| Message ID | 20200925181246.25090-1-ap420073@gmail.com |
|---|---|
| Headers | show |
| Series | net: core: fix a lockdep splat in the dev_addr_list. | expand |
From: Taehee Yoo <ap420073@gmail.com> Date: Fri, 25 Sep 2020 18:12:46 +0000 > This patchset is to avoid lockdep splat. > > When a stacked interface graph is changed, netif_addr_lock() is called > recursively and it internally calls spin_lock_nested(). > The parameter of spin_lock_nested() is 'dev->lower_level', > this is called subclass. > The problem of 'dev->lower_level' is that while 'dev->lower_level' is > being used as a subclass of spin_lock_nested(), its value can be changed. > So, spin_lock_nested() would be called recursively with the same > subclass value, the lockdep understands a deadlock. > In order to avoid this, a new variable is needed and it is going to be > used as a parameter of spin_lock_nested(). > The first and second patch is a preparation patch for the third patch. > In the third patch, the problem will be fixed. > > The first patch is to add __netdev_upper_dev_unlink(). > An existed netdev_upper_dev_unlink() is renamed to > __netdev_upper_dev_unlink(). and netdev_upper_dev_unlink() > is added as an wrapper of this function. > > The second patch is to add the netdev_nested_priv structure. > netdev_walk_all_{ upper | lower }_dev() pass both private functions > and "data" pointer to handle their own things. > At this point, the data pointer type is void *. > In order to make it easier to expand common variables and functions, > this new netdev_nested_priv structure is added. > > The third patch is to add a new variable 'nested_level' > into the net_device structure. > This variable will be used as a parameter of spin_lock_nested() of > dev->addr_list_lock. > Due to this variable, it can avoid lockdep splat. Series applied, thank you.
This patchset is to avoid lockdep splat. When a stacked interface graph is changed, netif_addr_lock() is called recursively and it internally calls spin_lock_nested(). The parameter of spin_lock_nested() is 'dev->lower_level', this is called subclass. The problem of 'dev->lower_level' is that while 'dev->lower_level' is being used as a subclass of spin_lock_nested(), its value can be changed. So, spin_lock_nested() would be called recursively with the same subclass value, the lockdep understands a deadlock. In order to avoid this, a new variable is needed and it is going to be used as a parameter of spin_lock_nested(). The first and second patch is a preparation patch for the third patch. In the third patch, the problem will be fixed. The first patch is to add __netdev_upper_dev_unlink(). An existed netdev_upper_dev_unlink() is renamed to __netdev_upper_dev_unlink(). and netdev_upper_dev_unlink() is added as an wrapper of this function. The second patch is to add the netdev_nested_priv structure. netdev_walk_all_{ upper | lower }_dev() pass both private functions and "data" pointer to handle their own things. At this point, the data pointer type is void *. In order to make it easier to expand common variables and functions, this new netdev_nested_priv structure is added. The third patch is to add a new variable 'nested_level' into the net_device structure. This variable will be used as a parameter of spin_lock_nested() of dev->addr_list_lock. Due to this variable, it can avoid lockdep splat. Taehee Yoo (3): net: core: add __netdev_upper_dev_unlink() net: core: introduce struct netdev_nested_priv for nested interface infrastructure net: core: add nested_level variable in net_device drivers/infiniband/core/cache.c | 10 +- drivers/infiniband/core/cma.c | 9 +- drivers/infiniband/core/roce_gid_mgmt.c | 9 +- drivers/infiniband/ulp/ipoib/ipoib_main.c | 9 +- drivers/net/bonding/bond_alb.c | 9 +- drivers/net/bonding/bond_main.c | 10 +- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 37 ++-- .../net/ethernet/mellanox/mlxsw/spectrum.c | 24 +-- .../ethernet/mellanox/mlxsw/spectrum_router.c | 11 +- .../mellanox/mlxsw/spectrum_switchdev.c | 10 +- drivers/net/ethernet/rocker/rocker_main.c | 9 +- drivers/net/wireless/quantenna/qtnfmac/core.c | 10 +- include/linux/netdevice.h | 68 ++++++-- net/bridge/br_arp_nd_proxy.c | 26 ++- net/bridge/br_vlan.c | 20 ++- net/core/dev.c | 164 +++++++++++++----- net/core/dev_addr_lists.c | 12 +- 17 files changed, 318 insertions(+), 129 deletions(-)