====================================================== WARNING: possible circular locking dependency detected 6.1.141-syzkaller #0 Not tainted ------------------------------------------------------ syz.5.1613/9059 is trying to acquire lock: ffff8880b8e281d8 (krc.lock){-.-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:2991 [inline] ffff8880b8e281d8 (krc.lock){-.-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3311 [inline] ffff8880b8e281d8 (krc.lock){-.-.}-{2:2}, at: kvfree_call_rcu+0x184/0x870 kernel/rcu/tree.c:3402 but task is already holding lock: ffff8880b8e2a598 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1756 [inline] ffff8880b8e2a598 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x63a/0xd60 kernel/time/hrtimer.c:1816 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (hrtimer_bases.lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 lock_hrtimer_base kernel/time/hrtimer.c:180 [inline] hrtimer_start_range_ns+0xec/0xfc0 kernel/time/hrtimer.c:1351 hrtimer_start include/linux/hrtimer.h:421 [inline] run_page_cache_worker kernel/rcu/tree.c:3293 [inline] kvfree_call_rcu+0x6d0/0x870 kernel/rcu/tree.c:3404 rtnl_register_internal+0x489/0x590 net/core/rtnetlink.c:260 rtnl_register+0x2e/0x70 net/core/rtnetlink.c:310 ip_rt_init+0x323/0x3b5 net/ipv4/route.c:3789 ip_init+0xa/0x14 net/ipv4/ip_output.c:1771 inet_init+0x2bd/0x3cf net/ipv4/af_inet.c:2033 do_one_initcall+0x214/0x7a0 init/main.c:1298 do_initcall_level+0x137/0x1e4 init/main.c:1371 do_initcalls+0x4b/0x8a init/main.c:1387 kernel_init_freeable+0x3fa/0x5ac init/main.c:1626 kernel_init+0x19/0x1b0 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 kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 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+0x184/0x870 kernel/rcu/tree.c:3402 trie_delete_elem+0x52d/0x690 kernel/bpf/lpm_trie.c:545 bpf_prog_9f8b072885af44f0+0x42/0x46 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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:2285 [inline] bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 trace_hrtimer_start include/trace/events/timer.h:202 [inline] debug_activate kernel/time/hrtimer.c:504 [inline] enqueue_hrtimer+0x36e/0x3f0 kernel/time/hrtimer.c:1110 __run_hrtimer kernel/time/hrtimer.c:1769 [inline] __hrtimer_run_queues+0x68e/0xd60 kernel/time/hrtimer.c:1816 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1878 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 stack_trace_consume_entry+0x0/0x270 arch_stack_walk+0x100/0x140 arch/x86/kernel/stacktrace.c:27 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc_node_track_caller+0xae/0x230 mm/slab_common.c:956 __do_krealloc mm/slab_common.c:1336 [inline] krealloc+0x6a/0x100 mm/slab_common.c:1369 push_jmp_history kernel/bpf/verifier.c:2479 [inline] is_state_visited kernel/bpf/verifier.c:12311 [inline] do_check kernel/bpf/verifier.c:12451 [inline] do_check_common+0x41bd/0xc6a0 kernel/bpf/verifier.c:14933 do_check_main kernel/bpf/verifier.c:14996 [inline] bpf_check+0x3ee1/0x10ca0 kernel/bpf/verifier.c:15573 bpf_prog_load+0x1072/0x15a0 kernel/bpf/syscall.c:2641 __sys_bpf+0x520/0x6d0 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+0x4c/0xa0 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(hrtimer_bases.lock); lock(krc.lock); lock(hrtimer_bases.lock); lock(krc.lock); *** DEADLOCK *** 2 locks held by syz.5.1613/9059: #0: ffff8880b8e2a598 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1756 [inline] #0: ffff8880b8e2a598 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x63a/0xd60 kernel/time/hrtimer.c:1816 #1: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] #1: ffffffff8c92aaa0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324 stack backtrace: CPU: 0 PID: 9059 Comm: syz.5.1613 Not tainted 6.1.