====================================================== WARNING: possible circular locking dependency detected 6.1.111-syzkaller #0 Not tainted ------------------------------------------------------ syz.1.92/4048 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_41385012b43a9f2e+0x40/0x44 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 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 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 is_huge_zero_page include/linux/huge_mm.h:273 [inline] release_pages+0x24a/0x2b40 mm/swap.c:998 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline] tlb_flush_mmu_free mm/mmu_gather.c:254 [inline] tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261 tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361 exit_mmap+0x3c3/0x9f0 mm/mmap.c:3239 __mmput+0x115/0x3c0 kernel/fork.c:1199 exit_mm+0x226/0x300 kernel/exit.c:565 do_exit+0x9f6/0x26a0 kernel/exit.c:858 __do_sys_exit kernel/exit.c:988 [inline] __se_sys_exit kernel/exit.c:986 [inline] __x64_sys_exit+0x3c/0x40 kernel/exit.c:986 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.1.92/4048: #0: ffff88807bc98158 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline] #0: ffff88807bc98158 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x29a/0x9f0 mm/mmap.c:3235 #1: ffffc900001e0bc0 ((&dsp_spl_tl)){+.-.}-{0:0}, at: call_timer_fn+0xc2/0x6b0 kernel/time/timer.c:1501 #2: ffffffff8e294138 (dsp_lock){..-.}-{2:2}, at: dsp_cmx_send+0x22/0x2240 drivers/isdn/mISDN/dsp_cmx.c:1643 #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: 4048 Comm: syz.1.92 Not tainted 6.1.111-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 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_41385012b43a9f2e+0x40/0x44 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 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 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:is_huge_zero_page include/linux/huge_mm.h:273 [inline] RIP: 0010:release_pages+0x24a/0x2b40 mm/swap.c:998 Code: bc d2 f3 08 c7 44 24 44 20 00 00 00 eb 05 e8 1d 43 cd ff 45 31 ed eb 05 e8 13 43 cd ff 48 8b 84 24 88 00 00 00 42 80 3c 38 00 <74> 0c 48 c7 c7 a0 f0 99 8e e8 38 c5 24 00 48 8b 05 51 84 dc 0c 4c RSP: 0018:ffffc900060378e0 EFLAGS: 00000246 RAX: 1ffffffff1d33e14 RBX: 0000000000000000 RCX: ffff8880259c5940 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90006037a60 R08: ffffffff81bd6bab R09: fffff940001408d7 R10: 0000000000000000 R11: dffffc0000000001 R12: 000000000000016c R13: 0000000000000000 R14: ffffea0000a046c0 R15: dffffc0000000000 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline] tlb_flush_mmu_free mm/mmu_gather.c:254 [inline] tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261 tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361 exit_mmap+0x3c3/0x9f0 mm/mmap.c:3239 __mmput+0x115/0x3c0 kernel/fork.c:1199 exit_mm+0x226/0x300 kernel/exit.c:565 do_exit+0x9f6/0x26a0 kernel/exit.c:858 __do_sys_exit kernel/exit.c:988 [inline] __se_sys_exit kernel/exit.c:986 [inline] __x64_sys_exit+0x3c/0x40 kernel/exit.c:986 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: 0033:0x7ff7f237def9 Code: Unable to access opcode bytes at 0x7ff7f237decf. RSP: 002b:00007ff7f31fafe8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c RAX: ffffffffffffffda RBX: 00007ff7f2536208 RCX: 00007ff7f237def9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ff7f23f0b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007ff7f2536208 R15: 00007ffd43b30f68 ---------------- Code disassembly (best guess): 0: bc d2 f3 08 c7 mov $0xc708f3d2,%esp 5: 44 24 44 rex.R and $0x44,%al 8: 20 00 and %al,(%rax) a: 00 00 add %al,(%rax) c: eb 05 jmp 0x13 e: e8 1d 43 cd ff call 0xffcd4330 13: 45 31 ed xor %r13d,%r13d 16: eb 05 jmp 0x1d 18: e8 13 43 cd ff call 0xffcd4330 1d: 48 8b 84 24 88 00 00 mov 0x88(%rsp),%rax 24: 00 25: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) * 2a: 74 0c je 0x38 <-- trapping instruction 2c: 48 c7 c7 a0 f0 99 8e mov $0xffffffff8e99f0a0,%rdi 33: e8 38 c5 24 00 call 0x24c570 38: 48 8b 05 51 84 dc 0c mov 0xcdc8451(%rip),%rax # 0xcdc8490 3f: 4c rex.WR