Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1350314 > unrolled thread

Re: [PATCH] clk: sunxi: Remove use of VLAIS

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [PATCH] clk: sunxi: Remove use of VLAIS Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-03-04 16:30 +0100
    Re: [PATCH] clk: sunxi: Remove use of VLAIS Stephen Boyd <sboyd@codeaurora.org> - 2016-03-04 18:20 +0100
      Re: [PATCH] clk: sunxi: Remove use of VLAIS Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-03-08 23:20 +0100
        Re: [PATCH] clk: sunxi: Remove use of VLAIS Stephen Boyd <sboyd@codeaurora.org> - 2016-03-15 23:20 +0100

#1350314 — Re: [PATCH] clk: sunxi: Remove use of VLAIS

[Multipart message — attachments visible in raw view] — view raw

Hi,

On Thu, Mar 03, 2016 at 11:16:04AM -0800, Stephen Boyd wrote:
> On 03/03, Chen-Yu Tsai wrote:
> > On Tue, Mar 1, 2016 at 4:20 PM, Stephen Boyd <sboyd@codeaurora.org> wrote:
> > >         div = kzalloc(sizeof(*div), GFP_KERNEL);
> > > @@ -107,6 +111,8 @@ err_free_div:
> > >         kfree(div);
> > >  err_unmap:
> > >         iounmap(reg);
> > > +err_free_parents:
> > > +       kfree(parents);
> > 
> > AFAIK the CCF makes a deep copy of parents, so you should
> > always free it? I specifically checked it before using
> > VLAIS here.
> > 
> 
> Yes. Good catch. Here's the update.
> 
> --8<---
> From: Stephen Boyd <sboyd@codeaurora.org>
> Subject: [PATCH] clk: sunxi: Remove use of VLAIS

VLAIS?

> Using an array allocated on the stack may lead to stack overflows
> and other problems. Furthermore, VLAIS doesn't work well with
> LLVM compilers, so move the allocation to the heap and avoid the
> use of VLAIS here.
> 
> Cc: Chen-Yu Tsai <wens@csie.org>
> Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> ---
>  drivers/clk/sunxi/clk-sun8i-mbus.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/sunxi/clk-sun8i-mbus.c b/drivers/clk/sunxi/clk-sun8i-mbus.c
> index 3aaa9cbef791..90acc8549d60 100644
> --- a/drivers/clk/sunxi/clk-sun8i-mbus.c
> +++ b/drivers/clk/sunxi/clk-sun8i-mbus.c
> @@ -33,7 +33,7 @@ static DEFINE_SPINLOCK(sun8i_a23_mbus_lock);
>  static void __init sun8i_a23_mbus_setup(struct device_node *node)
>  {
>  	int num_parents = of_clk_get_parent_count(node);
> -	const char *parents[num_parents];
> +	const char **parents;
>  	const char *clk_name = node->name;
>  	struct resource res;
>  	struct clk_divider *div;
> @@ -43,10 +43,14 @@ static void __init sun8i_a23_mbus_setup(struct device_node *node)
>  	void __iomem *reg;
>  	int err;
>  
> +	parents = kcalloc(num_parents, sizeof(*parents), GFP_KERNEL);
> +	if (!parents)
> +		return;
> +
>  	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
>  	if (!reg) {
>  		pr_err("Could not get registers for sun8i-mbus-clk\n");
> -		return;
> +		goto err_free_parents;
>  	}
>  
>  	div = kzalloc(sizeof(*div), GFP_KERNEL);
> @@ -90,6 +94,7 @@ static void __init sun8i_a23_mbus_setup(struct device_node *node)
>  	if (err)
>  		goto err_unregister_clk;
>  
> +	kfree(parents); /* parents is deep copied */
>  	/* The MBUS clocks needs to be always enabled */
>  	__clk_get(clk);
>  	clk_prepare_enable(clk);
> @@ -107,6 +112,8 @@ err_free_div:
>  	kfree(div);
>  err_unmap:
>  	iounmap(reg);
> +err_free_parents:
> +	kfree(parents);
>  	of_address_to_resource(node, 0, &res);
>  	release_mem_region(res.start, resource_size(&res));

The error path is wrong here, if you jump here from a failing call to
of_io_request_and_map, you'll end up releasing a memory region which
is not requested.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[toc] | [next] | [standalone]

#1350454

On 03/04, Maxime Ripard wrote:
> On Thu, Mar 03, 2016 at 11:16:04AM -0800, Stephen Boyd wrote:
> > From: Stephen Boyd <sboyd@codeaurora.org>
> > Subject: [PATCH] clk: sunxi: Remove use of VLAIS
> 
> VLAIS?

Hmm I guess it's just VLA, so llvm won't break. I'll reword
commit text.

> 
> > @@ -107,6 +112,8 @@ err_free_div:
> >  	kfree(div);
> >  err_unmap:
> >  	iounmap(reg);
> > +err_free_parents:
> > +	kfree(parents);
> >  	of_address_to_resource(node, 0, &res);
> >  	release_mem_region(res.start, resource_size(&res));
> 
> The error path is wrong here, if you jump here from a failing call to
> of_io_request_and_map, you'll end up releasing a memory region which
> is not requested.
> 

Oh right. Let's hope third time is the last.

