====================================================== WARNING: possible circular locking dependency detected 5.15.173-syzkaller #0 Not tainted ------------------------------------------------------ udevd/7881 is trying to acquire lock: ffff88801f6be9b8 (&trie->lock){..-.}-{2:2}, at: trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:450 but task is already holding lock: ffff8880b9128098 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:946 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&base->lock){-.-.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __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:946 __mod_timer+0x1d6/0xeb0 kernel/time/timer.c:1019 queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1715 queue_delayed_work include/linux/workqueue.h:527 [inline] schedule_delayed_work include/linux/workqueue.h:631 [inline] kvfree_call_rcu+0x50e/0x8a0 kernel/rcu/tree.c:3625 rtnl_register_internal+0x443/0x530 net/core/rtnetlink.c:223 rtnl_register+0x32/0x70 net/core/rtnetlink.c:273 ip_rt_init+0x2e6/0x390 net/ipv4/route.c:3750 ip_init+0xa/0x20 net/ipv4/ip_output.c:1749 inet_init+0x27c/0x390 net/ipv4/af_inet.c:2009 do_one_initcall+0x22b/0x7a0 init/main.c:1302 do_initcall_level+0x157/0x210 init/main.c:1375 do_initcalls+0x49/0x90 init/main.c:1391 kernel_init_freeable+0x425/0x5c0 init/main.c:1615 kernel_init+0x19/0x290 init/main.c:1506 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #1 (krc.lock){..-.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 krc_this_cpu_lock kernel/rcu/tree.c:3199 [inline] add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline] kvfree_call_rcu+0x1b5/0x8a0 kernel/rcu/tree.c:3597 trie_delete_elem+0x520/0x690 0xffffffffa0090991 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916 __bpf_trace_kmem_cache_free+0x99/0xc0 include/trace/events/kmem.h:138 trace_kmem_cache_free include/trace/events/kmem.h:138 [inline] kmem_cache_free+0x1ce/0x1f0 mm/slub.c:3516 do_sys_openat2+0x202/0x4f0 fs/open.c:1262 do_sys_open fs/open.c:1269 [inline] __do_sys_creat fs/open.c:1345 [inline] __se_sys_creat fs/open.c:1339 [inline] __x64_sys_creat+0x11f/0x160 fs/open.c:1339 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&trie->lock){..-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:450 bpf_prog_2c29ac5cdc6b1842+0x3a/0xbe0 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ae/0x540 kernel/time/timer.c:586 internal_add_timer kernel/time/timer.c:611 [inline] __mod_timer+0xa60/0xeb0 kernel/time/timer.c:1062 queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1715 queue_delayed_work include/linux/workqueue.h:527 [inline] fsnotify_put_mark+0x5f3/0x700 fs/notify/mark.c:369 __do_sys_inotify_rm_watch fs/notify/inotify/inotify_user.c:812 [inline] __se_sys_inotify_rm_watch+0x16c/0x230 fs/notify/inotify/inotify_user.c:786 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: &trie->lock --> krc.lock --> &base->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&base->lock); lock(krc.lock); lock(&base->lock); lock(&trie->lock); *** DEADLOCK *** 2 locks held by udevd/7881: #0: ffff8880b9128098 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:946 #1: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 stack backtrace: CPU: 1 PID: 7881 Comm: udevd Not tainted 5.15.173-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:450 bpf_prog_2c29ac5cdc6b1842+0x3a/0xbe0 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ae/0x540 kernel/time/timer.c:586 internal_add_timer kernel/time/timer.c:611 [inline] __mod_timer+0xa60/0xeb0 kernel/time/timer.c:1062 queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1715 queue_delayed_work include/linux/workqueue.h:527 [inline] fsnotify_put_mark+0x5f3/0x700 fs/notify/mark.c:369 __do_sys_inotify_rm_watch fs/notify/inotify/inotify_user.c:812 [inline] __se_sys_inotify_rm_watch+0x16c/0x230 fs/notify/inotify/inotify_user.c:786 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f6359177f77 Code: 73 01 c3 48 8b 0d b1 ce 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 ff 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 ce 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc4a38a198 EFLAGS: 00000246 ORIG_RAX: 00000000000000ff RAX: ffffffffffffffda RBX: 00005601ab5e3120 RCX: 00007f6359177f77 RDX: 0000000000000007 RSI: 0000000000000707 RDI: 0000000000000007 RBP: 00005601b8d44d20 R08: 0000000000000006 R09: d563c21f7846ae44 R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000000707 R13: 00007ffc4a38a1a8 R14: 0000000003938700 R15: 00005601ab5e3160