| Message ID | 20190816150654.22106-1-vladbu@mellanox.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] net: flow_offload: convert block_ing_cb_list to regular list type | expand |
On Fri, 16 Aug 2019 18:06:54 +0300, Vlad Buslov wrote: > diff --git a/net/core/flow_offload.c b/net/core/flow_offload.c > index 64c3d4d72b9c..cf52d9c422fa 100644 > --- a/net/core/flow_offload.c > +++ b/net/core/flow_offload.c > @@ -391,6 +391,8 @@ static void flow_indr_block_cb_del(struct flow_indr_block_cb *indr_block_cb) > kfree(indr_block_cb); > } > > +static DEFINE_MUTEX(flow_indr_block_ing_cb_lock); I'd be tempted to place this definition next to: static LIST_HEAD(block_ing_cb_list); as it seems this is the list it protects. The reason for the name discrepancy between the two is not immediately obvious to me :S but you're not changing that. Otherwise makes sense, so FWIW: Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> > static void flow_block_ing_cmd(struct net_device *dev, > flow_indr_block_bind_cb_t *cb, > void *cb_priv, > @@ -398,11 +400,11 @@ static void flow_block_ing_cmd(struct net_device *dev, > { > struct flow_indr_block_ing_entry *entry; > > - rcu_read_lock(); > - list_for_each_entry_rcu(entry, &block_ing_cb_list, list) { > + mutex_lock(&flow_indr_block_ing_cb_lock); > + list_for_each_entry(entry, &block_ing_cb_list, list) { > entry->cb(dev, cb, cb_priv, command); > } > - rcu_read_unlock(); > + mutex_unlock(&flow_indr_block_ing_cb_lock); > }
Fri, Aug 16, 2019 at 05:06:54PM CEST, vladbu@mellanox.com wrote: >RCU list block_ing_cb_list is protected by rcu read lock in >flow_block_ing_cmd() and with flow_indr_block_ing_cb_lock mutex in all >functions that use it. However, flow_block_ing_cmd() needs to call blocking >functions while iterating block_ing_cb_list which leads to following >suspicious RCU usage warning: > >[ 401.510948] ============================= >[ 401.510952] WARNING: suspicious RCU usage >[ 401.510993] 5.3.0-rc3+ #589 Not tainted >[ 401.510996] ----------------------------- >[ 401.511001] include/linux/rcupdate.h:265 Illegal context switch in RCU read-side critical section! >[ 401.511004] > other info that might help us debug this: > >[ 401.511008] > rcu_scheduler_active = 2, debug_locks = 1 >[ 401.511012] 7 locks held by test-ecmp-add-v/7576: >[ 401.511015] #0: 00000000081d71a5 (sb_writers#4){.+.+}, at: vfs_write+0x166/0x1d0 >[ 401.511037] #1: 000000002bd338c3 (&of->mutex){+.+.}, at: kernfs_fop_write+0xef/0x1b0 >[ 401.511051] #2: 00000000c921c634 (kn->count#317){.+.+}, at: kernfs_fop_write+0xf7/0x1b0 >[ 401.511062] #3: 00000000a19cdd56 (&dev->mutex){....}, at: sriov_numvfs_store+0x6b/0x130 >[ 401.511079] #4: 000000005425fa52 (pernet_ops_rwsem){++++}, at: unregister_netdevice_notifier+0x30/0x140 >[ 401.511092] #5: 00000000c5822793 (rtnl_mutex){+.+.}, at: unregister_netdevice_notifier+0x35/0x140 >[ 401.511101] #6: 00000000c2f3507e (rcu_read_lock){....