From: Moshe Shemesh moshe@nvidia.com
[ Upstream commit d59b73a66e5e0682442b6d7b4965364e57078b80 ]
Add a lock_class_key per mlx5 device to avoid a false positive "possible circular locking dependency" warning by lockdep, on flows which lock more than one mlx5 device, such as adding SF.
kernel log: ====================================================== WARNING: possible circular locking dependency detected 5.19.0-rc8+ #2 Not tainted ------------------------------------------------------ kworker/u20:0/8 is trying to acquire lock: ffff88812dfe0d98 (&dev->intf_state_mutex){+.+.}-{3:3}, at: mlx5_init_one+0x2e/0x490 [mlx5_core]
but task is already holding lock: ffff888101aa7898 (&(¬ifier->n_head)->rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x5a/0x130
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&(¬ifier->n_head)->rwsem){++++}-{3:3}: down_write+0x90/0x150 blocking_notifier_chain_register+0x53/0xa0 mlx5_sf_table_init+0x369/0x4a0 [mlx5_core] mlx5_init_one+0x261/0x490 [mlx5_core] probe_one+0x430/0x680 [mlx5_core] local_pci_probe+0xd6/0x170 work_for_cpu_fn+0x4e/0xa0 process_one_work+0x7c2/0x1340 worker_thread+0x6f6/0xec0 kthread+0x28f/0x330 ret_from_fork+0x1f/0x30
-> #0 (&dev->intf_state_mutex){+.+.}-{3:3}: __lock_acquire+0x2fc7/0x6720 lock_acquire+0x1c1/0x550 __mutex_lock+0x12c/0x14b0 mlx5_init_one+0x2e/0x490 [mlx5_core] mlx5_sf_dev_probe+0x29c/0x370 [mlx5_core] auxiliary_bus_probe+0x9d/0xe0 really_probe+0x1e0/0xaa0 __driver_probe_device+0x219/0x480 driver_probe_device+0x49/0x130 __device_attach_driver+0x1b8/0x280 bus_for_each_drv+0x123/0x1a0 __device_attach+0x1a3/0x460 bus_probe_device+0x1a2/0x260 device_add+0x9b1/0x1b40 __auxiliary_device_add+0x88/0xc0 mlx5_sf_dev_state_change_handler+0x67e/0x9d0 [mlx5_core] blocking_notifier_call_chain+0xd5/0x130 mlx5_vhca_state_work_handler+0x2b0/0x3f0 [mlx5_core] process_one_work+0x7c2/0x1340 worker_thread+0x59d/0xec0 kthread+0x28f/0x330 ret_from_fork+0x1f/0x30
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- lock(&(¬ifier->n_head)->rwsem); lock(&dev->intf_state_mutex); lock(&(¬ifier->n_head)->rwsem); lock(&dev->intf_state_mutex);
*** DEADLOCK ***
4 locks held by kworker/u20:0/8: #0: ffff888150612938 ((wq_completion)mlx5_events){+.+.}-{0:0}, at: process_one_work+0x6e2/0x1340 #1: ffff888100cafdb8 ((work_completion)(&work->work)#3){+.+.}-{0:0}, at: process_one_work+0x70f/0x1340 #2: ffff888101aa7898 (&(¬ifier->n_head)->rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x5a/0x130 #3: ffff88813682d0e8 (&dev->mutex){....}-{3:3}, at:__device_attach+0x76/0x460
stack backtrace: CPU: 6 PID: 8 Comm: kworker/u20:0 Not tainted 5.19.0-rc8+ Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Workqueue: mlx5_events mlx5_vhca_state_work_handler [mlx5_core] Call Trace: <TASK> dump_stack_lvl+0x57/0x7d check_noncircular+0x278/0x300 ? print_circular_bug+0x460/0x460 ? lock_chain_count+0x20/0x20 ? register_lock_class+0x1880/0x1880 __lock_acquire+0x2fc7/0x6720 ? register_lock_class+0x1880/0x1880 ? register_lock_class+0x1880/0x1880 lock_acquire+0x1c1/0x550 ? mlx5_init_one+0x2e/0x490 [mlx5_core] ? lockdep_hardirqs_on_prepare+0x400/0x400 __mutex_lock+0x12c/0x14b0 ? mlx5_init_one+0x2e/0x490 [mlx5_core] ? mlx5_init_one+0x2e/0x490 [mlx5_core] ? _raw_read_unlock+0x1f/0x30 ? mutex_lock_io_nested+0x1320/0x1320 ? __ioremap_caller.constprop.0+0x306/0x490 ? mlx5_sf_dev_probe+0x269/0x370 [mlx5_core] ? iounmap+0x160/0x160 mlx5_init_one+0x2e/0x490 [mlx5_core] mlx5_sf_dev_probe+0x29c/0x370 [mlx5_core] ? mlx5_sf_dev_remove+0x130/0x130 [mlx5_core] auxiliary_bus_probe+0x9d/0xe0 really_probe+0x1e0/0xaa0 __driver_probe_device+0x219/0x480 ? auxiliary_match_id+0xe9/0x140 driver_probe_device+0x49/0x130 __device_attach_driver+0x1b8/0x280 ? driver_allows_async_probing+0x140/0x140 bus_for_each_drv+0x123/0x1a0 ? bus_for_each_dev+0x1a0/0x1a0 ? lockdep_hardirqs_on_prepare+0x286/0x400 ? trace_hardirqs_on+0x2d/0x100 __device_attach+0x1a3/0x460 ? device_driver_attach+0x1e0/0x1e0 ? kobject_uevent_env+0x22d/0xf10 bus_probe_device+0x1a2/0x260 device_add+0x9b1/0x1b40 ? dev_set_name+0xab/0xe0 ? __fw_devlink_link_to_suppliers+0x260/0x260 ? memset+0x20/0x40 ? lockdep_init_map_type+0x21a/0x7d0 __auxiliary_device_add+0x88/0xc0 ? auxiliary_device_init+0x86/0xa0 mlx5_sf_dev_state_change_handler+0x67e/0x9d0 [mlx5_core] blocking_notifier_call_chain+0xd5/0x130 mlx5_vhca_state_work_handler+0x2b0/0x3f0 [mlx5_core] ? mlx5_vhca_event_arm+0x100/0x100 [mlx5_core] ? lock_downgrade+0x6e0/0x6e0 ? lockdep_hardirqs_on_prepare+0x286/0x400 process_one_work+0x7c2/0x1340 ? lockdep_hardirqs_on_prepare+0x400/0x400 ? pwq_dec_nr_in_flight+0x230/0x230 ? rwlock_bug.part.0+0x90/0x90 worker_thread+0x59d/0xec0 ? process_one_work+0x1340/0x1340 kthread+0x28f/0x330 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 </TASK>
Fixes: 6a3273217469 ("net/mlx5: SF, Port function state change support") Signed-off-by: Moshe Shemesh moshe@nvidia.com Reviewed-by: Shay Drory shayd@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/main.c | 4 ++++ include/linux/mlx5/driver.h | 1 + 2 files changed, 5 insertions(+)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c index 5a6606c843edf..740065e21181d 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c @@ -1427,7 +1427,9 @@ int mlx5_mdev_init(struct mlx5_core_dev *dev, int profile_idx) memcpy(&dev->profile, &profile[profile_idx], sizeof(dev->profile)); INIT_LIST_HEAD(&priv->ctx_list); spin_lock_init(&priv->ctx_lock); + lockdep_register_key(&dev->lock_key); mutex_init(&dev->intf_state_mutex); + lockdep_set_class(&dev->intf_state_mutex, &dev->lock_key);
mutex_init(&priv->bfregs.reg_head.lock); mutex_init(&priv->bfregs.wc_head.lock); @@ -1474,6 +1476,7 @@ int mlx5_mdev_init(struct mlx5_core_dev *dev, int profile_idx) mutex_destroy(&priv->bfregs.wc_head.lock); mutex_destroy(&priv->bfregs.reg_head.lock); mutex_destroy(&dev->intf_state_mutex); + lockdep_unregister_key(&dev->lock_key); return err; }
@@ -1491,6 +1494,7 @@ void mlx5_mdev_uninit(struct mlx5_core_dev *dev) mutex_destroy(&priv->bfregs.wc_head.lock); mutex_destroy(&priv->bfregs.reg_head.lock); mutex_destroy(&dev->intf_state_mutex); + lockdep_unregister_key(&dev->lock_key); }
static int probe_one(struct pci_dev *pdev, const struct pci_device_id *id) diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h index f17d2101af7a0..4c678de4608dd 100644 --- a/include/linux/mlx5/driver.h +++ b/include/linux/mlx5/driver.h @@ -759,6 +759,7 @@ struct mlx5_core_dev { enum mlx5_device_state state; /* sync interface state */ struct mutex intf_state_mutex; + struct lock_class_key lock_key; unsigned long intf_state; struct mlx5_priv priv; struct mlx5_profile profile;