Messages in this thread | | | Date | Sun, 12 Mar 2023 22:58:18 +0200 | Subject | Re: [PATCH net] bonding: Fix warning in default_device_exit_batch() | From | Nikolay Aleksandrov <> |
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On 12/03/2023 17:21, Shigeru Yoshida wrote: > syzbot reported warning in default_device_exit_batch() like below [1]: > > WARNING: CPU: 1 PID: 56 at net/core/dev.c:10867 unregister_netdevice_many_notify+0x14cf/0x19f0 net/core/dev.c:10867 > ... > Call Trace: > <TASK> > unregister_netdevice_many net/core/dev.c:10897 [inline] > default_device_exit_batch+0x451/0x5b0 net/core/dev.c:11350 > ops_exit_list+0x125/0x170 net/core/net_namespace.c:174 > cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613 > process_one_work+0x9bf/0x1820 kernel/workqueue.c:2390 > worker_thread+0x669/0x1090 kernel/workqueue.c:2537 > kthread+0x2e8/0x3a0 kernel/kthread.c:376 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 > </TASK> > > For bond devices which also has a master device, IFF_SLAVE flag is > cleared at err_undo_flags label in bond_enslave() if it is not > ARPHRD_ETHER type. In this case, __bond_release_one() is not called > when bond_netdev_event() received NETDEV_UNREGISTER event. This > causes the above warning. > > This patch fixes this issue by setting IFF_SLAVE flag at > err_undo_flags label in bond_enslave() if the bond device has a master > device. >
The proper way is to check if the bond device had the IFF_SLAVE flag before the ether_setup() call which clears it, and restore it after.
> Fixes: 7d5cd2ce5292 ("bonding: correctly handle bonding type change on enslave failure") > Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> > Link: https://syzkaller.appspot.com/bug?id=391c7b1f6522182899efba27d891f1743e8eb3ef [1] > Reported-by: syzbot+9dfc3f3348729cc82277@syzkaller.appspotmail.com > Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> > --- > drivers/net/bonding/bond_main.c | 2 ++ > include/net/bonding.h | 5 +++++ > 2 files changed, 7 insertions(+) > > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c > index 00646aa315c3..1a8b59e1468d 100644 > --- a/drivers/net/bonding/bond_main.c > +++ b/drivers/net/bonding/bond_main.c > @@ -2291,6 +2291,8 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev, > dev_close(bond_dev); > ether_setup(bond_dev); > bond_dev->flags |= IFF_MASTER; > + if (bond_has_master(bond)) > + bond_dev->flags |= IFF_SLAVE; > bond_dev->priv_flags &= ~IFF_TX_SKB_SHARING; > } > } > diff --git a/include/net/bonding.h b/include/net/bonding.h > index ea36ab7f9e72..ed0b49501fad 100644 > --- a/include/net/bonding.h > +++ b/include/net/bonding.h > @@ -57,6 +57,11 @@ > > #define bond_has_slaves(bond) !list_empty(bond_slave_list(bond)) > > +/* master list primitives */ > +#define bond_master_list(bond) (&(bond)->dev->adj_list.upper) > + > +#define bond_has_master(bond) !list_empty(bond_master_list(bond)) > +
This is not the proper way to check for a master device.
> /* IMPORTANT: bond_first/last_slave can return NULL in case of an empty list */ > #define bond_first_slave(bond) \ > (bond_has_slaves(bond) ? \
The device flags are wrong because of ether_setup() which clears IFF_SLAVE, we should just check if it was present before and restore it after the ether_setup() call.
I'll send a fix tomorrow after testing it.
Thanks, Nik
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