On Thu, Jun 8, 2017 at 2:27 PM, Ben Greear <gree...@candelatech.com> wrote:
>
> As far as I can tell, the patch did not help, or at least we still reproduce
> the
> crash easily.
netlink dump is serialized by nlk->cb_mutex so I don't think that
patch makes any sense w.r.t race condition.
> (gdb) l *(fib6_walk_continue+0x76)
> 0x188c6 is in fib6_walk_continue
> (/home/greearb/git/linux-2.6/net/ipv6/ip6_fib.c:1593).
> 1588 if (fn == w->root)
> 1589 return 0;
> 1590 pn = fn->parent;
> 1591 w->node = pn;
> 1592 #ifdef CONFIG_IPV6_SUBTREES
> 1593 if (FIB6_SUBTREE(pn) == fn) {
Apparently fn->parent is NULL here for some reason, but
I don't know if that is expected or not. If a simple NULL check
is not enough here, we have to trace why it is NULL.
> 1594 WARN_ON(!(fn->fn_flags & RTN_ROOT));
> 1595 w->state = FWS_L;
> 1596 continue;
> 1597 }
> (gdb) l *(inet6_dump_fib+0x1ab)
> 0x1939b is in inet6_dump_fib
> (/home/greearb/git/linux-2.6/net/ipv6/ip6_fib.c:392).
> 387 w->skip = w->count;
> 388 } else
> 389 w->skip = 0;
> 390
> 391 res = fib6_walk_continue(w);
> 392 read_unlock_bh(&table->tb6_lock);
> 393 if (res <= 0) {
> 394 fib6_walker_unlink(net, w);
> 395 cb->args[4] = 0;
> 396 }
> (gdb)
Thanks.
