Merge tag 'rcu.6.4.april5.2023.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux

Pull RCU updates from Joel Fernandes:

 - Updates and additions to MAINTAINERS files, with Boqun being added to
   the RCU entry and Zqiang being added as an RCU reviewer.

   I have also transitioned from reviewer to maintainer; however, Paul
   will be taking over sending RCU pull-requests for the next merge
   window.

 - Resolution of hotplug warning in nohz code, achieved by fixing
   cpu_is_hotpluggable() through interaction with the nohz subsystem.

   Tick dependency modifications by Zqiang, focusing on fixing usage of
   the TICK_DEP_BIT_RCU_EXP bitmask.

 - Avoid needless calls to the rcu-lazy shrinker for CONFIG_RCU_LAZY=n
   kernels, fixed by Zqiang.

 - Improvements to rcu-tasks stall reporting by Neeraj.

 - Initial renaming of k[v]free_rcu() to k[v]free_rcu_mightsleep() for
   increased robustness, affecting several components like mac802154,
   drbd, vmw_vmci, tracing, and more.

   A report by Eric Dumazet showed that the API could be unknowingly
   used in an atomic context, so we'd rather make sure they know what
   they're asking for by being explicit:

      https://lore.kernel.org/all/20221202052847.2623997-1-edumazet@google.com/

 - Documentation updates, including corrections to spelling,
   clarifications in comments, and improvements to the srcu_size_state
   comments.

 - Better srcu_struct cache locality for readers, by adjusting the size
   of srcu_struct in support of SRCU usage by Christoph Hellwig.

 - Teach lockdep to detect deadlocks between srcu_read_lock() vs
   synchronize_srcu() contributed by Boqun.

   Previously lockdep could not detect such deadlocks, now it can.

 - Integration of rcutorture and rcu-related tools, targeted for v6.4
   from Boqun's tree, featuring new SRCU deadlock scenarios, test_nmis
   module parameter, and more

 - Miscellaneous changes, various code cleanups and comment improvements

* tag 'rcu.6.4.april5.2023.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux: (71 commits)
  checkpatch: Error out if deprecated RCU API used
  mac802154: Rename kfree_rcu() to kvfree_rcu_mightsleep()
  rcuscale: Rename kfree_rcu() to kfree_rcu_mightsleep()
  ext4/super: Rename kfree_rcu() to kfree_rcu_mightsleep()
  net/mlx5: Rename kfree_rcu() to kfree_rcu_mightsleep()
  net/sysctl: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  lib/test_vmalloc.c: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  tracing: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  misc: vmw_vmci: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  drbd: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access
  rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed
  rcu-tasks: Report stalls during synchronize_srcu() in rcu_tasks_postscan()
  rcu: Permit start_poll_synchronize_rcu_expedited() to be invoked early
  rcu: Remove never-set needwake assignment from rcu_report_qs_rdp()
  rcu: Register rcu-lazy shrinker only for CONFIG_RCU_LAZY=y kernels
  rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check
  rcu: Fix set/clear TICK_DEP_BIT_RCU_EXP bitmask race
  rcu/trace: use strscpy() to instead of strncpy()
  tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem
  ...

8 files changed, 13 insertions, 12 deletions

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 182c6122f815..c1815b9dae68 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -487,7 +487,8 @@ static const struct attribute_group *cpu_root_attr_groups[] = {
 bool cpu_is_hotpluggable(unsigned int cpu)
 {
 	struct device *dev = get_cpu_device(cpu);
-	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
+	return dev && container_of(dev, struct cpu, dev)->hotpluggable
+		&& tick_nohz_cpu_hotpluggable(cpu);
 }
 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
 
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 60757ac31701..f49f2a5282e1 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1615,7 +1615,7 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 			drbd_send_sync_param(peer_device);
 	}
 
-	kvfree_rcu(old_disk_conf);
+	kvfree_rcu_mightsleep(old_disk_conf);
 	kfree(old_plan);
 	mod_timer(&device->request_timer, jiffies + HZ);
 	goto success;
@@ -2446,7 +2446,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 
 	mutex_unlock(&connection->resource->conf_update);
 	mutex_unlock(&connection->data.mutex);
-	kvfree_rcu(old_net_conf);
+	kvfree_rcu_mightsleep(old_net_conf);
 
 	if (connection->cstate >= C_WF_REPORT_PARAMS) {
 		struct drbd_peer_device *peer_device;
@@ -2860,7 +2860,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 		new_disk_conf->disk_size = (sector_t)rs.resize_size;
 		rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
 		mutex_unlock(&device->resource->conf_update);
-		kvfree_rcu(old_disk_conf);
+		kvfree_rcu_mightsleep(old_disk_conf);
 		new_disk_conf = NULL;
 	}
 
