============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- udevd/5158 is trying to acquire lock: ffff888021208218 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x171/0x5f0 kernel/bpf/queue_stack_maps.c:210 but task is already holding lock: ffff88807d025218 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x171/0x5f0 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 6 locks held by udevd/5158: #0: ffff88802c726418 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:403 #1: ffff8881413604e0 (kn->active#5){.+.+}-{0:0}, at: kernfs_fop_open+0x8e/0xcc0 fs/kernfs/file.c:668 #2: ffff888019e556e8 (&kernfs_locks->open_file_mutex[count]){+.+.}-{3:3}, at: kernfs_open_file_mutex_lock fs/kernfs/file.c:56 [inline] #2: ffff888019e556e8 (&kernfs_locks->open_file_mutex[count]){+.+.}-{3:3}, at: kernfs_get_open_node fs/kernfs/file.c:587 [inline] #2: ffff888019e556e8 (&kernfs_locks->open_file_mutex[count]){+.+.}-{3:3}, at: kernfs_fop_open+0x6fd/0xcc0 fs/kernfs/file.c:760 #3: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #3: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #3: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #3: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xde/0x3c0 kernel/trace/bpf_trace.c:2361 #4: ffff88807d025218 (&qs->lock){-.-.}-{2:2}, at: queue_stack_map_push_elem+0x171/0x5f0 kernel/bpf/queue_stack_maps.c:210 #5: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #5: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #5: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline] #5: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xde/0x3c0 kernel/trace/bpf_trace.c:2361 stack backtrace: CPU: 0 PID: 5158 Comm: udevd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x5d40/0x7c80 kernel/locking/lockdep.c:5137 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162 queue_stack_map_push_elem+0x171/0x5f0 kernel/bpf/queue_stack_maps.c:210 bpf_prog_216c997a1f42e404+0x3f/0x43 bpf_dispatcher_nop_func include/linux/bpf.h:1223 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361 __bpf_trace_contention_end+0xdd/0x130 include/trace/events/lock.h:122 __traceiter_contention_end+0x78/0xb0 include/trace/events/lock.h:122 trace_contention_end+0xe6/0x110 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x7ec/0x9d0 kernel/locking/qspinlock.c:560 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [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+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xb4/0xf0 kernel/locking/spinlock.c:162 queue_stack_map_push_elem+0x171/0x5f0 kernel/bpf/queue_stack_maps.c:210 bpf_prog_216c997a1f42e404+0x3f/0x43 bpf_dispatcher_nop_func include/linux/bpf.h:1223 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361 __bpf_trace_contention_end+0xdd/0x130 include/trace/events/lock.h:122 __traceiter_contention_end+0x78/0xb0 include/trace/events/lock.h:122 trace_contention_end+0xc5/0xe0 include/trace/events/lock.h:122 __mutex_lock_common kernel/locking/mutex.c:612 [inline] __mutex_lock+0x2fa/0xcc0 kernel/locking/mutex.c:747 kernfs_open_file_mutex_lock fs/kernfs/file.c:56 [inline] kernfs_get_open_node fs/kernfs/file.c:587 [inline] kernfs_fop_open+0x6fd/0xcc0 fs/kernfs/file.c:760 do_dentry_open+0x8c6/0x1500 fs/open.c:929 do_open fs/namei.c:3632 [inline] path_openat+0x274b/0x3190 fs/namei.c:3789 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419 do_sys_open fs/open.c:1434 [inline] __do_sys_openat fs/open.c:1450 [inline] __se_sys_openat fs/open.c:1445 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1445 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f916b2a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007fff78fc6120 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f916baab880 RCX: 00007f916b2a7407 RDX: 0000000000080241 RSI: 00007fff78fc6590 RDI: ffffffffffffff9c RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000001b6 R11: 0000000000000202 R12: 0000563d99743dfc R13: 0000563d99743dfc R14: 0000000000000001 R15: 00007fff78fc64a0