====================================================== WARNING: possible circular locking dependency detected 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0 Not tainted ------------------------------------------------------ syz-executor.4/5848 is trying to acquire lock: ffff8880b9229558 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3298 [inline] ffff8880b9229558 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3697 [inline] ffff8880b9229558 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0xda/0xbe0 kernel/rcu/tree.c:3782 but task is already holding lock: ffff8880b922a858 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x5d/0x220 kernel/time/timer.c:1051 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&base->lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 lock_timer_base+0x5d/0x220 kernel/time/timer.c:1051 __mod_timer+0x426/0xdc0 kernel/time/timer.c:1132 add_timer_global+0x8a/0xc0 kernel/time/timer.c:1330 __queue_delayed_work+0x1ba/0x2e0 kernel/workqueue.c:2543 queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2572 kvfree_call_rcu+0x749/0xbe0 kernel/rcu/tree.c:3810 rtnl_register_internal+0x343/0x670 net/core/rtnetlink.c:265 rtnl_register+0x34/0x80 net/core/rtnetlink.c:315 ip_rt_init+0x34a/0x450 net/ipv4/route.c:3696 ip_init+0xe/0x20 net/ipv4/ip_output.c:1663 inet_init+0x3f0/0x6f0 net/ipv4/af_inet.c:1983 do_one_initcall+0x12b/0x700 init/main.c:1267 do_initcall_level init/main.c:1329 [inline] do_initcalls init/main.c:1345 [inline] do_basic_setup init/main.c:1364 [inline] kernel_init_freeable+0x69d/0xca0 init/main.c:1578 kernel_init+0x1c/0x2b0 init/main.c:1467 ret_from_fork+0x48/0x80 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 kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __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:3298 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3697 [inline] kvfree_call_rcu+0xda/0xbe0 kernel/rcu/tree.c:3782 trie_delete_elem+0x5c5/0x820 kernel/bpf/lpm_trie.c:540 bpf_prog_2c29ac5cdc6b1842+0x42/0x4a 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:2403 [inline] bpf_trace_run2+0x234/0x590 kernel/trace/bpf_trace.c:2444 __bpf_trace_timer_start+0xc7/0x100 include/trace/events/timer.h:52 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x2b4/0x550 kernel/time/timer.c:663 internal_add_timer kernel/time/timer.c:688 [inline] __mod_timer+0x8d7/0xdc0 kernel/time/timer.c:1183 call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792 expire_timers kernel/time/timer.c:1843 [inline] __run_timers+0x74b/0xaf0 kernel/time/timer.c:2417 __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447 handle_softirqs+0x219/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 stack_access_ok+0xfc/0x270 arch/x86/kernel/unwind_orc.c:398 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0xd9b/0x23a0 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 save_stack+0x162/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x8d/0x400 mm/page_owner.c:297 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1088 [inline] free_unref_folios+0x991/0x1310 mm/page_alloc.c:2632 folios_put_refs+0x487/0x6d0 mm/swap.c:1024 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x5a1/0x1160 mm/shmem.c:1005 shmem_truncate_range mm/shmem.c:1114 [inline] shmem_evict_inode+0x3a3/0xbb0 mm/shmem.c:1242 evict+0x2f0/0x6c0 fs/inode.c:667 iput_final fs/inode.c:1741 [inline] iput.part.0+0x5a8/0x7f0 fs/inode.c:1767 iput+0x5c/0x80 fs/inode.c:1757 dentry_unlink_inode+0x295/0x480 fs/dcache.c:400 __dentry_kill+0x1d0/0x600 fs/dcache.c:603 dput.part.0+0x4b1/0x9b0 fs/dcache.c:845 dput+0x1f/0x30 fs/dcache.c:835 __fput+0x54e/0xbb0 fs/file_table.c:430 task_work_run+0x151/0x250 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa9b/0x2ba0 kernel/exit.c:874 do_group_exit+0xd3/0x2a0 kernel/exit.c:1023 get_signal+0x2616/0x2710 kernel/signal.c:2909 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x14a/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 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 *** 4 locks held by syz-executor.4/5848: #0: ffffffff8dbb5be0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #0: ffffffff8dbb5be0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #0: ffffffff8dbb5be0 (rcu_read_lock){....