Date: Mon, 17 Aug 1998 22:33:53 +0000 From: Mike Smith <mike@smith.net.au> To: Thomas Dean <tomdean@ix.netcom.com> Cc: current@FreeBSD.ORG Subject: Re: Calloc or VM Problem Message-ID: <199808172233.WAA12072@dingo.cdrom.com> In-Reply-To: Your message of "Mon, 17 Aug 1998 22:20:56 MST." <199808180520.WAA00323@ix.netcom.com>
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Sounds like you've accidentally freed the list header at some point.
> I noted some previous problems with calloc, and, thought they were
> fixed. However, I seem to have a problem with calloc or vm.
>
> It appears that calloc is stomping on a structure. I collected some
> numbers on calloc operations. After poking with gdb for a long time,
> I found that some of the structure entries were changing around the
> calloc statement. It always changed the same section of the
> structure. I added some fixed value checks just to catch this
> problem. The "frame changed" message was always the line after the
> calloc. I changed calloc to malloc and the problem is the same.
>
> The process allocated a total of 1813088 bytes in 3713 operations.
>
> ==========================================================================
> Here is the code fragment about the problem: (I xxxx'ed some names)
>
> listPtr = xxxxHeader->xxxxEntry;
>
> while(listPtr->entry != NULL) {
> listPtr = listPtr->next;
> }
>
> if (xxxxHeader->xxxxx.len != 653) {
> print("frame changed to %d at line %d\n",
> xxxxHeader->xxxxx.len, __LINE__);
> }
>
> listPtr->entry= (Entry_t *) calloc((numEntries+1),sizeof(Entry_t));
>
> if (xxxxHeader->xxxxx.len != 653) {
> print("frame changed to %d at line %d\n",
> xxxxHeader->xxxxx.len, __LINE__);
> }
>
> ==========================================================================
> # uname -a
> FreeBSD celebris 3.0-CURRENT FreeBSD 3.0-CURRENT #1: Sat Aug 8 06:36:42 PDT1998
>
> ==========================================================================
> # dmesg <snipped>
> Copyright (c) 1982, 1986, 1989, 1991, 1993
> The Regents of the University of California. All rights reserved.
> FreeBSD 3.0-CURRENT #1: Sat Aug 8 06:36:42 PDT 1998
> root@celebris:/usr/src/sys/compile/CELEBRIS-SMP
> Timecounter "i8254" frequency 1193182 Hz cost 2540 ns
> CPU: Pentium/P54C (586-class CPU)
> Origin = "GenuineIntel" Id = 0x525 Stepping=5
> Features=0x3bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,APIC>
> real memory = 100663296 (98304K bytes)
> avail memory = 95268864 (93036K bytes)
> FreeBSD/SMP: Multiprocessor motherboard
> cpu0 (BSP): apic id: 0, version: 0x00030010, at 0xfee00000
> cpu1 (AP): apic id: 1, version: 0x00030010, at 0xfee00000
> io0 (APIC): apic id: 2, version: 0x000f0011, at 0xfec00000
> Probing for devices on PCI bus 0:
> chip0: <Intel 82434NX (Neptune) PCI cache memory controller>rev0x11on pci0.0.0
>
>
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>
--
\\ Sometimes you're ahead, \\ Mike Smith
\\ sometimes you're behind. \\ mike@smith.net.au
\\ The race is long, and in the \\ msmith@freebsd.org
\\ end it's only with yourself. \\ msmith@cdrom.com
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