====================================================== WARNING: possible circular locking dependency detected 6.1.111-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.743/6564 is trying to acquire lock: ffff8880b8f28118 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2991 [inline] ffff8880b8f28118 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline] ffff8880b8f28118 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x1b2/0x8c0 kernel/rcu/tree.c:3402 but task is already holding lock: ffff8880b8f28358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&base->lock){-.-.}-{2:2}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 lock_timer_base+0x120/0x260 kernel/time/timer.c:999 __mod_timer+0x1cb/0xee0 kernel/time/timer.c:1072 queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1704 queue_delayed_work include/linux/workqueue.h:527 [inline] schedule_delayed_monitor_work kernel/rcu/tree.c:3172 [inline] kvfree_call_rcu+0x520/0x8c0 kernel/rcu/tree.c:3428 rtnl_register_internal+0x489/0x580 net/core/rtnetlink.c:260 rtnl_register+0x32/0x70 net/core/rtnetlink.c:310 ip_rt_init+0x335/0x3c7 net/ipv4/route.c:3763 ip_init+0xa/0x14 net/ipv4/ip_output.c:1767 inet_init+0x2ae/0x3c0 net/ipv4/af_inet.c:2035 do_one_initcall+0x265/0x8f0 init/main.c:1298 do_initcall_level+0x157/0x207 init/main.c:1371 do_initcalls+0x49/0x86 init/main.c:1387 kernel_init_freeable+0x45c/0x60f init/main.c:1626 kernel_init+0x19/0x290 init/main.c:1514 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #0 (krc.lock){..-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:2991 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline] kvfree_call_rcu+0x1b2/0x8c0 kernel/rcu/tree.c:3402 trie_delete_elem+0x53a/0x690 kernel/bpf/lpm_trie.c:532 bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline] bpf_trace_run3+0x231/0x440 kernel/trace/bpf_trace.c:2313 trace_timer_start include/trace/events/timer.h:53 [inline] enqueue_timer+0x440/0x600 kernel/time/timer.c:609 __mod_timer+0x92b/0xee0 mrp_join_timer_arm net/802/mrp.c:596 [inline] mrp_join_timer+0x144/0x180 net/802/mrp.c:611 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1820 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571 __do_softirq kernel/softirq.c:605 [inline] invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:654 irq_exit_rcu+0x5/0x20 kernel/softirq.c:666 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653 rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] rcu_is_watching+0x18/0xb0 kernel/rcu/tree.c:721 rcu_read_unlock include/linux/rcupdate.h:820 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:337 [inline] percpu_ref_put+0x8e/0x100 include/linux/percpu-refcount.h:351 slab_alloc_node mm/slub.c:3398 [inline] __kmem_cache_alloc_node+0x137/0x260 mm/slub.c:3437 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:557 [inline] kzalloc include/linux/slab.h:693 [inline] bpf_prog_alloc_no_stats+0xb0/0x3f0 kernel/bpf/core.c:96 bpf_prog_alloc+0x1c/0x1b0 kernel/bpf/core.c:130 bpf_prog_load+0x803/0x1bb0 kernel/bpf/syscall.c:2592 __sys_bpf+0x382/0x6c0 kernel/bpf/syscall.c:5020 __do_sys_bpf kernel/bpf/syscall.c:5124 [inline] __se_sys_bpf kernel/bpf/syscall.c:5122 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5122 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 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 *** 5 locks held by syz.3.743/6564: #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: percpu_ref_put_many include/linux/percpu-refcount.h:330 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: percpu_ref_put+0x12/0x100 include/linux/percpu-refcount.h:351 #1: ffffc900001e0bc0 ((&app->join_timer)#2){+.-.}-{0:0}, at: call_timer_fn+0xc2/0x6b0 kernel/time/timer.c:1501 #2: ffff888068b5b4c8 (&app->lock#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #2: ffff888068b5b4c8 (&app->lock#2){+.