linux-kernel - Re: [PATCH] Drivers: hv: mshv: Fix uninitialized variable in hv_call_map_stat

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Message-ID: <b5219734-c1c1-4d3c-953c-92b3c8c23988@linux.microsoft.com>
Date: Fri, 21 Mar 2025 09:50:26 -0700
From: Nuno Das Neves <nunodasneves@...ux.microsoft.com>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: "K. Y. Srinivasan" <kys@...rosoft.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>,
 Dexuan Cui <decui@...rosoft.com>, linux-hyperv@...r.kernel.org,
 linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] Drivers: hv: mshv: Fix uninitialized variable in
 hv_call_map_stat_page()

On 3/21/2025 7:35 AM, Dan Carpenter wrote:
> If the hv_do_hypercall() succeeds on the first iteration then "ret" is
> not initialized.  I re-arranged this code to make the loop clearer and
> to make it more clear that we return zero on the last line.
> 
> Fixes: f5288d14069b ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs")
> Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
> ---
>  drivers/hv/mshv_root_hv_call.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c
> index b72b59a5068b..a74e13a32183 100644
> --- a/drivers/hv/mshv_root_hv_call.c
> +++ b/drivers/hv/mshv_root_hv_call.c
> @@ -733,7 +733,7 @@ int hv_call_map_stat_page(enum hv_stats_object_type type,
>  	u64 status, pfn;
>  	int ret;
>  
> -	do {
> +	while (1) {
>  		local_irq_save(flags);
>  		input = *this_cpu_ptr(hyperv_pcpu_input_arg);
>  		output = *this_cpu_ptr(hyperv_pcpu_output_arg);
> @@ -756,11 +756,11 @@ int hv_call_map_stat_page(enum hv_stats_object_type type,
>  					    hv_current_partition_id, 1);
>  		if (ret)
>  			return ret;
> -	} while (!ret);
> +	}
>  
>  	*addr = page_address(pfn_to_page(pfn));
>  
> -	return ret;
> +	return 0;
>  }
>  
>  int hv_call_unmap_stat_page(enum hv_stats_object_type type,

Thanks Dan, I already sent a fixup for this:
https://lore.kernel.org/linux-hyperv/1742492693-21960-1-git-send-email-nunodasneves@linux.microsoft.com/