====================================================== WARNING: possible circular locking dependency detected 6.10.0-rc2-next-20240606-syzkaller #0 Tainted: G W ------------------------------------------------------ sshd/5090 is trying to acquire lock: ffff8880b9429430 (krc.lock){....}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3327 [inline] ffff8880b9429430 (krc.lock){....}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3726 [inline] ffff8880b9429430 (krc.lock){....}-{2:2}, at: kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3811 but task is already holding lock: ffff8880b942a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&base->lock){-.-.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5817 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 lock_timer_base+0x112/0x240 kernel/time/timer.c:1051 __mod_timer+0x1ca/0xeb0 kernel/time/timer.c:1132 queue_delayed_work_on+0x1ca/0x390 kernel/workqueue.c:2573 kvfree_call_rcu+0x47f/0x790 kernel/rcu/tree.c:3839 rtnl_register_internal+0x482/0x590 net/core/rtnetlink.c:265 rtnl_register+0x36/0x80 net/core/rtnetlink.c:315 ip_rt_init+0x2f6/0x3a0 net/ipv4/route.c:3696 ip_init+0xe/0x20 net/ipv4/ip_output.c:1667 inet_init+0x3d8/0x580 net/ipv4/af_inet.c:1983 do_one_initcall+0x248/0x880 init/main.c:1267 do_initcall_level+0x157/0x210 init/main.c:1329 do_initcalls+0x3f/0x80 init/main.c:1345 kernel_init_freeable+0x435/0x5d0 init/main.c:1578 kernel_init+0x1d/0x2b0 init/main.c:1467 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (krc.lock){....}-{2:2}: check_prev_add kernel/locking/lockdep.c:3159 [inline] check_prevs_add kernel/locking/lockdep.c:3278 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3902 __lock_acquire+0x1359/0x2000 kernel/locking/lockdep.c:5194 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5817 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:3327 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3726 [inline] kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3811 trie_delete_elem+0x546/0x6a0 kernel/bpf/lpm_trie.c:540 bpf_prog_2c29ac5cdc6b1842+0x42/0x46 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2444 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ce/0x570 kernel/time/timer.c:663 __mod_timer+0x953/0xeb0 kernel/time/timer.c:1181 sk_reset_timer+0x23/0xc0 net/core/sock.c:3440 tcp_event_new_data_sent+0x203/0x360 net/ipv4/tcp_output.c:83 tcp_write_xmit+0x18dc/0x6a10 net/ipv4/tcp_output.c:2836 __tcp_push_pending_frames+0x9b/0x360 net/ipv4/tcp_output.c:3014 tcp_sendmsg_locked+0x43b1/0x4e10 net/ipv4/tcp.c:1321 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1353 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 sock_write_iter+0x2dd/0x400 net/socket.c:1160 new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa72/0xc90 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&base->lock); lock(krc.lock); lock(&base->lock); lock(krc.lock); *** DEADLOCK *** 3 locks held by sshd/5090: #0: ffff88802d653358 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1602 [inline] #0: ffff88802d653358 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_sendmsg+0x22/0x50 net/ipv4/tcp.c:1352 #1: ffff8880b942a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051 #2: ffffffff8e334520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #2: ffffffff8e334520 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #2: ffffffff8e334520 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2402 [inline] #2: ffffffff8e334520 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2444 stack backtrace: CPU: 0 PID: 5090 Comm: sshd Tainted: G W 6.10.0-rc2-next-20240606-syzkaller #0 Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: __dump_stack lib/dump_stack.c:91 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:117 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2075 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2204 check_prev_add kernel/locking/lockdep.c:3159 [inline] check_prevs_add kernel/locking/lockdep.c:3278 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3902 __lock_acquire+0x1359/0x2000 kernel/locking/lockdep.c:5194 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5817 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:3327 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3726 [inline] kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3811 trie_delete_elem+0x546/0x6a0 kernel/bpf/lpm_trie.c:540 bpf_prog_2c29ac5cdc6b1842+0x42/0x46 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2444 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ce/0x570 kernel/time/timer.c:663 __mod_timer+0x953/0xeb0 kernel/time/timer.c:1181 sk_reset_timer+0x23/0xc0 net/core/sock.c:3440 tcp_event_new_data_sent+0x203/0x360 net/ipv4/tcp_output.c:83 tcp_write_xmit+0x18dc/0x6a10 net/ipv4/tcp_output.c:2836 __tcp_push_pending_frames+0x9b/0x360 net/ipv4/tcp_output.c:3014 tcp_sendmsg_locked+0x43b1/0x4e10 net/ipv4/tcp.c:1321 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1353 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 sock_write_iter+0x2dd/0x400 net/socket.c:1160 new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa72/0xc90 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc1e8b16bf2 Code: 89 c7 48 89 44 24 08 e8 7b 34 fa ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6f 48 8b 15 07 a2 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffe5bd48cd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007fc1e8b16bf2 RDX: 000000000000002c RSI: 0000563611ace960 RDI: 0000000000000004 RBP: 0000563611ad73f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00005635e7499aa4 R13: 0000000000000046 R14: 00005635e749a3e8 R15: 00007ffe5bd48d48