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 X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2ECBFC43603 for ; Wed, 18 Dec 2019 13:41:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F051021582 for ; Wed, 18 Dec 2019 13:41:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="s2SA3jxI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727066AbfLRNl5 (ORCPT ); Wed, 18 Dec 2019 08:41:57 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:35036 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726749AbfLRNl5 (ORCPT ); Wed, 18 Dec 2019 08:41:57 -0500 Received: by mail-pj1-f66.google.com with SMTP id s7so907085pjc.0 for ; Wed, 18 Dec 2019 05:41:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=uV9emrToibtOtd5PwV/QEFcEzg9NL+MgjlxJNDfEwL8=; b=s2SA3jxImiV1cJdYXeJ5bMdJNOkWPu00GBypmHd+2bfmFA/bgWsvqXqKcn6CC7OCt4 bQi3pH7Qd2vOqWCA8SSZGIzNruFEV3mkROQNkskNLD6DsCGnvqu9JVJuX4kBmPNnCLR1 ZLwzdoXh4dgj2aA0gOe5KTznA6hhDSIazy2F3DmyYDgOrB3S764Q5PQQdrZ5GJb8xh0U 9wXBXJuo7RYu0luX2hLHqPsjgCXCrPu09hnykK6jQJIK+IWSOxMvvbTe2DnqJbWM2Ev0 9HJqQh/IzkqO08i8du0rIgbYsI0VR5yDuDeVF7YtqVLsDV6mGrgtuHdX7VoEslbkRUkT PESQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=uV9emrToibtOtd5PwV/QEFcEzg9NL+MgjlxJNDfEwL8=; b=HvjRUZotJRVqF3RdP9kKy1tL3b21VfhXx0YbpD4sYhUwByoIeDu1CIXqIKZ/yB4LD9 Mp9c5ab9Klm/eAHbUX3PMwuWdQ+RvWMgFQ0NxnkfwWU5PDJy7MMFnV1srV2YExMJT694 R/TwbkTAQE31t25HLcQTN5H9bmV9Wuqo+HaAxFtoEq520brWtJAeDgfQpB8mUwSifRuw fckHbYwOHkh/av5ZwjzrCR4rQmsPhY848um4JUO9jrKaac1TO363xdYMkmahr5FkSxlo Ga9MoSl/yDnzl/1Mf/BBE+cpkkQF1aAwxkP8xZJFjtJOfTK5hPqFWkMDXoQj0fDchZ9g VMag== X-Gm-Message-State: APjAAAUm1ZBl1wmCMdLS/sfvRXe9E0gOXHaeozodZt0nciIGBRW4TKz/ La5gn7lDFnBUX8MxdmNcPNZ58TgupNA7qw== X-Google-Smtp-Source: APXvYqylPKSnWPJojqWBvbGZ8mrsyp/IhNnFJFkXhrv8y3TDQkj5gq67R6dz66q7+bg7y4Fk/ImB3g== X-Received: by 2002:a17:902:a516:: with SMTP id s22mr2836320plq.89.1576676517024; Wed, 18 Dec 2019 05:41:57 -0800 (PST) Received: from oslab.tsinghua.edu.cn ([166.111.139.172]) by smtp.gmail.com with ESMTPSA id j3sm3323868pfi.8.2019.12.18.05.41.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Dec 2019 05:41:56 -0800 (PST) From: Jia-Ju Bai To: miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] mtd: maps: pcmciamtd: fix possible sleep-in-atomic-context bugs in pcmciamtd_set_vpp() Date: Wed, 18 Dec 2019 21:41:46 +0800 Message-Id: <20191218134146.10803-1-baijiaju1990@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The driver may sleep while holding a spinlock. The function call path (from bottom to top) in Linux 4.19 is: drivers/pcmcia/pcmcia_resource.c, 312: mutex_lock in pcmcia_fixup_vpp drivers/mtd/maps/pcmciamtd.c, 309: pcmcia_fixup_vpp in pcmciamtd_set_vpp drivers/mtd/maps/pcmciamtd.c, 306: _raw_spin_lock_irqsave in pcmciamtd_set_vpp drivers/pcmcia/pcmcia_resource.c, 312: mutex_lock in pcmcia_fixup_vpp drivers/mtd/maps/pcmciamtd.c, 312: pcmcia_fixup_vpp in pcmciamtd_set_vpp drivers/mtd/maps/pcmciamtd.c, 306: _raw_spin_lock_irqsave in pcmciamtd_set_vp mutex_lock() may sleep at runtime. To fix these bugs, pcmcia_fixup_vpp() is called without holding the spinlock. These bugs are found by a static analysis tool STCheck written by myself. Signed-off-by: Jia-Ju Bai --- drivers/mtd/maps/pcmciamtd.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/maps/pcmciamtd.c b/drivers/mtd/maps/pcmciamtd.c index 70bb403f69f7..d2cd1708aa49 100644 --- a/drivers/mtd/maps/pcmciamtd.c +++ b/drivers/mtd/maps/pcmciamtd.c @@ -301,17 +301,23 @@ static void pcmciamtd_set_vpp(struct map_info *map, int on) struct pcmciamtd_dev *dev = (struct pcmciamtd_dev *)map->map_priv_1; struct pcmcia_device *link = dev->p_dev; unsigned long flags; + int fixup_flag = 0; pr_debug("dev = %p on = %d vpp = %d\n\n", dev, on, dev->vpp); spin_lock_irqsave(&pcmcia_vpp_lock, flags); if (on) { if (++pcmcia_vpp_refcnt == 1) /* first nested 'on' */ - pcmcia_fixup_vpp(link, dev->vpp); + fixup_flag = 1; } else { if (--pcmcia_vpp_refcnt == 0) /* last nested 'off' */ - pcmcia_fixup_vpp(link, 0); + fixup_flag = 2; } spin_unlock_irqrestore(&pcmcia_vpp_lock, flags); + + if (fixup_flag == 1) + pcmcia_fixup_vpp(link, dev->vpp); + else if (fixup_flag == 2) + pcmcia_fixup_vpp(link, 0); } -- 2.17.1