Re: [PATCH iwl-net 0/6] ice: fix DCB lock ordering

[Jacob Keller <jacob.e.keller@intel.com>]

On 11/2/2026 2:50 AM, Przemek Kitszel wrote:
> Fix deadlocks and lock inversions around ice DCB configuration, between
> RTNL, pf->tc_mutex, the PF devlink lock and pf->vfs.table_lock.
> 
> RTNL becomes the outer lock of all DCB configuration paths. dcbnl ops
> and ndo_setup_tc() already run under it; patch 2 makes the LLDP MIB
> change handler and ice_dcb_rebuild() take it too, so patch 5 can drop
> the now redundant pf->tc_mutex. Patch 1 goes first, so that a dcbnl op
> does not wait out a reset, whose rebuild now needs RTNL.
> 
> Enabling DCB in switchdev tears down the devlink-rate tree, which needs
> the PF devlink lock and pf->vfs.table_lock, both taken before RTNL
> elsewhere. Patch 4 only tries them, and only when a tree is exported,
> which it tells by rate_node pointers, no longer left dangling by patch 3.
> 
> Patch 6 is an unrelated fix of the ice_init_lag() error path.
> 
> Reproducers are in the commit messages, each verified to trigger the
> lockdep or KASAN report before its fix and not after it.
> 
> Petr's "ice: fix RTNL vs auxiliary device lock inversion" [0] touches
> the same ice_setup_tc() and ice_pf_dcb_cfg() code, so one of the series
> needs a rebase. With this one applied first, his patch 2 is not needed.
> [0] https://lore.kernel.org/intel-wired-lan/20261023070258.730168-1-poros@redhat.com
> 
> 

FYI, this series did not get any reports from Sashiko, and Petr's series
did. I think that one will need to rebase on top of this for ease of
application if thats ok? I've made some notes for Tony when he gets back
next week on this.

Thanks,
Jake

> 
> Przemek Kitszel (6):
>   ice: don't wait out a reset in ice_dcbnl_devreset()
>   ice: take rtnl before tc_mutex in DCB MIB change and rebuild
>   ice: clear stale rate_node pointers in
>     ice_tear_down_devlink_rate_tree()
>   ice: don't block on locks in ice_tear_down_devlink_rate_tree()
>   ice: replace tc_mutex with RTNL
>   ice: register LAG event handler last in ice_init_lag()
> 
>  .../net/ethernet/intel/ice/devlink/devlink.h  |  2 +-
>  drivers/net/ethernet/intel/ice/ice.h          |  1 -
>  drivers/net/ethernet/intel/ice/ice_dcb_lib.h  |  1 +
>  .../net/ethernet/intel/ice/devlink/devlink.c  | 52 +++++++++++++++++--
>  drivers/net/ethernet/intel/ice/ice_dcb_lib.c  | 46 ++++++++++------
>  drivers/net/ethernet/intel/ice/ice_dcb_nl.c   | 35 ++++++-------
>  drivers/net/ethernet/intel/ice/ice_lag.c      | 15 +++---
>  drivers/net/ethernet/intel/ice/ice_main.c     |  8 ++-
>  8 files changed, 108 insertions(+), 52 deletions(-)
>