Date: Thu, 18 Sep 1997 21:41:16 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Nate Williams <nate@mt.sri.com> Cc: Graham Wheeler <gram@cdsec.com>, hackers@freebsd.org Subject: Re: Bug in malloc/free (was: Memory leak in getservbyXXX?) Message-ID: <11097.874611676@critter.freebsd.dk> In-Reply-To: Your message of "Thu, 18 Sep 1997 13:12:18 MDT." <199709181912.NAA13699@rocky.mt.sri.com>
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In message <199709181912.NAA13699@rocky.mt.sri.com>, Nate Williams writes: >[ 'hangs' in malloc due to memory over-write causing circular lists ] > >> >> This is about the only way you could get it to loop I think. That means >> >> that somebody wrote to memory malloc hadn't passed them (ie: your code). >> > >> >Yikes, this would be 'Hard to Do', even by design (ie; self-modifying >> >code). But, stranger things have happened, especially with dealing with >> >malloc/free. >> >> No, all you have to do is to make each allocation have it's own set of >> pages, munmap them when free is called and never use those pages again. >> >> You run out of address space really fast, and it is slow, but it works. > >It's slow, but how would it cause malloc to hang? It wouldn't, it would detect accesses to free'ed memory. -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop."
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