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 757f4692b5bd..e197b2a465d2 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3759,7 +3759,7 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in
 		drbd_info(connection, "peer data-integrity-alg: %s\n",
 			  integrity_alg[0] ? integrity_alg : "(none)");
 
-	kvfree_rcu(old_net_conf);
+	kvfree_rcu_mightsleep(old_net_conf);
 	return 0;
 
 disconnect_rcu_unlock:
@@ -4127,7 +4127,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 
 			rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
 			mutex_unlock(&connection->resource->conf_update);
-			kvfree_rcu(old_disk_conf);
+			kvfree_rcu_mightsleep(old_disk_conf);
 
 			drbd_info(device, "Peer sets u_size to %lu sectors (old: %lu)\n",
 				 (unsigned long)p_usize, (unsigned long)my_usize);
diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
index 75d13ea0024f..2aeea295fa28 100644
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -2071,7 +2071,7 @@ static int w_after_conn_state_ch(struct drbd_work *w, int unused)
 		conn_free_crypto(connection);
 		mutex_unlock(&connection->resource->conf_update);
 
-		kvfree_rcu(old_conf);
+		kvfree_rcu_mightsleep(old_conf);
 	}
 
 	if (ns_max.susp_fen) {
diff --git a/drivers/misc/vmw_vmci/vmci_context.c b/drivers/misc/vmw_vmci/vmci_context.c
index 172696abce31..f22b44827e92 100644
--- a/drivers/misc/vmw_vmci/vmci_context.c
+++ b/drivers/misc/vmw_vmci/vmci_context.c
@@ -687,7 +687,7 @@ int vmci_ctx_remove_notification(u32 context_id, u32 remote_cid)
 	spin_unlock(&context->lock);
 
 	if (notifier)
-		kvfree_rcu(notifier);
+		kvfree_rcu_mightsleep(notifier);
 
 	vmci_ctx_put(context);
 
diff --git a/drivers/misc/vmw_vmci/vmci_event.c b/drivers/misc/vmw_vmci/vmci_event.c
index 2100297c94ad..5d7ac07623c2 100644
--- a/drivers/misc/vmw_vmci/vmci_event.c
+++ b/drivers/misc/vmw_vmci/vmci_event.c
@@ -209,7 +209,7 @@ int vmci_event_unsubscribe(u32 sub_id)
 	if (!s)
 		return VMCI_ERROR_NOT_FOUND;
 
-	kvfree_rcu(s);
+	kvfree_rcu_mightsleep(s);
 
 	return VMCI_SUCCESS;
 }
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc/int_port.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc/int_port.c
index ca834bbcb44f..8afcec0c5d3c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc/int_port.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc/int_port.c
@@ -242,7 +242,7 @@ mlx5e_int_port_remove(struct mlx5e_tc_int_port_priv *priv,
 		mlx5_del_flow_rules(int_port->rx_rule);
 	mapping_remove(ctx, int_port->mapping);
 	mlx5e_int_port_metadata_free(priv, int_port->match_metadata);
-	kfree_rcu(int_port);
+	kfree_rcu_mightsleep(int_port);
 	priv->num_ports--;
 }
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c
index 33b3620ea45c..51f1cd8364c2 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c
@@ -670,7 +670,7 @@ static int mlx5e_macsec_del_txsa(struct macsec_context *ctx)
 
 	mlx5e_macsec_cleanup_sa(macsec, tx_sa, true);
 	mlx5_destroy_encryption_key(macsec->mdev, tx_sa->enc_key_id);
-	kfree_rcu(tx_sa);
+	kfree_rcu_mightsleep(tx_sa);
 	macsec_device->tx_sa[assoc_num] = NULL;
 
 out:
@@ -849,7 +849,7 @@ static void macsec_del_rxsc_ctx(struct mlx5e_macsec *macsec, struct mlx5e_macsec
 	xa_erase(&macsec->sc_xarray, rx_sc->sc_xarray_element->fs_id);
 	metadata_dst_free(rx_sc->md_dst);
 	kfree(rx_sc->sc_xarray_element);
-	kfree_rcu(rx_sc);
+	kfree_rcu_mightsleep(rx_sc);
 }
 
 static int mlx5e_macsec_del_rxsc(struct macsec_context *ctx)