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Date:      Fri, 23 Aug 2002 07:15:53 +0200
From:      Poul-Henning Kamp <phk@critter.freebsd.dk>
To:        "Un, SungKyong" <skun@etri.re.kr>
Cc:        freebsd-hackers@FreeBSD.ORG
Subject:   Re: userland malloc() and zeroed page allocation in Kernel 
Message-ID:  <16196.1030079753@critter.freebsd.dk>
In-Reply-To: Your message of "Fri, 23 Aug 2002 11:09:07 %2B0900." <001601c24a4a$121fbb60$1bf2fe81@etri.re.kr> 

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In message <001601c24a4a$121fbb60$1bf2fe81@etri.re.kr>, "Un, SungKyong" writes:

>But when I try to test this, something strange happed.
>
>    for (i=0; i<200;i++) {
>        malloc(1MB);
>        check it's all zeroed;
>        set this block to 'X';
>    }
>    free all allocated memory(200MB);
>    for (i=0; i<200;i++) {
>        malloc(1MB);
>        check it's all 'X';
>    }

You cannot trust the value of memory you have free(3)'ed to stay
until you malloc(3) again.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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