers/mtd/sm_ftl.c @@ -1091,9 +1091,9 @@ static void sm_release(struct mtd_blktrans_dev *dev) { struct sm_ftl *ftl =3D dev->priv; =20 - mutex_lock(&ftl->mutex); del_timer_sync(&ftl->timer); cancel_work_sync(&ftl->flush_work); + mutex_lock(&ftl->mutex); sm_cache_flush(ftl); mutex_unlock(&ftl->mutex); } --=20 2.35.1