============================================ WARNING: possible recursive locking detected 6.9.0-rc5-syzkaller-01502-gfcd1ed89a043 #0 Not tainted -------------------------------------------- udevd/4538 is trying to acquire lock: ffff8880227a61d8 (&qs->lock){..-.}-{2:2}, at: __stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140 but task is already holding lock: ffff88802c7de1d8 (&qs->lock){..-.}-{2:2}, at: queue_stack_map_push_elem+0x1b2/0x660 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 5 locks held by udevd/4538: #0: ffffffff8e334ee0 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #0: ffffffff8e334ee0 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2190 [inline] #0: ffffffff8e334ee0 (rcu_callback){....}-{0:0}, at: rcu_core+0xa86/0x1830 kernel/rcu/tree.c:2471 #1: ffffffff8e1d5380 (put_task_map-wait-type-override){+...}-{3:3}, at: put_task_struct include/linux/sched/task.h:137 [inline] #1: ffffffff8e1d5380 (put_task_map-wait-type-override){+...}-{3:3}, at: delayed_put_task_struct+0xfa/0x2f0 kernel/exit.c:229 #2: ffffffff8e334e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #2: ffffffff8e334e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #2: ffffffff8e334e20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2402 [inline] #2: ffffffff8e334e20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x24c/0x5a0 kernel/trace/bpf_trace.c:2445 #3: ffff88802c7de1d8 (&qs->lock){..-.}-{2:2}, at: queue_stack_map_push_elem+0x1b2/0x660 kernel/bpf/queue_stack_maps.c:210 #4: ffffffff8e334e20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #4: ffffffff8e334e20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #4: ffffffff8e334e20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2402 [inline] #4: ffffffff8e334e20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1fc/0x540 kernel/trace/bpf_trace.c:2444 stack backtrace: CPU: 1 PID: 4538 Comm: udevd Not tainted 6.9.0-rc5-syzkaller-01502-gfcd1ed89a043 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 __stack_map_get+0x14b/0x4b0 kernel/bpf/queue_stack_maps.c:140 bpf_prog_00798911c748094f+0x42/0x46 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+0x2ec/0x540 kernel/trace/bpf_trace.c:2444 trace_contention_end+0x114/0x140 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x939/0xc60 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [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+0x272/0x370 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xe1/0x120 kernel/locking/spinlock.c:162 queue_stack_map_push_elem+0x1b2/0x660 kernel/bpf/queue_stack_maps.c:210 bpf_prog_216c997a1f42e404+0x3f/0x43 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_run3+0x33a/0x5a0 kernel/trace/bpf_trace.c:2445 trace_kmem_cache_free include/trace/events/kmem.h:114 [inline] kmem_cache_free+0x25a/0x2c0 mm/slub.c:4343 put_task_struct include/linux/sched/task.h:138 [inline] delayed_put_task_struct+0x125/0x2f0 kernel/exit.c:229 rcu_do_batch kernel/rcu/tree.c:2196 [inline] rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2471 __do_softirq+0x2c6/0x980 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:80 [inline] RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:102 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x4fb/0x2a00 arch/x86/kernel/unwind_orc.c:494 Code: c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 48 83 e0 fe 49 8d 5c 45 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 <84> c0 75 34 48 63 2b 48 01 dd 48 89 ef 4c 89 f6 e8 30 da 54 00 48 RSP: 0018:ffffc90003907828 EFLAGS: 00000a06 RAX: 0000000000000000 RBX: ffffffff9021c0d8 RCX: dffffc0000000000 RDX: ffff88807aadda00 RSI: 00000000001ade7f RDI: 00000000001ade80 RBP: 00000000000a813b R08: ffffffff8141424e R09: ffffc900039079f0 R10: 0000000000000003 R11: ffffffff8181fb90 R12: ffffffff9021c0d8 R13: ffffffff9021c0d8 R14: ffffffff8b813ba4 R15: ffffffff9021c0d8 arch_stack_walk+0x151/0x1b0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:312 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3798 [inline] slab_alloc_node mm/slub.c:3845 [inline] kmem_cache_alloc+0x174/0x340 mm/slub.c:3852 getname_flags+0xbd/0x4f0 fs/namei.c:139 user_path_at_empty+0x2c/0x60 fs/namei.c:2920 do_readlinkat+0x118/0x3b0 fs/stat.c:499 __do_sys_readlink fs/stat.c:532 [inline] __se_sys_readlink fs/stat.c:529 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:529 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1e8f717d47 Code: 73 01 c3 48 8b 0d e1 90 0d 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 59 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b1 90 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffd6dcfb088 EFLAGS: 00000246 ORIG_RAX: 0000000000000059 RAX: ffffffffffffffda RBX: 00007ffd6dcfb098 RCX: 00007f1e8f717d47 RDX: 0000000000000400 RSI: 00007ffd6dcfb098 RDI: 00007ffd6dcfb578 RBP: 0000000000000400 R08: 0000558e756f4ba4 R09: 0000000000000000 R10: 0000000000000812 R11: 0000000000000246 R12: 00007ffd6dcfb578 R13: 00007ffd6dcfb4e8 R14: 0000558e756e1910 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: c1 48 c1 f9 rorl $0xf9,-0x3f(%rax) 4: 02 48 c1 add -0x3f(%rax),%cl 7: e8 3f 48 01 c8 call 0xc801484b c: 48 83 e0 fe and $0xfffffffffffffffe,%rax 10: 49 8d 5c 45 00 lea 0x0(%r13,%rax,2),%rbx 15: 48 89 d8 mov %rbx,%rax 18: 48 c1 e8 03 shr $0x3,%rax 1c: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 23: fc ff df 26: 0f b6 04 08 movzbl (%rax,%rcx,1),%eax * 2a: 84 c0 test %al,%al <-- trapping instruction 2c: 75 34 jne 0x62 2e: 48 63 2b movslq (%rbx),%rbp 31: 48 01 dd add %rbx,%rbp 34: 48 89 ef mov %rbp,%rdi 37: 4c 89 f6 mov %r14,%rsi 3a: e8 30 da 54 00 call 0x54da6f 3f: 48 rex.W