Date: Tue, 11 Dec 2012 11:53:43 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: mdf@FreeBSD.org Cc: Garrett Cooper <yanegomi@gmail.com>, freebsd-net@FreeBSD.org, Adrian Chadd <adrian@FreeBSD.org>, FreeBSD Current <freebsd-current@FreeBSD.org> Subject: Re: "Memory modified after free" - by whom? Message-ID: <20121211075343.GT48639@FreeBSD.org> In-Reply-To: <CAMBSHm96ZEiF4mOhUyk-aDS%2BGs%2BhDsh_dMsd-WFcmZ%2BSm6Zk%2BA@mail.gmail.com> References: <CAGH67wQKUDLQmL8cnWwgzQpWAN2OhKLu0AemPNuy7EOC-i1p9g@mail.gmail.com> <CAJ-Vmo=MsSV3DhAVEP36d%2BFccHDdQz7%2By7v5xTjYKyBP0PfQoQ@mail.gmail.com> <CAMBSHm96ZEiF4mOhUyk-aDS%2BGs%2BhDsh_dMsd-WFcmZ%2BSm6Zk%2BA@mail.gmail.com>
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On Mon, Dec 10, 2012 at 03:18:45PM -0800, mdf@freebsd.org wrote: m> On Mon, Dec 10, 2012 at 3:10 PM, Adrian Chadd <adrian@freebsd.org> wrote: m> > 9216 sounds like a jumbo frame mbuf. So the NIC is writing to an mbuf m> > after it's finalised/freed. m> > m> > I have a similar bug showing up on ath(4) RX. :( m> m> Compile with DEBUG_MEMGUARD in the kernel configuration, and then set m> vm.memguard.desc to the name of the UMA zone used for the 9216 byte m> allocations, mbuf_jumbo_9k. This should cause a panic when the memory m> is touched after free. DEBUG_MEMGUARD doesn't work with cluster zone, I'm afraid it won't work with mbuf_jumbo_9k, too, but I didn't try this. The problem is documented in BUGS in memguard(9). -- Totus tuus, Glebius.
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