============================================ WARNING: possible recursive locking detected 6.0.0-rc1-syzkaller-00245-g268603d79cc4 #0 Not tainted -------------------------------------------- syz-executor.5/13682 is trying to acquire lock: ffffffff8c011138 (trace_printk_lock){..-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] ffffffff8c011138 (trace_printk_lock){..-.}-{2:2}, at: bpf_trace_printk+0xcf/0x170 kernel/trace/bpf_trace.c:374 but task is already holding lock: ffffffff8c011138 (trace_printk_lock){..-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] ffffffff8c011138 (trace_printk_lock){..-.}-{2:2}, at: bpf_trace_printk+0xcf/0x170 kernel/trace/bpf_trace.c:374 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(trace_printk_lock); lock(trace_printk_lock); *** DEADLOCK *** May be due to missing lock nesting notation 5 locks held by syz-executor.5/13682: #0: ffffffff8d79ac50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2f5/0x760 net/core/net_namespace.c:468 #1: ffffffff8bf93e40 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x44/0x720 kernel/rcu/tree.c:3788 #2: ffffffff8bf892c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x0/0x340 kernel/trace/./bpf_trace.h:11 #3: ffffffff8c011138 (trace_printk_lock){..-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] #3: ffffffff8c011138 (trace_printk_lock){..-.}-{2:2}, at: bpf_trace_printk+0xcf/0x170 kernel/trace/bpf_trace.c:374 #4: ffffffff8bf892c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x0/0x340 kernel/trace/./bpf_trace.h:11 stack backtrace: CPU: 0 PID: 13682 Comm: syz-executor.5 Not tainted 6.0.0-rc1-syzkaller-00245-g268603d79cc4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2988 [inline] check_deadlock kernel/locking/lockdep.c:3031 [inline] validate_chain kernel/locking/lockdep.c:3816 [inline] __lock_acquire.cold+0x116/0x3a7 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] bpf_trace_printk+0xcf/0x170 kernel/trace/bpf_trace.c:374 bpf_prog_0605f9f479290f07+0x2f/0x33 bpf_dispatcher_nop_func include/linux/bpf.h:903 [inline] __bpf_prog_run include/linux/filter.h:594 [inline] bpf_prog_run include/linux/filter.h:601 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2046 [inline] bpf_trace_run2+0x110/0x340 kernel/trace/bpf_trace.c:2083 __bpf_trace_contention_begin+0xb5/0xf0 include/trace/events/lock.h:95 trace_contention_begin.constprop.0+0xda/0x1b0 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0x103/0xb50 kernel/locking/qspinlock.c:405 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x200/0x2a0 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0x41/0x50 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] bpf_trace_printk+0xcf/0x170 kernel/trace/bpf_trace.c:374 bpf_prog_0605f9f479290f07+0x2f/0x33 bpf_dispatcher_nop_func include/linux/bpf.h:903 [inline] __bpf_prog_run include/linux/filter.h:594 [inline] bpf_prog_run include/linux/filter.h:601 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2046 [inline] bpf_trace_run2+0x110/0x340 kernel/trace/bpf_trace.c:2083 __bpf_trace_contention_begin+0xb5/0xf0 include/trace/events/lock.h:95 trace_contention_begin+0xc0/0x150 include/trace/events/lock.h:95 __mutex_lock_common kernel/locking/mutex.c:605 [inline] __mutex_lock+0x13c/0x1350 kernel/locking/mutex.c:747 rcu_barrier+0x44/0x720 kernel/rcu/tree.c:3788 netdev_run_todo+0x2a5/0x10f0 net/core/dev.c:10348 ip_tunnel_delete_nets+0x3a4/0x5b0 net/ipv4/ip_tunnel.c:1126 ops_exit_list+0x125/0x170 net/core/net_namespace.c:168 setup_net+0x7fb/0xc50 net/core/net_namespace.c:349 copy_net_ns+0x318/0x760 net/core/net_namespace.c:472 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:227 ksys_unshare+0x445/0x920 kernel/fork.c:3183 __do_sys_unshare kernel/fork.c:3254 [inline] __se_sys_unshare kernel/fork.c:3252 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3252 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f724b889279 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f724ca4a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f724b99bf80 RCX: 00007f724b889279 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006c060000 RBP: 00007f724b8e3189 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe6a26f37f R14: 00007f724ca4a300 R15: 0000000000022000