Re: Memory modified after free - Jan20 -CURRENT

http://bmilekic.unixdaemons.com/MemGuard.diff

put options DEBUG_MEMGUARD in your kernel config, and look at the
DEBUG_MEMGUARD ifdefs in malloc(), free(), and realloc() inside
kern/kern_malloc.c; the short of it is that you'll have to manually
modify those ifdef'd portions of code referring to M_SUBPROC in the
diff to M_WHATEVER.  I'm going to commit a version of this soon.

Don't run the patch unless you know what you're doing.

Later,
Bosko.

On Thu, Jan 20, 2005 at 12:29:27PM -0700, Scott Long wrote:
> Ketrien I. Saihr-Kenchedra wrote:
> 
> >Screen transcription attached. In a nutshell;
> >
> >fdc0: <floppy drive controller> port 0x3f7,0x3f0-0x3f5 irq 6 drq 2 on acpi0
> >device_attach: fdc0 returned 6
> >sio0: <16550A-compatible COM port> port0x3f8-0x3ff irq 4 flags 0x10 on 
> >acpi0
> >sio0: type 16550A
> >Memory modified after free 0xc1cde200(252) val=0 _at_ 0xc1cde228
> >panic: Most recently used by none
> >
> >System was fine with Jan16 srcs, fdc returning 6 is new. Looks like a uma
> >problem to me, but odd enough that I'm honestly not sure. Need ips(4) for
> >dumpdev, so no dump again. (Argh.)
> >
> 
> I'm seeing this quite often too.  I'm hoping that Bosko will make his
> memguard changes available soon as I'm sure it could quickly be tracked
> down with them.
> 
> Scott
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-- 
Bosko Milekic
bmilekic_at_technokratis.com
bmilekic_at_FreeBSD.org