6.6-stable review patch. If anyone has any objections, please let me know.
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From: Larysa Zaremba larysa.zaremba@intel.com
[ Upstream commit 2504b8405768a57a71e660dbfd5abd59f679a03f ]
The main threat to data consistency in ice_xdp() is a possible asynchronous PF reset. It can be triggered by a user or by TX timeout handler.
XDP setup and PF reset code access the same resources in the following sections: * ice_vsi_close() in ice_prepare_for_reset() - already rtnl-locked * ice_vsi_rebuild() for the PF VSI - not protected * ice_vsi_open() - already rtnl-locked
With an unfortunate timing, such accesses can result in a crash such as the one below:
[ +1.999878] ice 0000:b1:00.0: Registered XDP mem model MEM_TYPE_XSK_BUFF_POOL on Rx ring 14 [ +2.002992] ice 0000:b1:00.0: Registered XDP mem model MEM_TYPE_XSK_BUFF_POOL on Rx ring 18 [Mar15 18:17] ice 0000:b1:00.0 ens801f0np0: NETDEV WATCHDOG: CPU: 38: transmit queue 14 timed out 80692736 ms [ +0.000093] ice 0000:b1:00.0 ens801f0np0: tx_timeout: VSI_num: 6, Q 14, NTC: 0x0, HW_HEAD: 0x0, NTU: 0x0, INT: 0x4000001 [ +0.000012] ice 0000:b1:00.0 ens801f0np0: tx_timeout recovery level 1, txqueue 14 [ +0.394718] ice 0000:b1:00.0: PTP reset successful [ +0.006184] BUG: kernel NULL pointer dereference, address: 0000000000000098 [ +0.000045] #PF: supervisor read access in kernel mode [ +0.000023] #PF: error_code(0x0000) - not-present page [ +0.000023] PGD 0 P4D 0 [ +0.000018] Oops: 0000 [#1] PREEMPT SMP NOPTI [ +0.000023] CPU: 38 PID: 7540 Comm: kworker/38:1 Not tainted 6.8.0-rc7 #1 [ +0.000031] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0014.082620210524 08/26/2021 [ +0.000036] Workqueue: ice ice_service_task [ice] [ +0.000183] RIP: 0010:ice_clean_tx_ring+0xa/0xd0 [ice] [...] [ +0.000013] Call Trace: [ +0.000016] <TASK> [ +0.000014] ? __die+0x1f/0x70 [ +0.000029] ? page_fault_oops+0x171/0x4f0 [ +0.000029] ? schedule+0x3b/0xd0 [ +0.000027] ? exc_page_fault+0x7b/0x180 [ +0.000022] ? asm_exc_page_fault+0x22/0x30 [ +0.000031] ? ice_clean_tx_ring+0xa/0xd0 [ice] [ +0.000194] ice_free_tx_ring+0xe/0x60 [ice] [ +0.000186] ice_destroy_xdp_rings+0x157/0x310 [ice] [ +0.000151] ice_vsi_decfg+0x53/0xe0 [ice] [ +0.000180] ice_vsi_rebuild+0x239/0x540 [ice] [ +0.000186] ice_vsi_rebuild_by_type+0x76/0x180 [ice] [ +0.000145] ice_rebuild+0x18c/0x840 [ice] [ +0.000145] ? delay_tsc+0x4a/0xc0 [ +0.000022] ? delay_tsc+0x92/0xc0 [ +0.000020] ice_do_reset+0x140/0x180 [ice] [ +0.000886] ice_service_task+0x404/0x1030 [ice] [ +0.000824] process_one_work+0x171/0x340 [ +0.000685] worker_thread+0x277/0x3a0 [ +0.000675] ? preempt_count_add+0x6a/0xa0 [ +0.000677] ? _raw_spin_lock_irqsave+0x23/0x50 [ +0.000679] ? __pfx_worker_thread+0x10/0x10 [ +0.000653] kthread+0xf0/0x120 [ +0.000635] ? __pfx_kthread+0x10/0x10 [ +0.000616] ret_from_fork+0x2d/0x50 [ +0.000612] ? __pfx_kthread+0x10/0x10 [ +0.000604] ret_from_fork_asm+0x1b/0x30 [ +0.000604] </TASK>
The previous way of handling this through returning -EBUSY is not viable, particularly when destroying AF_XDP socket, because the kernel proceeds with removal anyway.
