From 1c56c0994a533ce564843a0d17af7a3e6e68f269 Mon Sep 17 00:00:00 2001 From: Bert Kenward Date: Wed, 11 Jul 2018 11:44:25 +0100 Subject: [PATCH 1/2] sfc: avoid hang from nested use of the filter_sem In some situations we may end up calling down_read while already holding the semaphore for write, thus hanging. This has been seen when setting the MAC address for the interface. The hung task log in this situation includes this stack: down_read efx_ef10_filter_insert efx_ef10_filter_insert_addr_list efx_ef10_filter_vlan_sync_rx_mode efx_ef10_filter_add_vlan efx_ef10_filter_table_probe efx_ef10_set_mac_address efx_set_mac_address dev_set_mac_address In addition, lockdep rightly points out that nested calling of down_read is incorrect. Fixes: c2bebe37c6b6 ("sfc: give ef10 its own rwsem in the filter table instead of filter_lock") Tested-by: Jarod Wilson Signed-off-by: Bert Kenward Signed-off-by: David S. Miller --- drivers/net/ethernet/sfc/ef10.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c index 23f0785c0573..7eeac3d6cfe8 100644 --- a/drivers/net/ethernet/sfc/ef10.c +++ b/drivers/net/ethernet/sfc/ef10.c @@ -4288,9 +4288,9 @@ static int efx_ef10_filter_pri(struct efx_ef10_filter_table *table, return -EPROTONOSUPPORT; } -static s32 efx_ef10_filter_insert(struct efx_nic *efx, - struct efx_filter_spec *spec, - bool replace_equal) +static s32 efx_ef10_filter_insert_locked(struct efx_nic *efx, + struct efx_filter_spec *spec, + bool replace_equal) { DECLARE_BITMAP(mc_rem_map, EFX_EF10_FILTER_SEARCH_LIMIT); struct efx_ef10_nic_data *nic_data = efx->nic_data; @@ -4307,7 +4307,7 @@ static s32 efx_ef10_filter_insert(struct efx_nic *efx, bool is_mc_recip; s32 rc; - down_read(&efx->filter_sem); + WARN_ON(!rwsem_is_locked(&efx->filter_sem)); table = efx->filter_state; down_write(&table->lock); @@ -4498,10 +4498,22 @@ out_unlock: if (rss_locked) mutex_unlock(&efx->rss_lock); up_write(&table->lock); - up_read(&efx->filter_sem); return rc; } +static s32 efx_ef10_filter_insert(struct efx_nic *efx, + struct efx_filter_spec *spec, + bool replace_equal) +{ + s32 ret; + + down_read(&efx->filter_sem); + ret = efx_ef10_filter_insert_locked(efx, spec, replace_equal); + up_read(&efx->filter_sem); + + return ret; +} + static void efx_ef10_filter_update_rx_scatter(struct efx_nic *efx) { /* no need to do anything here on EF10 */ @@ -5285,7 +5297,7 @@ static int efx_ef10_filter_insert_addr_list(struct efx_nic *efx, EFX_WARN_ON_PARANOID(ids[i] != EFX_EF10_FILTER_ID_INVALID); efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO, filter_flags, 0); efx_filter_set_eth_local(&spec, vlan->vid, addr_list[i].addr); - rc = efx_ef10_filter_insert(efx, &spec, true); + rc = efx_ef10_filter_insert_locked(efx, &spec, true); if (rc < 0) { if (rollback) { netif_info(efx, drv, efx->net_dev, @@ -5314,7 +5326,7 @@ static int efx_ef10_filter_insert_addr_list(struct efx_nic *efx, efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO, filter_flags, 0); eth_broadcast_addr(baddr); efx_filter_set_eth_local(&spec, vlan->vid, baddr); - rc = efx_ef10_filter_insert(efx, &spec, true); + rc = efx_ef10_filter_insert_locked(efx, &spec, true); if (rc < 0) { netif_warn(efx, drv, efx->net_dev, "Broadcast filter insert failed rc=%d\n", rc); @@ -5370,7 +5382,7 @@ static int efx_ef10_filter_insert_def(struct efx_nic *efx, if (vlan->vid != EFX_FILTER_VID_UNSPEC) efx_filter_set_eth_local(&spec, vlan->vid, NULL); - rc = efx_ef10_filter_insert(efx, &spec, true); + rc = efx_ef10_filter_insert_locked(efx, &spec, true); if (rc < 0) { const char *um = multicast ? "Multicast" : "Unicast"; const char *encap_name = ""; @@ -5430,7 +5442,7 @@ static int efx_ef10_filter_insert_def(struct efx_nic *efx, filter_flags, 0); eth_broadcast_addr(baddr); efx_filter_set_eth_local(&spec, vlan->vid, baddr); - rc = efx_ef10_filter_insert(efx, &spec, true); + rc = efx_ef10_filter_insert_locked(efx, &spec, true); if (rc < 0) { netif_warn(efx, drv, efx->net_dev, "Broadcast filter insert failed rc=%d\n", From 193f20033c54db0dc9563f722fbafbcd5fa0e80d Mon Sep 17 00:00:00 2001 From: Bert Kenward Date: Wed, 11 Jul 2018 11:45:10 +0100 Subject: [PATCH 2/2] sfc: hold filter_sem consistently during reset We should take and release the filter_sem consistently during the reset process, in the same manner as the mac_lock and reset_lock. For lockdep consistency we also take the filter_sem for write around other calls to efx->type->init(). Fixes: c2bebe37c6b6 ("sfc: give ef10 its own rwsem in the filter table instead of filter_lock") Signed-off-by: Bert Kenward Signed-off-by: David S. Miller --- drivers/net/ethernet/sfc/efx.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c index 570ec72266f3..ce3a177081a8 100644 --- a/drivers/net/ethernet/sfc/efx.c +++ b/drivers/net/ethernet/sfc/efx.c @@ -1871,12 +1871,6 @@ static void efx_remove_filters(struct efx_nic *efx) up_write(&efx->filter_sem); } -static void efx_restore_filters(struct efx_nic *efx) -{ - down_read(&efx->filter_sem); - efx->type->filter_table_restore(efx); - up_read(&efx->filter_sem); -} /************************************************************************** * @@ -2688,6 +2682,7 @@ void efx_reset_down(struct efx_nic *efx, enum reset_type method) efx_disable_interrupts(efx); mutex_lock(&efx->mac_lock); + down_write(&efx->filter_sem); mutex_lock(&efx->rss_lock); if (efx->port_initialized && method != RESET_TYPE_INVISIBLE && method != RESET_TYPE_DATAPATH) @@ -2745,9 +2740,8 @@ int efx_reset_up(struct efx_nic *efx, enum reset_type method, bool ok) if (efx->type->rx_restore_rss_contexts) efx->type->rx_restore_rss_contexts(efx); mutex_unlock(&efx->rss_lock); - down_read(&efx->filter_sem); - efx_restore_filters(efx); - up_read(&efx->filter_sem); + efx->type->filter_table_restore(efx); + up_write(&efx->filter_sem); if (efx->type->sriov_reset) efx->type->sriov_reset(efx); @@ -2764,6 +2758,7 @@ fail: efx->port_initialized = false; mutex_unlock(&efx->rss_lock); + up_write(&efx->filter_sem); mutex_unlock(&efx->mac_lock); return rc; @@ -3473,7 +3468,9 @@ static int efx_pci_probe_main(struct efx_nic *efx) efx_init_napi(efx); + down_write(&efx->filter_sem); rc = efx->type->init(efx); + up_write(&efx->filter_sem); if (rc) { netif_err(efx, probe, efx->net_dev, "failed to initialise NIC\n"); @@ -3765,7 +3762,9 @@ static int efx_pm_resume(struct device *dev) rc = efx->type->reset(efx, RESET_TYPE_ALL); if (rc) return rc; + down_write(&efx->filter_sem); rc = efx->type->init(efx); + up_write(&efx->filter_sem); if (rc) return rc; rc = efx_pm_thaw(dev);