Date: Sat, 17 Oct 2009 23:28:38 -0700 From: Harsha <inpcb.harsha@gmail.com> To: "Robert N. M. Watson" <rwatson@freebsd.org> Cc: freebsd-current@freebsd.org, net@freebsd.org Subject: Re: Page fault in IFNET_WLOCK_ASSERT [if.c and pccbb.c] Message-ID: <e1b1c5880910172328s6bc0c53ctc782b9993ffbdb00@mail.gmail.com> In-Reply-To: <FE5F0845-B909-4B9B-A999-DAA7D8F4E56D@freebsd.org> References: <e1b1c5880910111226o65e0d1a9va975f4cd837271bb@mail.gmail.com> <alpine.BSF.2.00.0910112126050.48605@fledge.watson.org> <e1b1c5880910112138x1b46ff0eo39c10691a978c164@mail.gmail.com> <FE5F0845-B909-4B9B-A999-DAA7D8F4E56D@freebsd.org>
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Hi Robert, Apologies for not getting earlier. On Mon, Oct 12, 2009 at 6:46 AM, Robert N. M. Watson <rwatson@freebsd.org> wrote: > > Looks like a NULL pointer dereference, so perhaps a more traditional bug -- > could you convert ifindex_alloc_locked+0x71 to a line of code? You can do > this using kgdb on the kernel symbols file, perhaps "l > *ifindex_alloc_locked+0x71". It is the for loop in ifindex_alloc_locked() function- for (idx = 1; idx <= V_if_index; idx++) idx is a local variable, so I figured it is V_if_index is what is causing the page fault. It does look like a NULL pointer reference - I see that V_if_index comes from that vnet instance's value and uses the macro VNET_VNET_PTR() down the chain. Since the call chain is coming from a new thread cbb_event_thread, I believe that this thread's vnet context needs to be set using CURVNET_SET(). I'll try this tomorrow, but if think I'm not on the right track or want me to try something else please let me know. Many thanks, Harshahome | help
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