-.}-{2:2}, at: mrp_join_timer+0xca/0x180 net/802/mrp.c:609 #3: ffff8880b8f28358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999 #4: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #4: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #4: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2272 [inline] #4: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x146/0x440 kernel/trace/bpf_trace.c:2313 stack backtrace: CPU: 1 PID: 6564 Comm: syz.3.743 Not tainted 6.1.111-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:2991 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline] kvfree_call_rcu+0x1b2/0x8c0 kernel/rcu/tree.c:3402 trie_delete_elem+0x53a/0x690 kernel/bpf/lpm_trie.c:532 bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline] bpf_trace_run3+0x231/0x440 kernel/trace/bpf_trace.c:2313 trace_timer_start include/trace/events/timer.h:53 [inline] enqueue_timer+0x440/0x600 kernel/time/timer.c:609 __mod_timer+0x92b/0xee0 mrp_join_timer_arm net/802/mrp.c:596 [inline] mrp_join_timer+0x144/0x180 net/802/mrp.c:611 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1504 expire_timers kernel/time/timer.c:1549 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1820 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571 __do_softirq kernel/softirq.c:605 [inline] invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:654 irq_exit_rcu+0x5/0x20 kernel/softirq.c:666 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653 RIP: 0010:rcu_is_watching+0x18/0xb0 kernel/rcu/tree.c:721 Code: 4c 89 f6 e8 1a 48 f1 02 e9 2b ff ff ff e8 60 72 33 09 41 57 41 56 53 65 ff 05 4c 06 8f 7e e8 9f 8a 33 09 89 c3 83 f8 08 73 76 <49> bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 70 b8 d8 8c 4c 89 f0 48 RSP: 0018:ffffc9000322fa60 EFLAGS: 00000297 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffff888051ef3b80 RDX: dffffc0000000000 RSI: ffffffff8b5d6da0 RDI: ffffffff8b5d6d60 RBP: 0000000000000518 R08: dffffc0000000000 R09: fffffbfff223b845 R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888017c4c140 R13: 00000000ffffffff R14: ffff88801febe480 R15: ffff8880769d0000 rcu_read_unlock include/linux/rcupdate.h:820 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:337 [inline] percpu_ref_put+0x8e/0x100 include/linux/percpu-refcount.h:351 slab_alloc_node mm/slub.c:3398 [inline] __kmem_cache_alloc_node+0x137/0x260 mm/slub.c:3437 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:557 [inline] kzalloc include/linux/slab.h:693 [inline] bpf_prog_alloc_no_stats+0xb0/0x3f0 kernel/bpf/core.c:96 bpf_prog_alloc+0x1c/0x1b0 kernel/bpf/core.c:130 bpf_prog_load+0x803/0x1bb0 kernel/bpf/syscall.c:2592 __sys_bpf+0x382/0x6c0 kernel/bpf/syscall.c:5020 __do_sys_bpf kernel/bpf/syscall.c:5124 [inline] __se_sys_bpf kernel/bpf/syscall.c:5122 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5122 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8b7f57df39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8b80414038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f8b7f735f80 RCX: 00007f8b7f57df39 RDX: 0000000000000090 RSI: 00000000200007c0 RDI: 0000000000000005 RBP: 00007f8b7f5f0216 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f8b7f735f80 R15: 00007ffeed051618 ---------------- Code disassembly (best guess): 0: 4c 89 f6 mov %r14,%rsi 3: e8 1a 48 f1 02 call 0x2f14822 8: e9 2b ff ff ff jmp 0xffffff38 d: e8 60 72 33 09 call 0x9337272 12: 41 57 push %r15 14: 41 56 push %r14 16: 53 push %rbx 17: 65 ff 05 4c 06 8f 7e incl %gs:0x7e8f064c(%rip) # 0x7e8f066a 1e: e8 9f 8a 33 09 call 0x9338ac2 23: 89 c3 mov %eax,%ebx 25: 83 f8 08 cmp $0x8,%eax 28: 73 76 jae 0xa0 * 2a: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15 <-- trapping instruction 31: fc ff df 34: 4c 8d 34 dd 70 b8 d8 lea -0x73274790(,%rbx,8),%r14 3b: 8c 3c: 4c 89 f0 mov %r14,%rax 3f: 48 rex.W