| Message ID | 20240823095933.17922-3-larysa.zaremba@intel.com |
|---|---|
| State | Accepted |
| Delegated to: | Anthony Nguyen |
| Headers | show |
| Series | ice: fix synchronization between .ndo_bpf() and reset | expand |
On Fri, Aug 23, 2024 at 11:59:27AM +0200, Larysa Zaremba wrote: > 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> > ---
diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h index caaa10157909..ce8b5505b16d 100644 --- a/drivers/net/ethernet/intel/ice/ice.h +++ b/drivers/net/ethernet/intel/ice/ice.h @@ -318,6 +318,7 @@ 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 */ }; @@ -411,6 +412,7 @@ 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 57ec770c52fc..9978bbcb2401 100644 --- a/drivers/net/ethernet/intel/ice/ice_lib.c +++ b/drivers/net/ethernet/intel/ice/ice_lib.c @@ -447,6 +447,7 @@ 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); } @@ -626,6 +627,8 @@ 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; @@ -2973,19 +2976,23 @@ 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); 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); @@ -2993,22 +3000,23 @@ 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 2d286a4609a5..e92f43850671 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -595,6 +595,7 @@ 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)) @@ -2995,7 +2996,8 @@ 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; } @@ -3067,21 +3069,28 @@ 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 240a7bec242b..a659951fa987 100644 --- a/drivers/net/ethernet/intel/ice/ice_xsk.c +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c @@ -390,7 +390,8 @@ 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];
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> --- 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(-)