Re: [PATCH v2] powerpc/mpic: Fix memory leak of mpic on error paths

[Amit Machhiwal <amachhiw@linux.ibm.com>]

On 2026/09/30 11:39 PM, Jyoti Gupta wrote:
> mpic_alloc() allocates struct mpic (and optionally the protected
> sources bitmap) but does not free them when mpic_setup_error_int() or
> irq_domain_create_linear() fails, leaking the memory.
> 
> Free the bitmap and the mpic in the common error path before dropping the
> device node reference.
> 
> Fixes: 996983b75ceb ("powerpc/mpic: Search for open-pic device-tree node if NULL")
> Signed-off-by: Jyoti Gupta <jyoti@linux.ibm.com>
> ---
>  arch/powerpc/sysdev/mpic.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)

Thanks for addressing the comments from v1.

A couple of minor suggestions:

1. Changelog & Links: It is always a good practice to include a changelog below
   the "---" line detailing the changes made in this version (e.g. "v1 -> v2:
   ...") along with a link to the previous version(s) on lore.kernel.org. This
   helps reviewers and maintainers quickly track the evolution of the patch.

2. Minor nit in cleanup logic below:

> 
> diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
> index 257886ec3f70..b21a880777cc 100644
> --- a/arch/powerpc/sysdev/mpic.c
> +++ b/arch/powerpc/sysdev/mpic.c
> @@ -1389,7 +1389,7 @@ struct mpic * __init mpic_alloc(struct device_node *node,
>  		if (fsl_version >= 0x401) {
>  			ret = mpic_setup_error_int(mpic, intvec_top - 13);
>  			if (ret)
> -				return NULL;
> +				goto err_of_node_put;
>  		}
>  
>  	}
> @@ -1488,12 +1488,8 @@ struct mpic * __init mpic_alloc(struct device_node *node,
>  						 intvec_top,
>  						 &mpic_host_ops, mpic);
>  
> -	/*
> -	 * FIXME: The code leaks the MPIC object and mappings here; this
> -	 * is very unlikely to fail but it ought to be fixed anyways.
> -	 */
>  	if (mpic->irqhost == NULL)
> -		return NULL;
> +		goto err_of_node_put;
>  
>  	/* Display version */
>  	switch (greg_feature & MPIC_GREG_FEATURE_VERSION_MASK) {
> @@ -1527,6 +1523,9 @@ struct mpic * __init mpic_alloc(struct device_node *node,
>  	return mpic;
>  
>  err_of_node_put:
> +	if (mpic)
> +		bitmap_free(mpic->protected);
> +	kfree(mpic);

Both bitmap_free() and kfree() safely handle NULL pointers (and mpic is
guaranteed to be non-NULL at this label anyway), so the 'if (mpic)' check is
redundant.

Other than that, the patch looks good to me.  So, with this fixed, please feel
free to add:

Reviewed-by: Amit Machhiwal <amachhiw@linux.ibm.com>

Thanks,
Amit