====================================================== WARNING: possible circular locking dependency detected 6.1.127-syzkaller #0 Not tainted ------------------------------------------------------ syz.9.5146/19187 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:1770 inet_init+0x2ae/0x3c0 net/ipv4/af_inet.c:2033 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:545 bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline] bpf_trace_run3+0x231/0x440 kernel/trace/bpf_trace.c:2324 trace_timer_start include/trace/events/timer.h:53 [inline] enqueue_timer+0x440/0x600 kernel/time/timer.c:609 __mod_timer+0x92b/0xee0 dsp_cmx_send+0x21bb/0x2240 drivers/isdn/mISDN/dsp_cmx.c:1850 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 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 zap_pmd_range mm/memory.c:1574 [inline] zap_pud_range mm/memory.c:1603 [inline] zap_p4d_range mm/memory.c:1624 [inline] unmap_page_range+0x1017/0x2740 mm/memory.c:1645 unmap_vmas+0x48b/0x640 mm/memory.c:1730 exit_mmap+0x249/0x980 mm/mmap.c:3238 __mmput+0x115/0x3c0 kernel/fork.c:1200 exit_mm+0x226/0x300 kernel/exit.c:565 do_exit+0x9f1/0x26a0 kernel/exit.c:858 do_group_exit+0x202/0x2b0 kernel/exit.c:1021 get_signal+0x16f7/0x17d0 kernel/signal.c:2871 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 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 *** 6 locks held by syz.9.5146/19187: #0: ffff88801e357958 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline] #0: ffff88801e357958 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x1b6/0x980 mm/mmap.c:3223 #1: ffff888027b16618 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #1: ffff888027b16618 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pte_range mm/memory.c:1417 [inline] #1: ffff888027b16618 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pmd_range mm/memory.c:1574 [inline] #1: ffff888027b16618 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pud_range mm/memory.c:1603 [inline] #1: ffff888027b16618 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_p4d_range mm/memory.c:1624 [inline] #1: ffff888027b16618 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: unmap_page_range+0xacc/0x2740 mm/memory.c:1645 #2: ffffc900001e0bc0 ((&dsp_spl_tl)){+.-.}-{0:0}, at: call_timer_fn+0xc2/0x6b0 kernel/time/timer.c:1501 #3: ffffffff8e2a5bb8 (dsp_lock){..-.}-{2:2}, at: dsp_cmx_send+0x22/0x2240 drivers/isdn/mISDN/dsp_cmx.c:1643 #4: ffff8880b8f28358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:999 #5: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #5: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #5: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline] #5: ffffffff8d32b0c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x146/0x440 kernel/trace/bpf_trace.c:2324 stack backtrace: CPU: 1 PID: 19187 Comm: syz.9.5146 Not tainted 6.1.127-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 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:545 bpf_prog_2c29ac5cdc6b1842+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline] bpf_trace_run3+0x231/0x440 kernel/trace/bpf_trace.c:2324 trace_timer_start include/trace/events/timer.h:53 [inline] enqueue_timer+0x440/0x600 kernel/time/timer.c:609 __mod_timer+0x92b/0xee0 dsp_cmx_send+0x21bb/0x2240 drivers/isdn/mISDN/dsp_cmx.c:1850 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 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:zap_pte_range mm/memory.c:1444 [inline] RIP: 0010:zap_pmd_range mm/memory.c:1574 [inline] RIP: 0010:zap_pud_range mm/memory.c:1603 [inline] RIP: 0010:zap_p4d_range mm/memory.c:1624 [inline] RIP: 0010:unmap_page_range+0x1017/0x2740 mm/memory.c:1645 Code: 80 3c 08 00 74 08 48 89 df e8 65 e6 15 00 48 8b 1b 48 89 de 48 83 e6 01 31 ff e8 44 57 be ff 48 83 e3 01 75 26 48 8b 5c 24 68 <89> de 83 e6 40 31 ff e8 ad 56 be ff 89 d8 83 e0 40 0f 85 80 00 00 RSP: 0018:ffffc900033af320 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 8000000058fbe027 RCX: ffff888019311dc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900033af510 R08: ffffffff81cc493c R09: fffffbfff1d364e6 R10: 0000000000000000 R11: dffffc0000000001 R12: ffffea000163ef80 R13: ffff888027d32c48 R14: 1ffffd40002c7df1 R15: ffffea000163ef88 unmap_vmas+0x48b/0x640 mm/memory.c:1730 exit_mmap+0x249/0x980 mm/mmap.c:3238 __mmput+0x115/0x3c0 kernel/fork.c:1200 exit_mm+0x226/0x300 kernel/exit.c:565 do_exit+0x9f1/0x26a0 kernel/exit.c:858 do_group_exit+0x202/0x2b0 kernel/exit.c:1021 get_signal+0x16f7/0x17d0 kernel/signal.c:2871 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f7e0ff8cd29 Code: Unable to access opcode bytes at 0x7f7e0ff8ccff. RSP: 002b:00007f7e10e570e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f7e101a5fa8 RCX: 00007f7e0ff8cd29 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f7e101a5fa8 RBP: 00007f7e101a5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7e101a5fac R13: 0000000000000000 R14: 00007ffefd3e94b0 R15: 00007ffefd3e9598 ---------------- Code disassembly (best guess): 0: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) 4: 74 08 je 0xe 6: 48 89 df mov %rbx,%rdi 9: e8 65 e6 15 00 call 0x15e673 e: 48 8b 1b mov (%rbx),%rbx 11: 48 89 de mov %rbx,%rsi 14: 48 83 e6 01 and $0x1,%rsi 18: 31 ff xor %edi,%edi 1a: e8 44 57 be ff call 0xffbe5763 1f: 48 83 e3 01 and $0x1,%rbx 23: 75 26 jne 0x4b 25: 48 8b 5c 24 68 mov 0x68(%rsp),%rbx * 2a: 89 de mov %ebx,%esi <-- trapping instruction 2c: 83 e6 40 and $0x40,%esi 2f: 31 ff xor %edi,%edi 31: e8 ad 56 be ff call 0xffbe56e3 36: 89 d8 mov %ebx,%eax 38: 83 e0 40 and $0x40,%eax 3b: 0f .byte 0xf 3c: 85 .byte 0x85 3d: 80 00 00 addb $0x0,(%rax)