On Sat, Oct 17, 2009 at 11:42 PM, Julian Elischer <julian_at_elischer.org> wrote: > Harsha wrote: >> <rwatson_at_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(). > > but only if you have options VIMAGE defined. if not then CURVNET_SET() > is a NOP I do have the VIMAGE options turned on. Can someone tell me what is the right way to add the vnet context to cbb_event_thread? I tried adding context in two locations- 1. In cbb_insert() as- CURVNET_SET(TD_TO_VNET(curthread)); 2. In if_alloc() as- CURVNET_SET(TD_TO_VNET(curthread)); or as ifp = malloc(sizeof(struct ifnet), M_IFNET, M_WAITOK|M_ZERO); #ifdef VIMAGE ifp->if_vnet = curvnet; if (ifp->if_home_vnet == NULL) ifp->if_home_vnet = curvnet; CURVNET_SET(ifp->if_vnet); #endif But in all the cases I get a warning/error about unused variable 'saved_vnet' like this- cc1: warnings being treated as errors /usr/src/sys/net/if.c: In function 'if_alloc': /usr/src/sys/net/if.c:418: warning: unused variable 'saved_vnet' The backtrace is in the link I posted earlier. Thanks, HarshaReceived on Sun Oct 18 2009 - 21:26:52 UTC
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