There is plenty of code between those calls and there is no need to create a large critical section that covers all of them, same as there is no need to protect ice_vsi_rebuild() with rtnl_lock().
Add xdp_state_lock mutex to protect ice_vsi_rebuild() and ice_xdp().
Leaving unprotected sections in between would result in two states that have to be considered: 1. when the VSI is closed, but not yet rebuild 2. when VSI is already rebuild, but not yet open
The latter case is actually already handled through !netif_running() case, we just need to adjust flag checking a little. The former one is not as trivial, because between ice_vsi_close() and ice_vsi_rebuild(), a lot of hardware interaction happens, this can make adding/deleting rings exit with an error. Luckily, VSI rebuild is pending and can apply new configuration for us in a managed fashion.
Therefore, add an additional VSI state flag ICE_VSI_REBUILD_PENDING to indicate that ice_xdp() can just hot-swap the program.
Also, as ice_vsi_rebuild() flow is touched in this patch, make it more consistent by deconfiguring VSI when coalesce allocation fails.
Fixes: 2d4238f55697 ("ice: Add support for AF_XDP") Fixes: efc2214b6047 ("ice: Add support for XDP") Reviewed-by: Wojciech Drewek wojciech.drewek@intel.com Reviewed-by: Jacob Keller jacob.e.keller@intel.com Tested-by: Chandan Kumar Rout chandanx.rout@intel.com Signed-off-by: Larysa Zaremba larysa.zaremba@intel.com Reviewed-by: Maciej Fijalkowski maciej.fijalkowski@intel.com Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/intel/ice/ice.h | 2 ++ drivers/net/ethernet/intel/ice/ice_lib.c | 34 ++++++++++++++--------- drivers/net/ethernet/intel/ice/ice_main.c | 19 +++++++++---- drivers/net/ethernet/intel/ice/ice_xsk.c | 3 +- 4 files changed, 39 insertions(+), 19 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h index c7962f322db2..7b3ce30ba38f 100644 --- a/drivers/net/ethernet/intel/ice/ice.h +++ b/drivers/net/ethernet/intel/ice/ice.h @@ -313,6 +313,7 @@ enum ice_vsi_state { ICE_VSI_UMAC_FLTR_CHANGED, ICE_VSI_MMAC_FLTR_CHANGED, ICE_VSI_PROMISC_CHANGED, + ICE_VSI_REBUILD_PENDING, ICE_VSI_STATE_NBITS /* must be last */ };
@@ -409,6 +410,7 @@ struct ice_vsi { struct ice_tx_ring **xdp_rings; /* XDP ring array */ u16 num_xdp_txq; /* Used XDP queues */ u8 xdp_mapping_mode; /* ICE_MAP_MODE_[CONTIG|SCATTER] */ + struct mutex xdp_state_lock;
struct net_device **target_netdevs;
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c index 13ca3342a0ce..b3010a53f1b4 100644 --- a/drivers/net/ethernet/intel/ice/ice_lib.c +++ b/drivers/net/ethernet/intel/ice/ice_lib.c @@ -459,6 +459,7 @@ static void ice_vsi_free(struct ice_vsi *vsi)
ice_vsi_free_stats(vsi); ice_vsi_free_arrays(vsi); + mutex_destroy(&vsi->xdp_state_lock); mutex_unlock(&pf->sw_mutex); devm_kfree(dev, vsi); } @@ -660,6 +661,8 @@ static struct ice_vsi *ice_vsi_alloc(struct ice_pf *pf) pf->next_vsi = ice_get_free_slot(pf->vsi, pf->num_alloc_vsi, pf->next_vsi);
+ mutex_init(&vsi->xdp_state_lock); + unlock_pf: mutex_unlock(&pf->sw_mutex); return vsi; @@ -3164,19 +3167,23 @@ int ice_vsi_rebuild(struct ice_vsi *vsi, u32 vsi_flags) if (WARN_ON(vsi->type == ICE_VSI_VF && !vsi->vf)) return -EINVAL;