}, at: flow_block_ing_cmd+0x5/0x130 >[ 401.511115] > stack backtrace: >[ 401.511121] CPU: 21 PID: 7576 Comm: test-ecmp-add-v Not tainted 5.3.0-rc3+ #589 >[ 401.511124] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017 >[ 401.511127] Call Trace: >[ 401.511138] dump_stack+0x85/0xc0 >[ 401.511146] ___might_sleep+0x100/0x180 >[ 401.511154] __mutex_lock+0x5b/0x960 >[ 401.511162] ? find_held_lock+0x2b/0x80 >[ 401.511173] ? __tcf_get_next_chain+0x1d/0xb0 >[ 401.511179] ? mark_held_locks+0x49/0x70 >[ 401.511194] ? __tcf_get_next_chain+0x1d/0xb0 >[ 401.511198] __tcf_get_next_chain+0x1d/0xb0 >[ 401.511251] ? uplink_rep_async_event+0x70/0x70 [mlx5_core] >[ 401.511261] tcf_block_playback_offloads+0x39/0x160 >[ 401.511276] tcf_block_setup+0x1b0/0x240 >[ 401.511312] ? mlx5e_rep_indr_setup_tc_cb+0xca/0x290 [mlx5_core] >[ 401.511347] ? mlx5e_rep_indr_tc_block_unbind+0x50/0x50 [mlx5_core] >[ 401.511359] tc_indr_block_get_and_ing_cmd+0x11b/0x1e0 >[ 401.511404] ? mlx5e_rep_indr_tc_block_unbind+0x50/0x50 [mlx5_core] >[ 401.511414] flow_block_ing_cmd+0x7e/0x130 >[ 401.511453] ? mlx5e_rep_indr_tc_block_unbind+0x50/0x50 [mlx5_core] >[ 401.511462] __flow_indr_block_cb_unregister+0x7f/0xf0 >[ 401.511502] mlx5e_nic_rep_netdevice_event+0x75/0xb0 [mlx5_core] >[ 401.511513] unregister_netdevice_notifier+0xe9/0x140 >[ 401.511554] mlx5e_cleanup_rep_tx+0x6f/0xe0 [mlx5_core] >[ 401.511597] mlx5e_detach_netdev+0x4b/0x60 [mlx5_core] >[ 401.511637] mlx5e_vport_rep_unload+0x71/0xc0 [mlx5_core] >[ 401.511679] esw_offloads_disable+0x5b/0x90 [mlx5_core] >[ 401.511724] mlx5_eswitch_disable.cold+0xdf/0x176 [mlx5_core] >[ 401.511759] mlx5_device_disable_sriov+0xab/0xb0 [mlx5_core] >[ 401.511794] mlx5_core_sriov_configure+0xaf/0xd0 [mlx5_core] >[ 401.511805] sriov_numvfs_store+0xf8/0x130 >[ 401.511817] kernfs_fop_write+0x122/0x1b0 >[ 401.511826] vfs_write+0xdb/0x1d0 >[ 401.511835] ksys_write+0x65/0xe0 >[ 401.511847] do_syscall_64+0x5c/0xb0 >[ 401.511857] entry_SYSCALL_64_after_hwframe+0x49/0xbe >[ 401.511862] RIP: 0033:0x7fad892d30f8 >[ 401.511868] Code: 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 96 0d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 60 c3 0f 1f 80 00 00 00 00 48 83 > ec 28 48 89 >[ 401.511871] RSP: 002b:00007ffca2a9fad8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 >[ 401.511875] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fad892d30f8 >[ 401.511878] RDX: 0000000000000002 RSI: 000055afeb072a90 RDI: 0000000000000001 >[ 401.511881] RBP: 000055afeb072a90 R08: 00000000ffffffff R09: 000000000000000a >[ 401.511884] R10: 000055afeb058710 R11: 0000000000000246 R12: 0000000000000002 >[ 401.511887] R13: 00007fad893a8780 R14: 0000000000000002 R15: 00007fad893a3740 > >To fix the described incorrect RCU usage, convert block_ing_cb_list from >RCU list to regular list and protect it with flow_indr_block_ing_cb_lock >mutex in flow_block_ing_cmd(). > >Fixes: 1150ab0f1b33 ("flow_offload: support get multi-subsystem block") >Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com>
From: Vlad Buslov <vladbu@mellanox.com> Date: Fri, 16 Aug 2019 18:06:54 +0300 > RCU list block_ing_cb_list is protected by rcu read lock in > flow_block_ing_cmd() and with flow_indr_block_ing_cb_lock mutex in all > functions that use it. However, flow_block_ing_cmd() needs to call blocking > functions while iterating block_ing_cb_list which leads to following > suspicious RCU usage warning: ... > To fix the described incorrect RCU usage, convert block_ing_cb_list from > RCU list to regular list and protect it with flow_indr_block_ing_cb_lock > mutex in flow_block_ing_cmd(). > > Fixes: 1150ab0f1b33 ("flow_offload: support get multi-subsystem block") > Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Applied.
