Re: [PATCH net-next 0/2] bonding: fix locking in bond_ab_arp_probe

[Veaceslav Falico <vfalico@redhat.com>]

On Thu, Jan 23, 2014 at 12:16:02PM +0100, Veaceslav Falico wrote:
>Hi,
>
>After the latest patches, on every call of bond_ab_arp_probe() without an
>active slave I see the following warning:

Self-NAK, there are still warnings comming out from bond_ab_arp_probe and
from other parts. Calling rtnl-needed functions on that low-level functions
wasn't the best idea...

Will send v2 to fix this warning.

>
>[    7.912314] RTNL: assertion failed at net/core/dev.c (4494)
>...
>[    7.922495]  [<ffffffff817acc6f>] dump_stack+0x51/0x72
>[    7.923714]  [<ffffffff8168795e>] netdev_master_upper_dev_get+0x6e/0x70
>[    7.924940]  [<ffffffff816a2a66>] rtnl_link_fill+0x116/0x260
>[    7.926143]  [<ffffffff817acc6f>] ? dump_stack+0x51/0x72
>[    7.927333]  [<ffffffff816a350c>] rtnl_fill_ifinfo+0x95c/0xb90
>[    7.928529]  [<ffffffff8167af2b>] ? __kmalloc_reserve+0x3b/0xa0
>[    7.929681]  [<ffffffff8167bfcf>] ? __alloc_skb+0x9f/0x1e0
>[    7.930827]  [<ffffffff816a3b64>] rtmsg_ifinfo+0x84/0x100
>[    7.931960]  [<ffffffffa00bca07>] bond_ab_arp_probe+0x1a7/0x370 [bonding]
>[    7.933133]  [<ffffffffa00bcd78>] bond_activebackup_arp_mon+0x1a8/0x2f0 [bonding]
>...
>
>It happens because in bond_ab_arp_probe() we change the flags of a slave
>without holding the RTNL lock.
>
>To fix this - remove the useless curr_active_lock, RCUify it completely and
>lock RTNL while changing the slave's flags.
>
>CC: Jay Vosburgh <fubar@us.ibm.com>
>CC: Andy Gospodarek <andy@greyhouse.net>
>CC: netdev@vger.kernel.org
>Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
>
>---
> drivers/net/bonding/bond_main.c | 22 +++++++++++-----------
> 1 file changed, 11 insertions(+), 11 deletions(-)
>