Re: [PATCH v2 2/2] ice: clear Flow Director entries before reset cleanup

[Simon Horman <horms@kernel.org>]

On Mon, Sep 07, 2026 at 07:52:21PM +0800, Aaron Ma wrote:
> Flow Director profiles retain handles to generic flow entries. Reset calls
> ice_clear_hw_tbls() to free those entries, but leaves the Flow Director
> handles unchanged until replay replaces them.
> 
> If rebuild fails before replay completes, later driver removal follows a
> stale handle and dereferences a freed flow entry in ice_flow_rem_entry().
> KASAN reports a wild access to list poison from
> ice_fdir_erase_flow_from_hw().
> 
> The failure is reported as:
> 
>   KASAN: maybe wild-memory-access in range [0xdead000000000108-...]
>   RIP: ice_flow_rem_entry+0xaf/0x170 [ice]
>   ice_fdir_erase_flow_from_hw+0x1ee/0x420 [ice]
> 
> Clear the Flow Director handles while holding hw->fdir_fltr_lock before
> the hardware tables free their entries. A successful replay installs new
> handles, while a failed rebuild leaves them invalid for later cleanup.
> 
> Fixes: 148beb612031 ("ice: Initialize Flow Director resources")
> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
> ---
> v1 -> v2:
> - Acquire hw->fdir_fltr_lock in ice_fdir_clear_flow_handles() to
>   synchronize with concurrent ethtool filter add/del.

Reviewed-by: Simon Horman <horms@kernel.org>