diff --git a/net/core/flow_offload.c b/net/core/flow_offload.c index 64c3d4d72b9c..cf52d9c422fa 100644 --- a/net/core/flow_offload.c +++ b/net/core/flow_offload.c @@ -391,6 +391,8 @@ static void flow_indr_block_cb_del(struct flow_indr_block_cb *indr_block_cb) kfree(indr_block_cb); } +static DEFINE_MUTEX(flow_indr_block_ing_cb_lock); + static void flow_block_ing_cmd(struct net_device *dev, flow_indr_block_bind_cb_t *cb, void *cb_priv, @@ -398,11 +400,11 @@ static void flow_block_ing_cmd(struct net_device *dev, { struct flow_indr_block_ing_entry *entry; - rcu_read_lock(); - list_for_each_entry_rcu(entry, &block_ing_cb_list, list) { + mutex_lock(&flow_indr_block_ing_cb_lock); + list_for_each_entry(entry, &block_ing_cb_list, list) { entry->cb(dev, cb, cb_priv, command); } - rcu_read_unlock(); + mutex_unlock(&flow_indr_block_ing_cb_lock); } int __flow_indr_block_cb_register(struct net_device *dev, void *cb_priv, @@ -497,11 +499,10 @@ void flow_indr_block_call(struct net_device *dev, } EXPORT_SYMBOL_GPL(flow_indr_block_call); -static DEFINE_MUTEX(flow_indr_block_ing_cb_lock); void flow_indr_add_block_ing_cb(struct flow_indr_block_ing_entry *entry) { mutex_lock(&flow_indr_block_ing_cb_lock); - list_add_tail_rcu(&entry->list, &block_ing_cb_list); + list_add_tail(&entry->list, &block_ing_cb_list); mutex_unlock(&flow_indr_block_ing_cb_lock); } EXPORT_SYMBOL_GPL(flow_indr_add_block_ing_cb); @@ -509,7 +510,7 @@ EXPORT_SYMBOL_GPL(flow_indr_add_block_ing_cb); void flow_indr_del_block_ing_cb(struct flow_indr_block_ing_entry *entry) { mutex_lock(&flow_indr_block_ing_cb_lock); - list_del_rcu(&entry->list); + list_del(&entry->list); mutex_unlock(&flow_indr_block_ing_cb_lock); } EXPORT_SYMBOL_GPL(flow_indr_del_block_ing_cb);
RCU list block_ing_cb_list is protected by rcu read lock in flow_block_ing_cmd() and with flow_indr_block_ing_cb_lock mutex in all functions that use it. However, flow_block_ing_cmd() needs to call blocking functions while iterating block_ing_cb_list which leads to following suspicious RCU usage warning: [ 401.510948] ============================= [ 401.510952] WARNING: suspicious RCU usage [ 401.510993] 5.3.0-rc3+ #589 Not tainted [ 401.510996] ----------------------------- [ 401.511001] include/linux/rcupdate.h:265 Illegal context switch in RCU read-side critical section! [ 401.511004] other info that might help us debug this: [ 401.511008] rcu_scheduler_active = 2, debug_locks = 1 [ 401.511012] 7 locks held by test-ecmp-add-v/7576: [ 401.511015] #0: 00000000081d71a5 (sb_writers#4){.+.+}, at: vfs_write+0x166/0x1d0 [ 401.511037] #1: 000000002bd338c3 (&of->mutex){+.+.}, at: kernfs_fop_write+0xef/0x1b0 [ 401.511051] #2: 00000000c921c634 (kn->count#317){.+.+}, at: kernfs_fop_write+0xf7/0x1b0 [ 401.511062] #3: 00000000a19cdd56 (&dev->mutex){....}, at: sriov_numvfs_store+0x6b/0x130 [ 401.511079] #4: 000000005425fa52 (pernet_ops_rwsem){++++}, at: unregister_netdevice_notifier+0x30/0x140 [ 401.511092] #5: 00000000c5822793 (rtnl_mutex){+.+.}, at: unregister_netdevice_notifier+0x35/0x140 [ 401.511101] #6: 00000000c2f3507e (rcu_read_lock){....