> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of
> Maciej Fijalkowski
> Sent: Tuesday, October 26, 2021 10:17 PM
> To: intel-wired-lan@xxxxxxxxxxxxxxxx
> Cc: Lobakin, Alexandr <alexandr.lobakin@xxxxxxxxx>;
> netdev@xxxxxxxxxxxxxxx; Plantykow, Marta A
> <marta.a.plantykow@xxxxxxxxx>; kuba@xxxxxxxxxx; bpf@xxxxxxxxxxxxxxx;
> davem@xxxxxxxxxxxxx; Karlsson, Magnus <magnus.karlsson@xxxxxxxxx>
> Subject: [Intel-wired-lan] [PATCH intel-next 1/2] ice: fix vsi->txq_map sizing
>
> The approach of having XDP queue per CPU regardless of user's setting
> exposed a hidden bug that could occur in case when Rx queue count differ
> from Tx queue count. Currently vsi->txq_map's size is equal to the doubled
> vsi->alloc_txq, which is not correct due to the fact that XDP rings were
> previously based on the Rx queue count. Below splat can be seen when
> ethtool -L is used and XDP rings are configured:
>
> [ 682.875339] BUG: kernel NULL pointer dereference, address:
> 000000000000000f [ 682.883403] #PF: supervisor read access in kernel mode
> [ 682.889345] #PF: error_code(0x0000) - not-present page [ 682.895289]
> PGD 0 P4D 0 [ 682.898218] Oops: 0000 [#1] PREEMPT SMP PTI
> [ 682.903055] CPU: 42 PID: 2878 Comm: ethtool Tainted: G OE 5.15.0-
> rc5+ #1
> [ 682.912214] Hardware name: Intel Corp. GRANTLEY/GRANTLEY, BIOS
> GRRFCRB1.86B.0276.D07.1605190235 05/19/2016 [ 682.923380] RIP:
> 0010:devres_remove+0x44/0x130 [ 682.928527] Code: 49 89 f4 55 48 89 fd
> 4c 89 ff 53 48 83 ec 10 e8 92 b9 49 00 48 8b 9d a8 02 00 00 48 8d 8d a0 02 00
> 00 49 89 c2 48 39 cb 74 0f <4c> 3b 63 10 74 25 48 8b 5b 08 48 39 cb 75 f1 4c
> 89 ff 4c 89 d6 e8 [ 682.950237] RSP: 0018:ffffc90006a679f0 EFLAGS:
> 00010002 [ 682.956285] RAX: 0000000000000286 RBX: ffffffffffffffff RCX:
> ffff88908343a370 [ 682.964538] RDX: 0000000000000001 RSI:
> ffffffff81690d60 RDI: 0000000000000000 [ 682.972789] RBP:
> ffff88908343a0d0 R08: 0000000000000000 R09: 0000000000000000 [
> 682.981040] R10: 0000000000000286 R11: 3fffffffffffffff R12: ffffffff81690d60
> [ 682.989282] R13: ffffffff81690a00 R14: ffff8890819807a8 R15:
> ffff88908343a36c [ 682.997535] FS: 00007f08c7bfa740(0000)
> GS:ffff88a03fd00000(0000) knlGS:0000000000000000 [ 683.006910] CS: 0010
> DS: 0000 ES: 0000 CR0: 0000000080050033 [ 683.013557] CR2:
> 000000000000000f CR3: 0000001080a66003 CR4: 00000000003706e0 [
> 683.021819] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> 0000000000000000 [ 683.030075] DR3: 0000000000000000 DR6:
> 00000000fffe0ff0 DR7: 0000000000000400 [ 683.038336] Call Trace:
> [ 683.041167] devm_kfree+0x33/0x50
> [ 683.045004] ice_vsi_free_arrays+0x5e/0xc0 [ice] [ 683.050380]
> ice_vsi_rebuild+0x4c8/0x750 [ice] [ 683.055543]
> ice_vsi_recfg_qs+0x9a/0x110 [ice] [ 683.060697]
> ice_set_channels+0x14f/0x290 [ice] [ 683.065962]
> ethnl_set_channels+0x333/0x3f0 [ 683.070807]
> genl_family_rcv_msg_doit+0xea/0x150
> [ 683.076152] genl_rcv_msg+0xde/0x1d0
> [ 683.080289] ? channels_prepare_data+0x60/0x60 [ 683.085432] ?
> genl_get_cmd+0xd0/0xd0 [ 683.089667] netlink_rcv_skb+0x50/0xf0 [
> 683.094006] genl_rcv+0x24/0x40 [ 683.097638]
> netlink_unicast+0x239/0x340 [ 683.102177] netlink_sendmsg+0x22e/0x470 [
> 683.106717] sock_sendmsg+0x5e/0x60 [ 683.110756]
> __sys_sendto+0xee/0x150 [ 683.114894] ? handle_mm_fault+0xd0/0x2a0 [
> 683.119535] ? do_user_addr_fault+0x1f3/0x690 [ 683.134173]
> __x64_sys_sendto+0x25/0x30 [ 683.148231] do_syscall_64+0x3b/0xc0 [
> 683.161992] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Fix this by taking into account the value that num_possible_cpus() yields in
> addition to vsi->alloc_txq instead of doubling the latter.
>
> Fixes: efc2214b6047 ("ice: Add support for XDP")
> Fixes: 22bf877e528f ("ice: introduce XDP_TX fallback path")
> Reviewed-by: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
> ---
> drivers/net/ethernet/intel/ice/ice_lib.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
Tested-by: Kiran Bhandare <kiranx.bhandare@xxxxxxxxx> A Contingent Worker at Intel
