linux-kernel - Re: [PATCH] dm-crypt: remove ineffective comparison

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Message-ID: <aN0hqT/iTAWodgXJ@MiWiFi-R3L-srv>
Date: Wed, 1 Oct 2025 20:42:17 +0800
From: Baoquan He <bhe@...hat.com>
To: Suchit Karunakaran <suchitkarunakaran@...il.com>, coxu@...hat.com
Cc: akpm@...ux-foundation.org, vgoyal@...hat.com, dyoung@...hat.com,
	kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
	skhan@...uxfoundation.org
Subject: Re: [PATCH] dm-crypt: remove ineffective comparison

CC Coiby,

On 10/01/25 at 05:32pm, Suchit Karunakaran wrote:
> In restore_dm_crypt_keys_to_thread_keyring(), key_count is a global
> variable declared as unsigned int. The comparison key_count < 0
> is therefore always false and has no effect.
> Remove the dead comparison to make the code clearer and
> silence static analysis warnings.
> 
> Found by Coverity: CID#1649028
> 
> Signed-off-by: Suchit Karunakaran <suchitkarunakaran@...il.com>
> ---
>  kernel/crash_dump_dm_crypt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c
> index 401423ba477d..39cfc13ff350 100644
> --- a/kernel/crash_dump_dm_crypt.c
> +++ b/kernel/crash_dump_dm_crypt.c
> @@ -115,7 +115,7 @@ static int restore_dm_crypt_keys_to_thread_keyring(void)
>  
>  	addr = dm_crypt_keys_addr;
>  	dm_crypt_keys_read((char *)&key_count, sizeof(key_count), &addr);
> -	if (key_count < 0 || key_count > KEY_NUM_MAX) {
> +	if (key_count > KEY_NUM_MAX) {

Sounds reasonable to me,

Acked-by: Baoquan He <bhe@...hat.com>

>  		kexec_dprintk("Failed to read the number of dm-crypt keys\n");
>  		return -1;
>  	}
> -- 
> 2.51.0
>