linux-kernel - [PATCH AUTOSEL 4.19 02/26] clk: ti: clkctrl: Fix returning uninitialized data

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Date:   Tue,  2 Jul 2019 22:16:01 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Tony Lindgren <tony@...mide.com>,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        Peter Ujfalusi <peter.ujfalusi@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        Sasha Levin <sashal@...nel.org>, linux-omap@...r.kernel.org,
        linux-clk@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 02/26] clk: ti: clkctrl: Fix returning uninitialized data

From: Tony Lindgren <tony@...mide.com>

[ Upstream commit 41b3588dba6ef4b7995735a97e47ff0aeea6c276 ]

If we do a clk_get() for a clock that does not exists, we have
_ti_omap4_clkctrl_xlate() return uninitialized data if no match
is found. This can be seen in some cases with SLAB_DEBUG enabled:

Unable to handle kernel paging request at virtual address 5a5a5a5a
...
clk_hw_create_clk.part.33
sysc_notifier_call
notifier_call_chain
blocking_notifier_call_chain
device_add

Let's fix this by setting a found flag only when we find a match.

Reported-by: Tomi Valkeinen <tomi.valkeinen@...com>
Fixes: 88a172526c32 ("clk: ti: add support for clkctrl clocks")
Signed-off-by: Tony Lindgren <tony@...mide.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@...com>
Tested-by: Tomi Valkeinen <tomi.valkeinen@...com>
Signed-off-by: Stephen Boyd <sboyd@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/clk/ti/clkctrl.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/ti/clkctrl.c b/drivers/clk/ti/clkctrl.c
index ca3218337fd7..dfaa5aad0692 100644
--- a/drivers/clk/ti/clkctrl.c
+++ b/drivers/clk/ti/clkctrl.c
@@ -229,6 +229,7 @@ static struct clk_hw *_ti_omap4_clkctrl_xlate(struct of_phandle_args *clkspec,
 {
 	struct omap_clkctrl_provider *provider = data;
 	struct omap_clkctrl_clk *entry;
+	bool found = false;
 
 	if (clkspec->args_count != 2)
 		return ERR_PTR(-EINVAL);
@@ -238,11 +239,13 @@ static struct clk_hw *_ti_omap4_clkctrl_xlate(struct of_phandle_args *clkspec,
 
 	list_for_each_entry(entry, &provider->clocks, node) {
 		if (entry->reg_offset == clkspec->args[0] &&
-		    entry->bit_offset == clkspec->args[1])
+		    entry->bit_offset == clkspec->args[1]) {
+			found = true;
 			break;
+		}
 	}
 
-	if (!entry)
+	if (!found)
 		return ERR_PTR(-EINVAL);
 
 	return entry->clk;
-- 
2.20.1