> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf Of
> Marcin Szycik
> Sent: Wednesday, October 9, 2024 8:49 PM
> To: [email protected]
> Cc: [email protected]; Paul Menzel <[email protected]>;
> Marcin Szycik <[email protected]>; Michal Swiatkowski
> <[email protected]>
> Subject: [Intel-wired-lan] [PATCH iwl-net v2] ice: Fix use after free during
> unload with ports in bridge
>
> Unloading the ice driver while switchdev port representors are added to a
> bridge can lead to kernel panic. Reproducer:
>
> modprobe ice
>
> devlink dev eswitch set $PF1_PCI mode switchdev
>
> ip link add $BR type bridge
> ip link set $BR up
>
> echo 2 > /sys/class/net/$PF1/device/sriov_numvfs
> sleep 2
>
> ip link set $PF1 master $BR
> ip link set $VF1_PR master $BR
> ip link set $VF2_PR master $BR
> ip link set $PF1 up
> ip link set $VF1_PR up
> ip link set $VF2_PR up
> ip link set $VF1 up
>
> rmmod irdma ice
>
> When unloading the driver, ice_eswitch_detach() is eventually called as part
> of VF freeing. First, it removes a port representor from xarray, then
> unregister_netdev() is called (via repr->ops.rem()), finally representor is
> deallocated. The problem comes from the bridge doing its own deinit at the
> same time. unregister_netdev() triggers a notifier chain, resulting in
> ice_eswitch_br_port_deinit() being called. It should set repr->br_port = NULL,
> but this does not happen since repr has already been removed from xarray
> and is not found. Regardless, it finishes up deallocating br_port. At this
> point,
> repr is still not freed and an fdb event can happen, in which
> ice_eswitch_br_fdb_event_work() takes repr->br_port and tries to use it,
> which causes a panic (use after free).
>
> Note that this only happens with 2 or more port representors added to the
> bridge, since with only one representor port, the bridge deinit is slightly
> different (ice_eswitch_br_port_deinit() is called via
> ice_eswitch_br_ports_flush(), not ice_eswitch_br_port_unlink()).
>
> Trace:
> Oops: general protection fault, probably for non-canonical address
> 0xf129010fd1a93284: 0000 [#1] PREEMPT SMP KASAN NOPTI
> KASAN: maybe wild-memory-access in range [0x8948287e8d499420-
> 0x8948287e8d499427]
> (...)
> Workqueue: ice_bridge_wq ice_eswitch_br_fdb_event_work [ice]
> RIP: 0010:__rht_bucket_nested+0xb4/0x180
> (...)
> Call Trace:
> (...)
> ice_eswitch_br_fdb_find+0x3fa/0x550 [ice]
> ? __pfx_ice_eswitch_br_fdb_find+0x10/0x10 [ice]
> ice_eswitch_br_fdb_event_work+0x2de/0x1e60 [ice]
> ? __schedule+0xf60/0x5210
> ? mutex_lock+0x91/0xe0
> ? __pfx_ice_eswitch_br_fdb_event_work+0x10/0x10 [ice]
> ? ice_eswitch_br_update_work+0x1f4/0x310 [ice]
> (...)
>
> A workaround is available: brctl setageing $BR 0, which stops the bridge from
> adding fdb entries altogether.
>
> Change the order of operations in ice_eswitch_detach(): move the call to
> unregister_netdev() before removing repr from xarray. This way
> repr->br_port will be correctly set to NULL in
> ice_eswitch_br_port_deinit(), preventing a panic.
>
> Fixes: fff292b47ac1 ("ice: add VF representors one by one")
> Reviewed-by: Michal Swiatkowski <[email protected]>
> Reviewed-by: Paul Menzel <[email protected]>
> Signed-off-by: Marcin Szycik <[email protected]>
> ---
> v2: Added trace excerpt
> ---
> drivers/net/ethernet/intel/ice/ice_eswitch.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
Tested-by: Sujai Buvaneswaran <[email protected]>