---8<---
From: Stephen Boyd <sboyd@codeaurora.org>
Subject: [PATCH] clk: sunxi: Remove use of variable length array

Using an array allocated on the stack may lead to stack overflows
and other problems so let's move the allocation to the heap
instead. This silences the following checker warning as well.

drivers/clk/sunxi/clk-sun8i-mbus.c:36:29: warning: Variable length array is used.

Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 drivers/clk/sunxi/clk-sun8i-mbus.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/sunxi/clk-sun8i-mbus.c b/drivers/clk/sunxi/clk-sun8i-mbus.c
index 3aaa9cbef791..411d3033a96e 100644
--- a/drivers/clk/sunxi/clk-sun8i-mbus.c
+++ b/drivers/clk/sunxi/clk-sun8i-mbus.c
@@ -33,7 +33,7 @@ static DEFINE_SPINLOCK(sun8i_a23_mbus_lock);
 static void __init sun8i_a23_mbus_setup(struct device_node *node)
 {
 	int num_parents = of_clk_get_parent_count(node);
-	const char *parents[num_parents];
+	const char **parents;
 	const char *clk_name = node->name;
 	struct resource res;
 	struct clk_divider *div;
@@ -43,10 +43,14 @@ static void __init sun8i_a23_mbus_setup(struct device_node *node)
 	void __iomem *reg;
 	int err;
 
+	parents = kcalloc(num_parents, sizeof(*parents), GFP_KERNEL);
+	if (!parents)
+		return;
+
 	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
 	if (!reg) {
 		pr_err("Could not get registers for sun8i-mbus-clk\n");
-		return;
+		goto err_free_parents;
 	}
 
 	div = kzalloc(sizeof(*div), GFP_KERNEL);
@@ -90,6 +94,7 @@ static void __init sun8i_a23_mbus_setup(struct device_node *node)
 	if (err)
 		goto err_unregister_clk;
 
+	kfree(parents); /* parents is deep copied */
 	/* The MBUS clocks needs to be always enabled */
 	__clk_get(clk);
 	clk_prepare_enable(clk);
@@ -109,5 +114,7 @@ err_unmap:
 	iounmap(reg);
 	of_address_to_resource(node, 0, &res);
 	release_mem_region(res.start, resource_size(&res));
+err_free_parents:
+	kfree(parents);
 }
 CLK_OF_DECLARE(sun8i_a23_mbus, "allwinner,sun8i-a23-mbus-clk", sun8i_a23_mbus_setup);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[toc] | [prev] | [next] | [standalone]

#1353443

[Multipart message — attachments visible in raw view] — view raw

On Fri, Mar 04, 2016 at 09:18:41AM -0800, Stephen Boyd wrote:
> On 03/04, Maxime Ripard wrote:
> > On Thu, Mar 03, 2016 at 11:16:04AM -0800, Stephen Boyd wrote:
> > > From: Stephen Boyd <sboyd@codeaurora.org>
> > > Subject: [PATCH] clk: sunxi: Remove use of VLAIS
> > 
> > VLAIS?
> 
> Hmm I guess it's just VLA, so llvm won't break. I'll reword
> commit text.
> 
> > 
> > > @@ -107,6 +112,8 @@ err_free_div:
> > >  	kfree(div);
> > >  err_unmap:
> > >  	iounmap(reg);
> > > +err_free_parents:
> > > +	kfree(parents);
> > >  	of_address_to_resource(node, 0, &res);
> > >  	release_mem_region(res.start, resource_size(&res));
> > 
> > The error path is wrong here, if you jump here from a failing call to
> > of_io_request_and_map, you'll end up releasing a memory region which
> > is not requested.
> > 
> 
> Oh right. Let's hope third time is the last.
> 
> ---8<---
> From: Stephen Boyd <sboyd@codeaurora.org>
> Subject: [PATCH] clk: sunxi: Remove use of variable length array
> 
> Using an array allocated on the stack may lead to stack overflows
> and other problems so let's move the allocation to the heap
> instead. This silences the following checker warning as well.
> 
> drivers/clk/sunxi/clk-sun8i-mbus.c:36:29: warning: Variable length array is used.
> 
> Cc: Chen-Yu Tsai <wens@csie.org>
> Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[toc] | [prev] | [next] | [standalone]

#1358296

On 03/08, Maxime Ripard wrote:
> On Fri, Mar 04, 2016 at 09:18:41AM -0800, Stephen Boyd wrote:
> > Oh right. Let's hope third time is the last.
> > 
> > ---8<---
> > From: Stephen Boyd <sboyd@codeaurora.org>
> > Subject: [PATCH] clk: sunxi: Remove use of variable length array
> > 
> > Using an array allocated on the stack may lead to stack overflows
> > and other problems so let's move the allocation to the heap
> > instead. This silences the following checker warning as well.
> > 
> > drivers/clk/sunxi/clk-sun8i-mbus.c:36:29: warning: Variable length array is used.
> > 
> > Cc: Chen-Yu Tsai <wens@csie.org>
> > Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
> > Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> 
> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> 

Applied to clk-next.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web