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 check_noncircular+0x274/0x310 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 kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 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+0x184/0x870 kernel/rcu/tree.c:3402 trie_delete_elem+0x52d/0x690 kernel/bpf/lpm_trie.c:545 bpf_prog_9f8b072885af44f0+0x42/0x46 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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:2285 [inline] bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 trace_hrtimer_start include/trace/events/timer.h:202 [inline] debug_activate kernel/time/hrtimer.c:504 [inline] enqueue_hrtimer+0x36e/0x3f0 kernel/time/hrtimer.c:1110 __run_hrtimer kernel/time/hrtimer.c:1769 [inline] __hrtimer_run_queues+0x68e/0xd60 kernel/time/hrtimer.c:1816 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1878 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:stack_trace_consume_entry+0x0/0x270 kernel/stacktrace.c:83 Code: 48 8b 0c 25 28 00 00 00 48 3b 4c 24 78 75 09 48 8d 65 f0 5b 41 5e 5d c3 e8 fd e2 9f 08 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 <55> 41 57 41 56 41 55 41 54 53 48 83 ec 18 48 ba 00 00 00 00 00 fc RSP: 0018:ffffc900032eed20 EFLAGS: 00000286 RAX: ffffffff81d2262b RBX: ffffc900032eede0 RCX: 0000000080000000 RDX: ffffc900032eed01 RSI: ffffffff81d2262b RDI: ffffc900032eede0 RBP: ffffc900032eedb0 R08: ffffc900032eee60 R09: ffffc900032eed78 R10: fffff5200065ddb1 R11: 1ffff9200065ddaf R12: ffff88802bdd5940 R13: 0000000000000000 R14: ffffffff816fae20 R15: ffffc900032eed28 arch_stack_walk+0x100/0x140 arch/x86/kernel/stacktrace.c:27 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc_node_track_caller+0xae/0x230 mm/slab_common.c:956 __do_krealloc mm/slab_common.c:1336 [inline] krealloc+0x6a/0x100 mm/slab_common.c:1369 push_jmp_history kernel/bpf/verifier.c:2479 [inline] is_state_visited kernel/bpf/verifier.c:12311 [inline] do_check kernel/bpf/verifier.c:12451 [inline] do_check_common+0x41bd/0xc6a0 kernel/bpf/verifier.c:14933 do_check_main kernel/bpf/verifier.c:14996 [inline] bpf_check+0x3ee1/0x10ca0 kernel/bpf/verifier.c:15573 bpf_prog_load+0x1072/0x15a0 kernel/bpf/syscall.c:2641 __sys_bpf+0x520/0x6d0 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+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe87b58e929 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:00007fe87b3ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fe87b7b5fa0 RCX: 00007fe87b58e929 RDX: 0000000000000048 RSI: 0000200000000200 RDI: 0000000000000005 RBP: 00007fe87b610b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fe87b7b5fa0 R15: 00007ffc9752c358 ---------------- Code disassembly (best guess): 0: 48 8b 0c 25 28 00 00 mov 0x28,%rcx 7: 00 8: 48 3b 4c 24 78 cmp 0x78(%rsp),%rcx d: 75 09 jne 0x18 f: 48 8d 65 f0 lea -0x10(%rbp),%rsp 13: 5b pop %rbx 14: 41 5e pop %r14 16: 5d pop %rbp 17: c3 ret 18: e8 fd e2 9f 08 call 0x89fe31a 1d: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1) 24: 00 00 00 27: 0f 1f 00 nopl (%rax) * 2a: 55 push %rbp <-- trapping instruction 2b: 41 57 push %r15 2d: 41 56 push %r14 2f: 41 55 push %r13 31: 41 54 push %r12 33: 53 push %rbx 34: 48 83 ec 18 sub $0x18,%rsp 38: 48 rex.W 39: ba 00 00 00 00 mov $0x0,%edx 3e: 00 fc add %bh,%ah