| Message ID | 20190703061631.84485-1-maheshb@google.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [next] loopback: fix lockdep splat | expand |
Hi Mahesh, s/lockdep/rcu/ in the subject. On Wed, Jul 3, 2019 at 8:16 AM Mahesh Bandewar <maheshb@google.com> wrote: > dev_init_scheduler() and dev_activate() expect the caller to > hold RTNL. Since we don't want blackhole device to be initialized > per ns, we are initializing at init. > > [ 3.855027] Call Trace: > [ 3.855034] dump_stack+0x67/0x95 > [ 3.855037] lockdep_rcu_suspicious+0xd5/0x110 > [ 3.855044] dev_init_scheduler+0xe3/0x120 > [ 3.855048] ? net_olddevs_init+0x60/0x60 > [ 3.855050] blackhole_netdev_init+0x45/0x6e > [ 3.855052] do_one_initcall+0x6c/0x2fa > [ 3.855058] ? rcu_read_lock_sched_held+0x8c/0xa0 > [ 3.855066] kernel_init_freeable+0x1e5/0x288 > [ 3.855071] ? rest_init+0x260/0x260 > [ 3.855074] kernel_init+0xf/0x180 > [ 3.855076] ? rest_init+0x260/0x260 > [ 3.855078] ret_from_fork+0x24/0x30 > > Fixes: 4de83b88c66 ("loopback: create blackhole net device similar to loopack.") > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > Cc: Eric Dumazet <edumazet@google.com> > Signed-off-by: Mahesh Bandewar <maheshb@google.com> Thanks, that got rid of the rcu splat. Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Gr{oetje,eeting}s, Geert
From: Mahesh Bandewar <maheshb@google.com> Date: Tue, 2 Jul 2019 23:16:31 -0700 > dev_init_scheduler() and dev_activate() expect the caller to > hold RTNL. Since we don't want blackhole device to be initialized > per ns, we are initializing at init. > > [ 3.855027] Call Trace: > [ 3.855034] dump_stack+0x67/0x95 > [ 3.855037] lockdep_rcu_suspicious+0xd5/0x110 > [ 3.855044] dev_init_scheduler+0xe3/0x120 > [ 3.855048] ? net_olddevs_init+0x60/0x60 > [ 3.855050] blackhole_netdev_init+0x45/0x6e > [ 3.855052] do_one_initcall+0x6c/0x2fa > [ 3.855058] ? rcu_read_lock_sched_held+0x8c/0xa0 > [ 3.855066] kernel_init_freeable+0x1e5/0x288 > [ 3.855071] ? rest_init+0x260/0x260 > [ 3.855074] kernel_init+0xf/0x180 > [ 3.855076] ? rest_init+0x260/0x260 > [ 3.855078] ret_from_fork+0x24/0x30 > > Fixes: 4de83b88c66 ("loopback: create blackhole net device similar to loopack.") > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > Cc: Eric Dumazet <edumazet@google.com> > Signed-off-by: Mahesh Bandewar <maheshb@google.com> Applied.
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c index 3b39def5471e..14545a8797a8 100644 --- a/drivers/net/loopback.c +++ b/drivers/net/loopback.c @@ -261,8 +261,10 @@ static int __init blackhole_netdev_init(void) if (!blackhole_netdev) return -ENOMEM; + rtnl_lock(); dev_init_scheduler(blackhole_netdev); dev_activate(blackhole_netdev); + rtnl_unlock(); blackhole_netdev->flags |= IFF_UP | IFF_RUNNING; dev_net_set(blackhole_netdev, &init_net);
dev_init_scheduler() and dev_activate() expect the caller to hold RTNL. Since we don't want blackhole device to be initialized per ns, we are initializing at init. [ 3.855027] Call Trace: [ 3.855034] dump_stack+0x67/0x95 [ 3.855037] lockdep_rcu_suspicious+0xd5/0x110 [ 3.855044] dev_init_scheduler+0xe3/0x120 [ 3.855048] ? net_olddevs_init+0x60/0x60 [ 3.855050] blackhole_netdev_init+0x45/0x6e [ 3.855052] do_one_initcall+0x6c/0x2fa [ 3.855058] ? rcu_read_lock_sched_held+0x8c/0xa0 [ 3.855066] kernel_init_freeable+0x1e5/0x288 [ 3.855071] ? rest_init+0x260/0x260 [ 3.855074] kernel_init+0xf/0x180 [ 3.855076] ? rest_init+0x260/0x260 [ 3.855078] ret_from_fork+0x24/0x30 Fixes: 4de83b88c66 ("loopback: create blackhole net device similar to loopack.") Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Mahesh Bandewar <maheshb@google.com> --- drivers/net/loopback.c | 2 ++ 1 file changed, 2 insertions(+)