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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 54324C10F14 for ; Fri, 12 Apr 2019 18:31:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 216B0218D9 for ; Fri, 12 Apr 2019 18:31:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555093914; bh=HyBqBJLbHWUeQWX+cb/C4Wl/25IHsJuOK2Xzn81HSvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YUTxFGaq5D0DWgyT7mFCQiY8jINO07NqbHcnYFBIMu8MSS2nJtJeXt0GmZ1/c4Zka KUQKdqWVtqBu0QHqaYGGDvE4IwFJpQDFwCHhNvjZf0GMS5gJlkWtaXFo1DkkI5hp+6 jLTjGh6OQPzSPrhCFXXNz6XcAGPjP64YNqv+AAMs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726992AbfDLSbw (ORCPT ); Fri, 12 Apr 2019 14:31:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:50318 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726905AbfDLSbw (ORCPT ); Fri, 12 Apr 2019 14:31:52 -0400 Received: from mail.kernel.org (unknown [104.132.0.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8F938218CD; Fri, 12 Apr 2019 18:31:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555093912; bh=HyBqBJLbHWUeQWX+cb/C4Wl/25IHsJuOK2Xzn81HSvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QMXmOtwPTjD3kYgTbLxwvmjtmR2Oh8CWSUl52Dngr7bq+iyhKqnvaIxOIzVXhv7gL ms0+qyKR37MOnzXVeYeWvB+fShmPKMgL01WWk+/PJhMRyKyUMhzNA1v/bOjJ7YB9/h GAeJxlt3FdmcRWL0LXoXEFIfJa4Zqdnsm9Rc1zac= From: Stephen Boyd To: Michael Turquette , Stephen Boyd Cc: linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, Miquel Raynal , Jerome Brunet , Russell King , Jeffrey Hugo , Chen-Yu Tsai , Matti Vaittinen Subject: [PATCH v4 1/9] clkdev: Hold clocks_mutex while iterating clocks list Date: Fri, 12 Apr 2019 11:31:42 -0700 Message-Id: <20190412183150.102131-2-sboyd@kernel.org> X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog In-Reply-To: <20190412183150.102131-1-sboyd@kernel.org> References: <20190412183150.102131-1-sboyd@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We recently introduced a change to support devm clk lookups. That change introduced a code-path that used clk_find() without holding the 'clocks_mutex'. Unfortunately, clk_find() iterates over the 'clocks' list and so we need to prevent the list from being modified at the same time. Do this by holding the mutex and checking to make sure it's held while iterating the list. Note, we don't really care if the lookup is freed after we find it with clk_find() because we're just doing a pointer comparison, but if we did care we would need to keep holding the mutex while we dereference the clk_lookup pointer. Fixes: 3eee6c7d119c ("clkdev: add managed clkdev lookup registration") Cc: Miquel Raynal Cc: Jerome Brunet Cc: Russell King Cc: Michael Turquette Cc: Jeffrey Hugo Cc: Chen-Yu Tsai Cc: Matti Vaittinen Signed-off-by: Stephen Boyd --- I plan to take this through clk-fixes for v5.1-rc series. drivers/clk/clkdev.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c index 8c4435c53f09..6e787cc9e5b9 100644 --- a/drivers/clk/clkdev.c +++ b/drivers/clk/clkdev.c @@ -46,6 +46,8 @@ static struct clk_lookup *clk_find(const char *dev_id, const char *con_id) if (con_id) best_possible += 1; + lockdep_assert_held(&clocks_mutex); + list_for_each_entry(p, &clocks, node) { match = 0; if (p->dev_id) { @@ -402,7 +404,10 @@ void devm_clk_release_clkdev(struct device *dev, const char *con_id, struct clk_lookup *cl; int rval; + mutex_lock(&clocks_mutex); cl = clk_find(dev_id, con_id); + mutex_unlock(&clocks_mutex); + WARN_ON(!cl); rval = devres_release(dev, devm_clkdev_release, devm_clk_match_clkdev, cl); -- Sent by a computer through tubes