Date: Mon, 02 Nov 1998 19:49:04 -0800 From: David Greenman <dg@root.com> To: "Larry S. Lile" <lile@stdio.com> Cc: hackers@FreeBSD.ORG Subject: Re: "panic: free: multiple frees" VM bug? (long) Message-ID: <199811030349.TAA09485@implode.root.com> In-Reply-To: Your message of "Mon, 02 Nov 1998 21:35:37 EST." <Pine.BSF.3.96.981102212308.17694B-100000@heathers.stdio.com>
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>I am working on a token ring driver and I cannot seem to find >out why this is happening. I contigmalloc buffers for tranmsitting >frames and then free them later when they have been transmitted. >I have to use contigmalloc in order to get buffers below the >16M mark for dma. > >Anyone see what is wrong? Should I not do this? Or have I >stumbled over a vm bug? > >It looks like a vm bug to me, but I have been wrong before. contigmalloc() isn't just a special version of malloc() that allocates contiguous pages. It's actually a special allocator that has nothing to do with malloc() and it is thus entirely incorrect to call free() with a pointer to something that was allocated by contigmalloc(). The proper way to free stuff that was allocated with contigmalloc() is with kmem_free(). contigmalloc() is poorly named and should never have been brought into the kernel that way. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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