====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc6-syzkaller-01468-g173e7622ccb3 #0 Not tainted ------------------------------------------------------ sshd/5077 is trying to acquire lock: ffff8880b9529430 (krc.lock){....}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2960 [inline] ffff8880b9529430 (krc.lock){....}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3359 [inline] ffff8880b9529430 (krc.lock){....}-{2:2}, at: kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3444 but task is already holding lock: ffff8880b952a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1052 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:5754 __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:1052 __mod_timer+0x1ca/0xeb0 kernel/time/timer.c:1133 queue_delayed_work_on+0x15a/0x260 kernel/workqueue.c:2608 kvfree_call_rcu+0x47f/0x790 kernel/rcu/tree.c:3472 rtnl_register_internal+0x482/0x590 net/core/rtnetlink.c:265 rtnl_register+0x36/0x80 net/core/rtnetlink.c:315 ip_rt_init+0x2f5/0x3a0 net/ipv4/route.c:3702 ip_init+0xe/0x20 net/ipv4/ip_output.c:1663 inet_init+0x3d8/0x580 net/ipv4/af_inet.c:2024 do_one_initcall+0x248/0x880 init/main.c:1245 do_initcall_level+0x157/0x210 init/main.c:1307 do_initcalls+0x3f/0x80 init/main.c:1323 kernel_init_freeable+0x435/0x5d0 init/main.c:1555 kernel_init+0x1d/0x2b0 init/main.c:1444 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 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:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 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 krc_this_cpu_lock kernel/rcu/tree.c:2960 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3359 [inline] kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3444 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:2392 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2433 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ce/0x570 kernel/time/timer.c:664 __mod_timer+0x953/0xeb0 kernel/time/timer.c:1182 sk_reset_timer+0x23/0xc0 net/core/sock.c:3419 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:234 [inline] tcp_reset_xmit_timer include/net/tcp.h:1418 [inline] tcp_schedule_loss_probe+0x419/0x560 net/ipv4/tcp_output.c:2911 tcp_write_xmit+0x42c9/0x69d0 net/ipv4/tcp_output.c:2860 __tcp_push_pending_frames+0x9b/0x360 net/ipv4/tcp_output.c:3014 tcp_sendmsg_locked+0x4313/0x4d70 net/ipv4/tcp.c:1316 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1348 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 call_write_iter include/linux/fs.h:2110 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa84/0xcb0 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+0xf5/0x240 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/5077: #0: ffff88804f419ad8 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1595 [inline] #0: ffff88804f419ad8 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_sendmsg+0x22/0x50 net/ipv4/tcp.c:1347 #1: ffff8880b952a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1052 #2: ffffffff8e334ea0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #2: ffffffff8e334ea0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #2: ffffffff8e334ea0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2391 [inline] #2: ffffffff8e334ea0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2433 stack backtrace: CPU: 1 PID: 5077 Comm: sshd Not tainted 6.9.0-rc6-syzkaller-01468-g173e7622ccb3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 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 krc_this_cpu_lock kernel/rcu/tree.c:2960 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3359 [inline] kvfree_call_rcu+0x18a/0x790 kernel/rcu/tree.c:3444 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:2392 [inline] bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2433 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ce/0x570 kernel/time/timer.c:664 __mod_timer+0x953/0xeb0 kernel/time/timer.c:1182 sk_reset_timer+0x23/0xc0 net/core/sock.c:3419 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:234 [inline] tcp_reset_xmit_timer include/net/tcp.h:1418 [inline] tcp_schedule_loss_probe+0x419/0x560 net/ipv4/tcp_output.c:2911 tcp_write_xmit+0x42c9/0x69d0 net/ipv4/tcp_output.c:2860 __tcp_push_pending_frames+0x9b/0x360 net/ipv4/tcp_output.c:3014 tcp_sendmsg_locked+0x4313/0x4d70 net/ipv4/tcp.c:1316 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1348 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 call_write_iter include/linux/fs.h:2110 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa84/0xcb0 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+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc15f516bf2 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:00007ffd21172e38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007fc15f516bf2 RDX: 000000000000002c RSI: 0000562a15270960 RDI: 0000000000000004 RBP: 0000562a1527e220 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00005629f805daa4 R13: 0000000000000039 R14: 00005629f805e3e8 R15: 00007ffd21172ea8