From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Russell King , Stephen Boyd , Thomas Gleixner , Michael Turquette Subject: [PATCH 3.18 087/183] clk: Really fix deadlock with mmap_sem Date: Sun, 25 Jan 2015 10:06:49 -0800 Message-Id: <20150125180813.963008758@linuxfoundation.org> In-Reply-To: <20150125180810.160428929@linuxfoundation.org> References: <20150125180810.160428929@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stephen Boyd commit 89f7e9de59bf3e3cda2e00de12c66db22675a7cf upstream. Commit 6314b6796e3c (clk: Don't hold prepare_lock across debugfs creation, 2014-09-04) forgot to update one place where we hold the prepare_lock while creating debugfs directories. This means we still have the chance of a deadlock that the commit was trying to fix. Actually fix it by moving the debugfs creation outside the prepare_lock. Reported-by: Russell King Fixes: 6314b6796e3c "clk: Don't hold prepare_lock across debugfs creation" Signed-off-by: Stephen Boyd Reviewed-by: Thomas Gleixner Signed-off-by: Michael Turquette [mturquette@linaro.org: removed lockdep_assert] Signed-off-by: Greg Kroah-Hartman --- drivers/clk/clk.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -240,7 +240,6 @@ static const struct file_operations clk_ .release = single_release, }; -/* caller must hold prepare_lock */ static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) { struct dentry *d; @@ -1944,7 +1943,6 @@ int __clk_init(struct device *dev, struc else clk->rate = 0; - clk_debug_register(clk); /* * walk the list of orphan clocks and reparent any that are children of * this clock @@ -1979,6 +1977,9 @@ int __clk_init(struct device *dev, struc out: clk_prepare_unlock(); + if (!ret) + clk_debug_register(clk); + return ret; }