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Date: Sat, 28 Feb 2026 11:02:49 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Baoquan He <bhe@redhat.com>, Vivek Goyal <vgoyal@redhat.com>, Dave Young
 <dyoung@redhat.com>, kexec@lists.infradead.org,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH] crash_dump: Remove redundant less-than-zero check
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On Sat, 28 Feb 2026 09:51:36 +0100 Thorsten Blum <thorsten.blum@linux.dev> wrote:

> 'key_count' is an 'unsigned int' and cannot be less than zero. Remove
> the redundant condition.
> 

umm. OK.

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

iirc Linus has said "this is OK".  The compiler will eliminate it and
the code still works if the type is later changed to signed.