commit 0bef512012b1cd8820f0c9ec80e5f8ceb43fdd59 upstream.

Based on a syzbot report, it appears many virtual drivers do not yet use netdev_lockdep_set_classes(), triggerring lockdep false positives.

WARNING: possible recursive locking detected 6.8.0-rc4-next-20240212-syzkaller #0 Not tainted

syz-executor.0/19016 is trying to acquire lock: ffff8880162cb298 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880162cb298 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4452 [inline] ffff8880162cb298 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:340

but task is already holding lock: ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4452 [inline] ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:340

other info that might help us debug this: Possible unsafe locking scenario:

CPU0 lock(_xmit_ETHER#2); lock(_xmit_ETHER#2);

*** DEADLOCK ***

May be due to missing lock nesting notation

9 locks held by syz-executor.0/19016: #0: ffffffff8f385208 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8f385208 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x82c/0x1040 net/core/rtnetlink.c:6603 #1: ffffc90000a08c00 ((&in_dev->mr_ifc_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x600 kernel/time/timer.c:1697 #2: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #2: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #2: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x45f/0x1360 net/ipv4/ip_output.c:228 #3: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #3: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4284 #4: ffff8880416e3258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #4: ffff8880416e3258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #4: ffff8880416e3258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3771 [inline] #4: ffff8880416e3258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1262/0x3b10 net/core/dev.c:4325 #5: ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #5: ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4452 [inline] #5: ffff8880223db4d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:340 #6: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #6: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #6: ffffffff8e131520 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x45f/0x1360 net/ipv4/ip_output.c:228 #7: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #7: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #7: ffffffff8e131580 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4284 #8: ffff888014d9d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #8: ffff888014d9d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #8: ffff888014d9d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3771 [inline] #8: ffff888014d9d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1262/0x3b10 net/core/dev.c:4325

stack backtrace: CPU: 1 PID: 19016 Comm: syz-executor.0 Not tainted 6.8.0-rc4-next-20240212-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4452 [inline] sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3784 [inline] __dev_queue_xmit+0x1912/0x3b10 net/core/dev.c:4325 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xe66/0x1360 net/ipv4/ip_output.c:235 iptunnel_xmit+0x540/0x9b0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x20ee/0x2960 net/ipv4/ip_tunnel.c:831 erspan_xmit+0x9de/0x1460 net/ipv4/ip_gre.c:720 __netdev_start_xmit include/linux/netdevice.h:4989 [inline] netdev_start_xmit include/linux/netdevice.h:5003 [inline] xmit_one net/core/dev.c:3555 [inline] dev_hard_start_xmit+0x242/0x770 net/core/dev.c:3571 sch_direct_xmit+0x2b6/0x5f0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3784 [inline] __dev_queue_xmit+0x1912/0x3b10 net/core/dev.c:4325 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xe66/0x1360 net/ipv4/ip_output.c:235 igmpv3_send_cr net/ipv4/igmp.c:723 [inline] igmp_ifc_timer_expire+0xb71/0xd90 net/ipv4/igmp.c:813 call_timer_fn+0x17e/0x600 kernel/time/timer.c:1700 expire_timers kernel/time/timer.c:1751 [inline] __run_timers+0x621/0x830 kernel/time/timer.c:2038 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2051 __do_softirq+0x2bc/0x943 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1076 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1076 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:resched_offsets_ok kernel/sched/core.c:10127 [inline] RIP: 0010:__might_resched+0x16f/0x780 kernel/sched/core.c:10142 Code: 00 4c 89 e8 48 c1 e8 03 48 ba 00 00 00 00 00 fc ff df 48 89 44 24 38 0f b6 04 10 84 c0 0f 85 87 04 00 00 41 8b 45 00 c1 e0 08 <01> d8 44 39 e0 0f 85 d6 00 00 00 44 89 64 24 1c 48 8d bc 24 a0 00 RSP: 0018:ffffc9000ee069e0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8880296a9e00 RDX: dffffc0000000000 RSI: ffff8880296a9e00 RDI: ffffffff8bfe8fa0 RBP: ffffc9000ee06b00 R08: ffffffff82326877 R09: 1ffff11002b5ad1b R10: dffffc0000000000 R11: ffffed1002b5ad1c R12: 0000000000000000 R13: ffff8880296aa23c R14: 000000000000062a R15: 1ffff92001dc0d44 down_write+0x19/0x50 kernel/locking/rwsem.c:1578 kernfs_activate fs/kernfs/dir.c:1403 [inline] kernfs_add_one+0x4af/0x8b0 fs/kernfs/dir.c:819 __kernfs_create_file+0x22e/0x2e0 fs/kernfs/file.c:1056 sysfs_add_file_mode_ns+0x24a/0x310 fs/sysfs/file.c:307 create_files fs/sysfs/group.c:64 [inline] internal_create_group+0x4f4/0xf20 fs/sysfs/group.c:152 internal_create_groups fs/sysfs/group.c:192 [inline] sysfs_create_groups+0x56/0x120 fs/sysfs/group.c:218 create_dir lib/kobject.c:78 [inline] kobject_add_internal+0x472/0x8d0 lib/kobject.c:240 kobject_add_varg lib/kobject.c:374 [inline] kobject_init_and_add+0x124/0x190 lib/kobject.c:457 netdev_queue_add_kobject net/core/net-sysfs.c:1706 [inline] netdev_queue_update_kobjects+0x1f3/0x480 net/core/net-sysfs.c:1758 register_queue_kobjects net/core/net-sysfs.c:1819 [inline] netdev_register_kobject+0x265/0x310 net/core/net-sysfs.c:2059 register_netdevice+0x1191/0x19c0 net/core/dev.c:10298 bond_newlink+0x3b/0x90 drivers/net/bonding/bond_netlink.c:576 rtnl_newlink_create net/core/rtnetlink.c:3506 [inline] __rtnl_newlink net/core/rtnetlink.c:3726 [inline] rtnl_newlink+0x158f/0x20a0 net/core/rtnetlink.c:3739 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6606 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3c/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 __sys_sendto+0x3a4/0x4f0 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2199 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7fc3fa87fa9c

Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Link: https://lore.kernel.org/r/20240212140700.2795436-4-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sumanth Gavini sumanth.gavini@yahoo.com --- Changes in v2: - With previous patch, Not able to apply on the 6.1 branch. Updated the code changes in 6.1 branch. - Link to v1:https://lore.kernel.org/all/20250724043010.129297-1-sumanth.gavini@yahoo.com... --- drivers/net/dummy.c | 1 + drivers/net/geneve.c | 1 + drivers/net/loopback.c | 1 + drivers/net/veth.c | 1 + drivers/net/vxlan/vxlan_core.c | 1 + net/ipv4/ip_tunnel.c | 1 + net/ipv6/ip6_gre.c | 2 ++ net/ipv6/ip6_tunnel.c | 1 + net/ipv6/ip6_vti.c | 1 + net/ipv6/sit.c | 1 + 10 files changed, 11 insertions(+)

diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c index aa0fc00faecb..f05d4194eb09 100644 --- a/drivers/net/dummy.c +++ b/drivers/net/dummy.c @@ -71,6 +71,7 @@ static int dummy_dev_init(struct net_device *dev) if (!dev->lstats) return -ENOMEM;

+ netdev_lockdep_set_classes(dev); return 0; }

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 3dd5c69b05cb..b31441fc99fc 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -349,6 +349,7 @@ static int geneve_init(struct net_device *dev) gro_cells_destroy(&geneve->gro_cells); return err; } + netdev_lockdep_set_classes(dev); return 0; }

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c index b213397672d2..8dc6a4df93c7 100644 --- a/drivers/net/loopback.c +++ b/drivers/net/loopback.c @@ -144,6 +144,7 @@ static int loopback_dev_init(struct net_device *dev) dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats); if (!dev->lstats) return -ENOMEM; + netdev_lockdep_set_classes(dev); return 0; }

diff --git a/drivers/net/veth.c b/drivers/net/veth.c index e1e7df00e85c..ce90b093bb45 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1373,6 +1373,7 @@ static void veth_free_queues(struct net_device *dev)

static int veth_dev_init(struct net_device *dev) { + netdev_lockdep_set_classes(dev); return veth_alloc_queues(dev); }

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index 747ce00dd321..50dacdc1b6a7 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -2998,6 +2998,7 @@ static int vxlan_init(struct net_device *dev) if (err) goto err_free_percpu;

+ netdev_lockdep_set_classes(dev); return 0;

err_free_percpu: diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index 73d7372afb43..90e55b9979e6 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -1298,6 +1298,7 @@ int ip_tunnel_init(struct net_device *dev)

if (tunnel->collect_md) netif_keep_dst(dev); + netdev_lockdep_set_classes(dev); return 0; } EXPORT_SYMBOL_GPL(ip_tunnel_init); diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index b3e2d658af80..718fcad69cf1 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1537,6 +1537,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev) ip6gre_tnl_init_features(dev);

netdev_hold(dev, &tunnel->dev_tracker, GFP_KERNEL); + netdev_lockdep_set_classes(dev); return 0;

cleanup_dst_cache_init: @@ -1929,6 +1930,7 @@ static int ip6erspan_tap_init(struct net_device *dev) ip6erspan_tnl_link_config(tunnel, 1);

netdev_hold(dev, &tunnel->dev_tracker, GFP_KERNEL); + netdev_lockdep_set_classes(dev); return 0;

cleanup_dst_cache_init: diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index a82d382193e4..2a470c0c38ae 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1902,6 +1902,7 @@ ip6_tnl_dev_init_gen(struct net_device *dev) dev->max_mtu = IP6_MAX_MTU - dev->hard_header_len - t_hlen;

netdev_hold(dev, &t->dev_tracker, GFP_KERNEL); + netdev_lockdep_set_classes(dev); return 0;

destroy_dst: diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index cb71463bbbab..add7276986f1 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -937,6 +937,7 @@ static inline int vti6_dev_init_gen(struct net_device *dev) if (!dev->tstats) return -ENOMEM; netdev_hold(dev, &t->dev_tracker, GFP_KERNEL); + netdev_lockdep_set_classes(dev); return 0; }

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index cc24cefdb85c..eb4c8e2a2b12 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -1460,6 +1460,7 @@ static int ipip6_tunnel_init(struct net_device *dev) return err; } netdev_hold(dev, &tunnel->dev_tracker, GFP_KERNEL); + netdev_lockdep_set_classes(dev); return 0; }