On 2016/6/28 14:27, Eric Dumazet wrote: > On Tue, 2016-06-28 at 08:22 +0200, Eric Dumazet wrote: > >> Follow the stack trace and add another cond_resched() where it is needed >> then ? >> >> Lot of this code was written decade ago where nobody expected a root >> user was going to try hard to crash its host ;) >> >> I did not check if the following is valid (Maybe __fib6_clean_all() is >> called with some spinlock/rwlock held) > > Well, fib6_run_gc() can call it with > spin_lock_bh(&net->ipv6.fib6_gc_lock) so this wont work. > > We need more invasive changes. > > > Hi Eric:
I debug this problem, and found that the __fib6_clean_all() would not hold the cpu more than 1 second event though there is a lot of ipv6 address to deal with, but the notifier_chian would call the ipv6 notifier several times and hold the cpu for a long time, so add cond_resched() in the addrconf_ifdown could solve the problem correctly, I think your first solution is the good way to fix this bug. Thanks Ding
