============================================ WARNING: possible recursive locking detected 5.19.0-rc7-syzkaller-00199-g515f71412bb7 #0 Not tainted -------------------------------------------- udevd/9711 is trying to acquire lock: ffffffff8cb7b258 (trace_printk_lock){-.-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] ffffffff8cb7b258 (trace_printk_lock){-.-.}-{2:2}, at: bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 but task is already holding lock: ffffffff8cb7b258 (trace_printk_lock){-.-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] ffffffff8cb7b258 (trace_printk_lock){-.-.}-{2:2}, at: bpf_trace_printk+0x151/0x200 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 4 locks held by udevd/9711: #0: ffff88801d0e4c68 (&ep->mtx){+.+.}-{3:3}, at: ep_send_events fs/eventpoll.c:1655 [inline] #0: ffff88801d0e4c68 (&ep->mtx){+.+.}-{3:3}, at: ep_poll+0x5e2/0x1e60 fs/eventpoll.c:1806 #1: ffffffff8cb1eea0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:268 #2: ffffffff8cb7b258 (trace_printk_lock){-.-.}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] #2: ffffffff8cb7b258 (trace_printk_lock){-.-.}-{2:2}, at: bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 #3: ffffffff8cb1eea0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:268 stack backtrace: CPU: 1 PID: 9711 Comm: udevd Not tainted 5.19.0-rc7-syzkaller-00199-g515f71412bb7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2988 [inline] check_deadlock kernel/locking/lockdep.c:3031 [inline] validate_chain+0x485d/0x65c0 kernel/locking/lockdep.c:3816 __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5053 lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5665 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 bpf_prog_0605f9f479290f07+0x2f/0x33 bpf_dispatcher_nop_func include/linux/bpf.h:869 [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:2046 [inline] bpf_trace_run2+0x18a/0x320 kernel/trace/bpf_trace.c:2083 trace_contention_end+0x165/0x190 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x93f/0xc60 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x264/0x360 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xdd/0x120 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 bpf_prog_0605f9f479290f07+0x2f/0x33 bpf_dispatcher_nop_func include/linux/bpf.h:869 [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:2046 [inline] bpf_trace_run2+0x18a/0x320 kernel/trace/bpf_trace.c:2083 trace_contention_end+0x116/0x140 include/trace/events/lock.h:122 __mutex_lock_common+0x453/0x26c0 kernel/locking/mutex.c:612 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799 ep_send_events fs/eventpoll.c:1655 [inline] ep_poll+0x5e2/0x1e60 fs/eventpoll.c:1806 do_epoll_wait+0x1a2/0x210 fs/eventpoll.c:2234 __do_sys_epoll_wait fs/eventpoll.c:2246 [inline] __se_sys_epoll_wait fs/eventpoll.c:2241 [inline] __x64_sys_epoll_wait+0x2b2/0x300 fs/eventpoll.c:2241 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f73fd133e46 Code: 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 11 b8 e8 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 90 48 83 ec 28 89 54 24 18 48 89 74 24 RSP: 002b:00007ffdf412c2e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f73fd133e46 RDX: 0000000000000004 RSI: 00007ffdf412c328 RDI: 0000000000000004 RBP: 0000563375691cb0 R08: 0000000000000007 R09: 0000563375686720 R10: 00000000ffffffff R11: 0000000000000246 R12: 0000563375728020 R13: 00007ffdf412c328 R14: 0000000000000008 R15: 000056337566c910