linux-kernel - Re: [KJ] [PATCH] is_power_of

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 16 Feb 2007 16:13:55 +0100
From:	Andreas Schwab <schwab@...e.de>
To:	Richard Knutsson <ricknu-0@...dent.ltu.se>
Cc:	Vignesh Babu BM <vignesh.babu@...ro.com>,
	Kernel Janitors List <kernel-janitors@...ts.osdl.org>,
	linux-mm@...ck.org, tony.luck@...el.com,
	linux-ia64@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [KJ] [PATCH] is_power_of_2 in ia64mm

Richard Knutsson <ricknu-0@...dent.ltu.se> writes:

> Vignesh Babu BM wrote:
>> @@ -175,7 +176,7 @@ static int __init hugetlb_setup_sz(char *str)
>>  		tr_pages = 0x15557000UL;
>>   	size = memparse(str, &str);
>> -	if (*str || (size & (size-1)) || !(tr_pages & size) ||
>> +	if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
>>  		size <= PAGE_SIZE ||
>>  		size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
>>  		printk(KERN_WARNING "Invalid huge page size specified\n");
>>
>>   
> As we talked about before; is this really correct? !is_power_of_2(0) ==
> true while (0 & (0-1)) == 0.

size == 0 is also covered by the next two conditions, so the overall value
does not change.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@...e.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/