Re: [PATCH v2] i3c: dw: Fix memory leak in dw_i3c_master_i3c_xfers()

[Frank Li]

On Thu, Apr 02, 2026 at 11:14:38PM +0800, Felix Gu wrote:
> The dw_i3c_master_i3c_xfers() function allocates memory for the xfer
> structure using dw_i3c_master_alloc_xfer(). If pm_runtime_resume_and_get()
> fails, the function returns without freeing the allocated xfer, resulting
> in a memory leak.
>
> Use the __free(kfree) cleanup attribute to automatically free the memory
> when the variable goes out of scope.
>
> Fixes: 62fe9d06f570 ("i3c: dw: Add power management support")
> Signed-off-by: Felix Gu <ustc.gu@xxxxxxxxx>
> ---
> Changes in v2:
> - Switch to use __free(kfree) to automatically free the memory.
> - Link to v1: https://lore.kernel.org/r/20260402-dw-i3c-2-v1-1-b530970654ec@xxxxxxxxx
> ---
>  drivers/i3c/master/dw-i3c-master.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
> index d6bdb32397fb..2e31228b3809 100644
> --- a/drivers/i3c/master/dw-i3c-master.c
> +++ b/drivers/i3c/master/dw-i3c-master.c
> @@ -7,6 +7,7 @@
>
>  #include <linux/bitfield.h>
>  #include <linux/bitops.h>
> +#include <linux/cleanup.h>
>  #include <linux/clk.h>
>  #include <linux/completion.h>
>  #include <linux/err.h>
> @@ -924,7 +925,6 @@ static int dw_i3c_master_i3c_xfers(struct i3c_dev_desc *dev,
>  	struct i3c_master_controller *m = i3c_dev_get_master(dev);
>  	struct dw_i3c_master *master = to_dw_i3c_master(m);
>  	unsigned int nrxwords = 0, ntxwords = 0;
> -	struct dw_i3c_xfer *xfer;
>  	int i, ret = 0;
>
>  	if (!i3c_nxfers)
> @@ -944,7 +944,7 @@ static int dw_i3c_master_i3c_xfers(struct i3c_dev_desc *dev,
>  	    nrxwords > master->caps.datafifodepth)
>  		return -EOPNOTSUPP;
>
> -	xfer = dw_i3c_master_alloc_xfer(master, i3c_nxfers);
> +	struct dw_i3c_xfer *xfer __free(kfree) = dw_i3c_master_alloc_xfer(master, i3c_nxfers);
>  	if (!xfer)
>  		return -ENOMEM;
>
> @@ -995,7 +995,6 @@ static int dw_i3c_master_i3c_xfers(struct i3c_dev_desc *dev,
>  	}
>
>  	ret = xfer->ret;
> -	dw_i3c_master_free_xfer(xfer);

You should mention dw_i3c_master_free_xfer() is simple wrap kfree() only
in commit message.

You'd better create following patch to remove unnessary helper function
dw_i3c_master_free_xfer() and change to other place by use cleanup.

Frank

>
>  	pm_runtime_put_autosuspend(master->dev);
>  	return ret;
>
> ---
> base-commit: bd0f139e5fc11182777b81cefc3893ea508544ec
> change-id: 20260402-dw-i3c-2-8f123def99b2
>
> Best regards,
> --
> Felix Gu <ustc.gu@xxxxxxxxx>
>