}-{1:2}, at: page_ext_get+0x34/0x310 mm/page_ext.c:521 #1: ffffc90000007cb0 ((&app->join_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11a/0x610 kernel/time/timer.c:1789 #2: ffff8880b922a858 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x5d/0x220 kernel/time/timer.c:1051 #3: ffffffff8dbb5be0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #3: ffffffff8dbb5be0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #3: ffffffff8dbb5be0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2402 [inline] #3: ffffffff8dbb5be0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2444 stack backtrace: CPU: 0 PID: 5848 Comm: syz-executor.4 Not tainted 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/0x400 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 kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __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:3298 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3697 [inline] kvfree_call_rcu+0xda/0xbe0 kernel/rcu/tree.c:3782 trie_delete_elem+0x5c5/0x820 kernel/bpf/lpm_trie.c:540 bpf_prog_2c29ac5cdc6b1842+0x42/0x4a 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:2403 [inline] bpf_trace_run2+0x234/0x590 kernel/trace/bpf_trace.c:2444 __bpf_trace_timer_start+0xc7/0x100 include/trace/events/timer.h:52 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x2b4/0x550 kernel/time/timer.c:663 internal_add_timer kernel/time/timer.c:688 [inline] __mod_timer+0x8d7/0xdc0 kernel/time/timer.c:1183 call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792 expire_timers kernel/time/timer.c:1843 [inline] __run_timers+0x74b/0xaf0 kernel/time/timer.c:2417 __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447 handle_softirqs+0x219/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:stack_access_ok+0xfc/0x270 arch/x86/kernel/unwind_orc.c:398 Code: 8b 73 28 48 89 da 48 89 ef e8 20 bd f3 ff 31 ff 41 89 c6 89 c6 e8 34 54 52 00 45 85 f6 74 1e 45 31 f6 e8 27 59 52 00 44 89 f0 <48> 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f e9 7c 6b d3 09 e8 0c 59 RSP: 0018:ffffc90015daefb8 EFLAGS: 00000293 RAX: 0000000000000001 RBX: ffffc90015daf080 RCX: ffffffff813cd516 RDX: ffff88801e915a00 RSI: ffffffff813cd579 RDI: 0000000000000005 RBP: ffffc90015daf2b8 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90015daf088 R13: ffffc90015daf090 R14: 0000000000000001 R15: ffffc90015db0000 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0xd9b/0x23a0 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 save_stack+0x162/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x8d/0x400 mm/page_owner.c:297 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1088 [inline] free_unref_folios+0x991/0x1310 mm/page_alloc.c:2632 folios_put_refs+0x487/0x6d0 mm/swap.c:1024 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x5a1/0x1160 mm/shmem.c:1005 shmem_truncate_range mm/shmem.c:1114 [inline] shmem_evict_inode+0x3a3/0xbb0 mm/shmem.c:1242 evict+0x2f0/0x6c0 fs/inode.c:667 iput_final fs/inode.c:1741 [inline] iput.part.0+0x5a8/0x7f0 fs/inode.c:1767 iput+0x5c/0x80 fs/inode.c:1757 dentry_unlink_inode+0x295/0x480 fs/dcache.c:400 __dentry_kill+0x1d0/0x600 fs/dcache.c:603 dput.part.0+0x4b1/0x9b0 fs/dcache.c:845 dput+0x1f/0x30 fs/dcache.c:835 __fput+0x54e/0xbb0 fs/file_table.c:430 task_work_run+0x151/0x250 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa9b/0x2ba0 kernel/exit.c:874 do_group_exit+0xd3/0x2a0 kernel/exit.c:1023 get_signal+0x2616/0x2710 kernel/signal.c:2909 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x14a/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa0b467cea9 Code: Unable to access opcode bytes at 0x7fa0b467ce7f. RSP: 002b:00007fa0b53ff0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007fa0b47b4050 RCX: 00007fa0b467cea9 RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00007fa0b46ebff4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fa0b47b4050 R15: 00007fff10fbfa08 ---------------- Code disassembly (best guess): 0: 8b 73 28 mov 0x28(%rbx),%esi 3: 48 89 da mov %rbx,%rdx 6: 48 89 ef mov %rbp,%rdi 9: e8 20 bd f3 ff call 0xfff3bd2e e: 31 ff xor %edi,%edi 10: 41 89 c6 mov %eax,%r14d 13: 89 c6 mov %eax,%esi 15: e8 34 54 52 00 call 0x52544e 1a: 45 85 f6 test %r14d,%r14d 1d: 74 1e je 0x3d 1f: 45 31 f6 xor %r14d,%r14d 22: e8 27 59 52 00 call 0x52594e 27: 44 89 f0 mov %r14d,%eax * 2a: 48 83 c4 10 add $0x10,%rsp <-- trapping instruction 2e: 5b pop %rbx 2f: 5d pop %rbp 30: 41 5c pop %r12 32: 41 5d pop %r13 34: 41 5e pop %r14 36: 41 5f pop %r15 38: e9 7c 6b d3 09 jmp 0x9d36bb9 3d: e8 .byte 0xe8 3e: 0c 59 or $0x59,%al