On Tue, 12 May 2020 22:47:10 +0530 Amol Grover wrote: > > > This is a strange condition, IMHO. How can we be fine with either > > > lock.. This is supposed to be the writer side lock, one can't have > > > two writer side locks.. > > > > > > I think what is happening is this: > > > > > > ipmr_net_init() -> ipmr_rules_init() -> ipmr_new_table() > > > > > > ipmr_new_table() returns an existing table if there is one, but > > > obviously none can exist at init. So a better fix would be: > > > > > > #define ipmr_for_each_table(mrt, net) > > > \ > > > list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list, \ > > > lockdep_rtnl_is_held() || \ > > > list_empty(&net->ipv4.mr_tables)) > > > > > Jakub, I agree, this condition looks better (and correct) than the one I > proposed. I'll do the changes as necessary. Also, do you want me to add > the full trace to the git commit body as well? I omitted it on purpose > to not make it messy.
In this case we can leave it at the depth of IPMR code + the caller, so: [ 1.534758] ? ipmr_get_table+0x3c/0x70 [ 1.535430] ? ipmr_new_table+0x1c/0x60 [ 1.536173] ? ipmr_net_init+0x7b/0x170 [ 1.536923] ? register_pernet_subsys+0xd/0x30 This makes it clear that the problem happens at net namespace init. Thanks!
