linux-kernel - Re: [PATCH v2] clk: Fix memory leak in clk

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Date:   Tue, 29 Oct 2019 16:38:13 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>
CC:     <linux-clk@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        Tero Kristo <t-kristo@...com>
Subject: Re: [PATCH v2] clk: Fix memory leak in clk_unregister()

Hi Stephen,

On 29/10/19 4:36 PM, Kishon Vijay Abraham I wrote:
> Memory allocated in alloc_clk() for 'struct clk' and
> 'const char *con_id' while invoking clk_register() is never freed
> in clk_unregister(), resulting in kmemleak showing the following
> backtrace.
> 
>   backtrace:
>     [<00000000546f5dd0>] kmem_cache_alloc+0x18c/0x270
>     [<0000000073a32862>] alloc_clk+0x30/0x70
>     [<0000000082942480>] __clk_register+0xc8/0x760
>     [<000000005c859fca>] devm_clk_register+0x54/0xb0
>     [<00000000868834a8>] 0xffff800008c60950
>     [<00000000d5a80534>] platform_drv_probe+0x50/0xa0
>     [<000000001b3889fc>] really_probe+0x108/0x348
>     [<00000000953fa60a>] driver_probe_device+0x58/0x100
>     [<0000000008acc17c>] device_driver_attach+0x6c/0x90
>     [<0000000022813df3>] __driver_attach+0x84/0xc8
>     [<00000000448d5443>] bus_for_each_dev+0x74/0xc8
>     [<00000000294aa93f>] driver_attach+0x20/0x28
>     [<00000000e5e52626>] bus_add_driver+0x148/0x1f0
>     [<000000001de21efc>] driver_register+0x60/0x110
>     [<00000000af07c068>] __platform_driver_register+0x40/0x48
>     [<0000000060fa80ee>] 0xffff800008c66020
> 
> Fix it here.
> 
> Fixes: fcb0ee6a3d331fb ("clk: Implement clk_unregister")
> Cc: Tomi Valkeinen <tomi.valkeinen@...com>
> Cc: Tero Kristo <t-kristo@...com>
> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>

Ignore the v2 of this patch. Sent this patch a bit early. Sorry for the noise.

Thanks
Kishon
> ---
>  drivers/clk/clk.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 1c677d7f7f53..ecd647258c8f 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -3835,6 +3835,7 @@ static void clk_core_evict_parent_cache(struct clk_core *core)
>  void clk_unregister(struct clk *clk)
>  {
>  	unsigned long flags;
> +	struct clk_hw *hw;
>  
>  	if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
>  		return;
> @@ -3879,6 +3880,9 @@ void clk_unregister(struct clk *clk)
>  					__func__, clk->core->name);
>  
>  	kref_put(&clk->core->ref, __clk_release);
> +	hw = clk->core->hw;
> +	free_clk(clk);
> +	hw->clk = NULL;
>  unlock:
>  	clk_prepare_unlock();
>  }
>