}, at: flow_block_ing_cmd+0x5/0x130 [ 401.511115] stack backtrace: [ 401.511121] CPU: 21 PID: 7576 Comm: test-ecmp-add-v Not tainted 5.3.0-rc3+ #589 [ 401.511124] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017 [ 401.511127] Call Trace: [ 401.511138] dump_stack+0x85/0xc0 [ 401.511146] ___might_sleep+0x100/0x180 [ 401.511154] __mutex_lock+0x5b/0x960 [ 401.511162] ? find_held_lock+0x2b/0x80 [ 401.511173] ? __tcf_get_next_chain+0x1d/0xb0 [ 401.511179] ? mark_held_locks+0x49/0x70 [ 401.511194] ? __tcf_get_next_chain+0x1d/0xb0 [ 401.511198] __tcf_get_next_chain+0x1d/0xb0 [ 401.511251] ? uplink_rep_async_event+0x70/0x70 [mlx5_core] [ 401.511261] tcf_block_playback_offloads+0x39/0x160 [ 401.511276] tcf_block_setup+0x1b0/0x240 [ 401.511312] ? mlx5e_rep_indr_setup_tc_cb+0xca/0x290 [mlx5_core] [ 401.511347] ? mlx5e_rep_indr_tc_block_unbind+0x50/0x50 [mlx5_core] [ 401.511359] tc_indr_block_get_and_ing_cmd+0x11b/0x1e0 [ 401.511404] ? mlx5e_rep_indr_tc_block_unbind+0x50/0x50 [mlx5_core] [ 401.511414] flow_block_ing_cmd+0x7e/0x130 [ 401.511453] ? mlx5e_rep_indr_tc_block_unbind+0x50/0x50 [mlx5_core] [ 401.511462] __flow_indr_block_cb_unregister+0x7f/0xf0 [ 401.511502] mlx5e_nic_rep_netdevice_event+0x75/0xb0 [mlx5_core] [ 401.511513] unregister_netdevice_notifier+0xe9/0x140 [ 401.511554] mlx5e_cleanup_rep_tx+0x6f/0xe0 [mlx5_core] [ 401.511597] mlx5e_detach_netdev+0x4b/0x60 [mlx5_core] [ 401.511637] mlx5e_vport_rep_unload+0x71/0xc0 [mlx5_core] [ 401.511679] esw_offloads_disable+0x5b/0x90 [mlx5_core] [ 401.511724] mlx5_eswitch_disable.cold+0xdf/0x176 [mlx5_core] [ 401.511759] mlx5_device_disable_sriov+0xab/0xb0 [mlx5_core] [ 401.511794] mlx5_core_sriov_configure+0xaf/0xd0 [mlx5_core] [ 401.511805] sriov_numvfs_store+0xf8/0x130 [ 401.511817] kernfs_fop_write+0x122/0x1b0 [ 401.511826] vfs_write+0xdb/0x1d0 [ 401.511835] ksys_write+0x65/0xe0 [ 401.511847] do_syscall_64+0x5c/0xb0 [ 401.511857] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 401.511862] RIP: 0033:0x7fad892d30f8 [ 401.511868] Code: 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 96 0d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 60 c3 0f 1f 80 00 00 00 00 48 83 ec 28 48 89 [ 401.511871] RSP: 002b:00007ffca2a9fad8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 401.511875] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fad892d30f8 [ 401.511878] RDX: 0000000000000002 RSI: 000055afeb072a90 RDI: 0000000000000001 [ 401.511881] RBP: 000055afeb072a90 R08: 00000000ffffffff R09: 000000000000000a [ 401.511884] R10: 000055afeb058710 R11: 0000000000000246 R12: 0000000000000002 [ 401.511887] R13: 00007fad893a8780 R14: 0000000000000002 R15: 00007fad893a3740 To fix the described incorrect RCU usage, convert block_ing_cb_list from RCU list to regular list and protect it with flow_indr_block_ing_cb_lock mutex in flow_block_ing_cmd(). Fixes: 1150ab0f1b33 ("flow_offload: support get multi-subsystem block") Signed-off-by: Vlad Buslov <vladbu@mellanox.com> --- net/core/flow_offload.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)