RE: [Intel-wired-lan] [PATCH iwl-net v2 4/6] ice: check ICE_VSI_DOWN under rtnl_lock when preparing for reset

[Rout, ChandanX]

>-----Original Message-----
>From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of
>Zaremba, Larysa
>Sent: Wednesday, July 24, 2024 10:19 PM
>To: intel-wired-lan@xxxxxxxxxxxxxxxx
>Cc: Drewek, Wojciech <wojciech.drewek@xxxxxxxxx>; Fijalkowski, Maciej
><maciej.fijalkowski@xxxxxxxxx>; Jesper Dangaard Brouer <hawk@xxxxxxxxxx>;
>Daniel Borkmann <daniel@xxxxxxxxxxxxx>; Zaremba, Larysa
><larysa.zaremba@xxxxxxxxx>; netdev@xxxxxxxxxxxxxxx; John Fastabend
><john.fastabend@xxxxxxxxx>; Alexei Starovoitov <ast@xxxxxxxxxx>; linux-
>kernel@xxxxxxxxxxxxxxx; Eric Dumazet <edumazet@xxxxxxxxxx>; Kubiak,
>Michal <michal.kubiak@xxxxxxxxx>; Nguyen, Anthony L
><anthony.l.nguyen@xxxxxxxxx>; Nambiar, Amritha
><amritha.nambiar@xxxxxxxxx>; Keller, Jacob E <jacob.e.keller@xxxxxxxxx>;
>Jakub Kicinski <kuba@xxxxxxxxxx>; bpf@xxxxxxxxxxxxxxx; Paolo Abeni
><pabeni@xxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Karlsson,
>Magnus <magnus.karlsson@xxxxxxxxx>
>Subject: [Intel-wired-lan] [PATCH iwl-net v2 4/6] ice: check ICE_VSI_DOWN
>under rtnl_lock when preparing for reset
>
>Consider the following scenario:
>
>.ndo_bpf()		| ice_prepare_for_reset()		|
>________________________|_______________________________________|
>rtnl_lock()		|					|
>ice_down()		|					|
>			| test_bit(ICE_VSI_DOWN) - true		|
>			| ice_dis_vsi() returns			|
>ice_up()		|					|
>			| proceeds to rebuild a running VSI	|
>
>.ndo_bpf() is not the only rtnl-locked callback that toggles the interface to apply
>new configuration. Another example is .set_channels().
>
>To avoid the race condition above, act only after reading ICE_VSI_DOWN under
>rtnl_lock.
>
>Fixes: 0f9d5027a749 ("ice: Refactor VSI allocation, deletion and rebuild flow")
>Reviewed-by: Wojciech Drewek <wojciech.drewek@xxxxxxxxx>
>Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
>---
> drivers/net/ethernet/intel/ice/ice_lib.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>

Tested-by: Chandan Kumar Rout <chandanx.rout@xxxxxxxxx> (A Contingent Worker at Intel)