============================================ WARNING: possible recursive locking detected 6.9.0-rc7-syzkaller #0 Not tainted -------------------------------------------- udevd/8818 is trying to acquire lock: ffff8880456951d8 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x353/0x420 kernel/bpf/queue_stack_maps.c:210 but task is already holding lock: ffff8880456931d8 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x353/0x420 kernel/bpf/queue_stack_maps.c:210 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&qs->lock); lock(&qs->lock); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by udevd/8818: #0: ffff888047261068 (&ep->mtx){+.+.}-{3:3}, at: ep_send_events fs/eventpoll.c:1835 [inline] #0: ffff888047261068 (&ep->mtx){+.+.}-{3:3}, at: ep_poll fs/eventpoll.c:2005 [inline] #0: ffff888047261068 (&ep->mtx){+.+.}-{3:3}, at: do_epoll_wait+0xaba/0x1ae0 fs/eventpoll.c:2464 #1: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #1: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #1: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline] #1: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xe4/0x420 kernel/trace/bpf_trace.c:2420 #2: ffff8880456931d8 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x353/0x420 kernel/bpf/queue_stack_maps.c:210 #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline] #3: ffffffff8d7b0e20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xe4/0x420 kernel/trace/bpf_trace.c:2420 stack backtrace: CPU: 3 PID: 8818 Comm: udevd Not tainted 6.9.0-rc7-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x20e6/0x3b30 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_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 queue_stack_map_push_elem+0x353/0x420 kernel/bpf/queue_stack_maps.c:210 ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997 __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end.constprop.0+0xea/0x170 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x266/0xc80 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [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+0x210/0x2c0 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162 queue_stack_map_push_elem+0x353/0x420 kernel/bpf/queue_stack_maps.c:210 ___bpf_prog_run+0x3e51/0xabd0 kernel/bpf/core.c:1997 __bpf_prog_run32+0xc1/0x100 kernel/bpf/core.c:2236 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] __bpf_prog_run include/linux/filter.h:657 [inline] bpf_prog_run include/linux/filter.h:664 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run2+0x151/0x420 kernel/trace/bpf_trace.c:2420 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end+0xce/0x140 include/trace/events/lock.h:122 __mutex_lock_common kernel/locking/mutex.c:617 [inline] __mutex_lock+0x19c/0x9c0 kernel/locking/mutex.c:752 ep_send_events fs/eventpoll.c:1835 [inline] ep_poll fs/eventpoll.c:2005 [inline] do_epoll_wait+0xaba/0x1ae0 fs/eventpoll.c:2464 __do_sys_epoll_wait fs/eventpoll.c:2476 [inline] __se_sys_epoll_wait fs/eventpoll.c:2471 [inline] __x64_sys_epoll_wait+0x194/0x290 fs/eventpoll.c:2471 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9a4b923457 Code: 73 01 c3 48 8b 0d d1 d9 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 e8 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 76 48 8b 15 a2 d9 0c 00 f7 d8 64 89 02 48 83 RSP: 002b:00007fff3c4bb158 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9a4b923457 RDX: 0000000000000004 RSI: 00007fff3c4bb198 RDI: 0000000000000004 RBP: 000055ae8aee2ed0 R08: 0000000000000007 R09: 4fe05f3fc7111751 R10: 00000000ffffffff R11: 0000000000000246 R12: 000055ae8af57ef0 R13: 00007fff3c4bb198 R14: 0000000000000008 R15: 000055ae8aeb72c0 blk_print_req_error: 15 callbacks suppressed I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0