+ mutex_lock(&vsi->xdp_state_lock); + ret = ice_vsi_realloc_stat_arrays(vsi); if (ret) - goto err_vsi_cfg; + goto unlock;
ice_vsi_decfg(vsi); ret = ice_vsi_cfg_def(vsi, ¶ms); if (ret) - goto err_vsi_cfg; + goto unlock;
coalesce = kcalloc(vsi->num_q_vectors, sizeof(struct ice_coalesce_stored), GFP_KERNEL); - if (!coalesce) - return -ENOMEM; + if (!coalesce) { + ret = -ENOMEM; + goto decfg; + }
prev_num_q_vectors = ice_vsi_rebuild_get_coalesce(vsi, coalesce);
@@ -3184,22 +3191,23 @@ int ice_vsi_rebuild(struct ice_vsi *vsi, u32 vsi_flags) if (ret) { if (vsi_flags & ICE_VSI_FLAG_INIT) { ret = -EIO; - goto err_vsi_cfg_tc_lan; + goto free_coalesce; }
- kfree(coalesce); - return ice_schedule_reset(pf, ICE_RESET_PFR); + ret = ice_schedule_reset(pf, ICE_RESET_PFR); + goto free_coalesce; }
ice_vsi_rebuild_set_coalesce(vsi, coalesce, prev_num_q_vectors); - kfree(coalesce); + clear_bit(ICE_VSI_REBUILD_PENDING, vsi->state);
- return 0; - -err_vsi_cfg_tc_lan: - ice_vsi_decfg(vsi); +free_coalesce: kfree(coalesce); -err_vsi_cfg: +decfg: + if (ret) + ice_vsi_decfg(vsi); +unlock: + mutex_unlock(&vsi->xdp_state_lock); return ret; }
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c index ffe6e74b9fea..3ee92b0e62ff 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -614,6 +614,7 @@ ice_prepare_for_reset(struct ice_pf *pf, enum ice_reset_req reset_type) /* clear SW filtering DB */ ice_clear_hw_tbls(hw); /* disable the VSIs and their queues that are not already DOWN */ + set_bit(ICE_VSI_REBUILD_PENDING, ice_get_main_vsi(pf)->state); ice_pf_dis_all_vsi(pf, false);
if (test_bit(ICE_FLAG_PTP_SUPPORTED, pf->flags)) @@ -2942,7 +2943,8 @@ ice_xdp_setup_prog(struct ice_vsi *vsi, struct bpf_prog *prog, }
/* hot swap progs and avoid toggling link */ - if (ice_is_xdp_ena_vsi(vsi) == !!prog) { + if (ice_is_xdp_ena_vsi(vsi) == !!prog || + test_bit(ICE_VSI_REBUILD_PENDING, vsi->state)) { ice_vsi_assign_bpf_prog(vsi, prog); return 0; } @@ -3014,21 +3016,28 @@ static int ice_xdp(struct net_device *dev, struct netdev_bpf *xdp) { struct ice_netdev_priv *np = netdev_priv(dev); struct ice_vsi *vsi = np->vsi; + int ret;
if (vsi->type != ICE_VSI_PF) { NL_SET_ERR_MSG_MOD(xdp->extack, "XDP can be loaded only on PF VSI"); return -EINVAL; }
+ mutex_lock(&vsi->xdp_state_lock); + switch (xdp->command) { case XDP_SETUP_PROG: - return ice_xdp_setup_prog(vsi, xdp->prog, xdp->extack); + ret = ice_xdp_setup_prog(vsi, xdp->prog, xdp->extack); + break; case XDP_SETUP_XSK_POOL: - return ice_xsk_pool_setup(vsi, xdp->xsk.pool, - xdp->xsk.queue_id); + ret = ice_xsk_pool_setup(vsi, xdp->xsk.pool, xdp->xsk.queue_id); + break; default: - return -EINVAL; + ret = -EINVAL; } + + mutex_unlock(&vsi->xdp_state_lock); + return ret; }
/** diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c index 67511153081a..9a9b8698881b 100644 --- a/drivers/net/ethernet/intel/ice/ice_xsk.c +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c @@ -396,7 +396,8 @@ int ice_xsk_pool_setup(struct ice_vsi *vsi, struct xsk_buff_pool *pool, u16 qid) goto failure; }
- if_running = netif_running(vsi->netdev) && ice_is_xdp_ena_vsi(vsi); + if_running = !test_bit(ICE_VSI_DOWN, vsi->state) && + ice_is_xdp_ena_vsi(vsi);
if (if_running) { struct ice_rx_ring *rx_ring = vsi->rx_rings[qid];