FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.4.1033/9379 is trying to acquire lock:
ffffffff8df35920 (console_owner){-.-.}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:2024 [inline]
ffffffff8df35920 (console_owner){-.-.}-{0:0}, at: vprintk_emit+0x2c5/0x550 kernel/printk/printk.c:2425

but task is already holding lock:
ffff8880b873a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&rq->__lock){-.-.}-{2:2}:
       _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639
       raw_spin_rq_lock kernel/sched/sched.h:1558 [inline]
       task_rq_lock+0xbc/0x470 kernel/sched/core.c:739
       cgroup_move_task+0x92/0x2a0 kernel/sched/psi.c:1170
       css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:951
       cgroup_post_fork+0x1ef/0x7a0 kernel/cgroup/cgroup.c:6913
       copy_process+0x3614/0x3950 kernel/fork.c:2465
       kernel_clone+0x21e/0x820 kernel/fork.c:2651
       user_mode_thread+0xdd/0x140 kernel/fork.c:2727
       rest_init+0x23/0x300 init/main.c:722
       start_kernel+0x381/0x3d0 init/main.c:1206
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x147

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
       try_to_wake_up+0x67/0x12b0 kernel/sched/core.c:4106
       __wake_up_common kernel/sched/wait.c:108 [inline]
       __wake_up_common_lock+0x137/0x1f0 kernel/sched/wait.c:125
       tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x217/0x970 kernel/irq/handle.c:211
       handle_irq_event_percpu kernel/irq/handle.c:248 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:265
       handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855
       generic_handle_irq_desc include/linux/irqdesc.h:172 [inline]
       handle_irq arch/x86/kernel/irq.c:255 [inline]
       call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:326
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:319
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
       lock_release+0x18/0x3b0 kernel/locking/lockdep.c:5876
       rcu_lock_release include/linux/rcupdate.h:341 [inline]
       rcu_read_unlock include/linux/rcupdate.h:897 [inline]
       class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
       unwind_next_frame+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695
       arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
       stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
       kasan_save_stack mm/kasan/common.c:57 [inline]
       kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
       kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
       poison_slab_object mm/kasan/common.c:253 [inline]
       __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
       kasan_slab_free include/linux/kasan.h:235 [inline]
       slab_free_hook mm/slub.c:2540 [inline]
       slab_free mm/slub.c:6670 [inline]
       kfree+0x1c0/0x660 mm/slub.c:6878
       tomoyo_realpath_from_path+0x598/0x5d0 security/tomoyo/realpath.c:286
       tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
       tomoyo_path_number_perm+0x1e8/0x5a0 security/tomoyo/file.c:723
       security_file_ioctl+0xcb/0x2d0 security/security.c:2435
       __do_sys_ioctl fs/ioctl.c:591 [inline]
       __se_sys_ioctl+0x47/0x170 fs/ioctl.c:583
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&tty->write_wait){-.-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       __wake_up_common_lock+0x2f/0x1f0 kernel/sched/wait.c:124
       tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x217/0x970 kernel/irq/handle.c:211
       handle_irq_event_percpu kernel/irq/handle.c:248 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:265
       handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855
       generic_handle_irq_desc include/linux/irqdesc.h:172 [inline]
       handle_irq arch/x86/kernel/irq.c:255 [inline]
       call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:326
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:319
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
       __schedule+0x14cd/0x4fd0 kernel/sched/core.c:6874
       __schedule_loop kernel/sched/core.c:6945 [inline]
       schedule+0x165/0x360 kernel/sched/core.c:6960
       worker_thread+0xa82/0xda0 kernel/workqueue.c:3436
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

-> #1 (&port_lock_key){-.-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
       serial8250_console_write+0x155/0x1b60 drivers/tty/serial/8250/8250_port.c:3301
       console_emit_next_record kernel/printk/printk.c:3129 [inline]
       console_flush_one_record kernel/printk/printk.c:3215 [inline]
       console_flush_all+0x713/0xb00 kernel/printk/printk.c:3289
       __console_flush_and_unlock kernel/printk/printk.c:3319 [inline]
       console_unlock+0xbb/0x190 kernel/printk/printk.c:3359
       vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2426
       _printk+0xcf/0x120 kernel/printk/printk.c:2451
       register_console+0xa8b/0xf90 kernel/printk/printk.c:4170
       univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:515
       console_init+0xfc/0x3f0 kernel/printk/printk.c:4369
       start_kernel+0x227/0x3d0 init/main.c:1143
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x147

-> #0 (console_owner){-.-.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
       console_trylock_spinning kernel/printk/printk.c:2024 [inline]
       vprintk_emit+0x2e1/0x550 kernel/printk/printk.c:2425
       _printk+0xcf/0x120 kernel/printk/printk.c:2451
       fail_dump lib/fault-inject.c:66 [inline]
       should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
       strncpy_from_user+0x36/0x2c0 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
       ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
       bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
       bpf_prog_d359f1fa6cfa10c1+0x78/0x80
       bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline]
       __bpf_prog_run include/linux/filter.h:723 [inline]
       bpf_prog_run include/linux/filter.h:730 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
       bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
       __bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:39
       __do_trace_tlb_flush include/trace/events/tlb.h:39 [inline]
       trace_tlb_flush+0xff/0x120 include/trace/events/tlb.h:39
       switch_mm_irqs_off+0x4cc/0x700 arch/x86/mm/tlb.c:-1
       context_switch kernel/sched/core.c:5235 [inline]
       __schedule+0xfdb/0x4fd0 kernel/sched/core.c:6863
       preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047
       preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
       __local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457
       spin_unlock_bh include/linux/spinlock.h:396 [inline]
       __ip6_del_rt+0xa1/0x180 net/ipv6/route.c:3977
       ip6_del_rt+0xb3/0x100 net/ipv6/route.c:3991
       __ipv6_ifa_notify+0x5b7/0xaa0 net/ipv6/addrconf.c:6310
       ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline]
       ipv6_del_addr+0x678/0x8a0 net/ipv6/addrconf.c:1337
       inet6_addr_del+0x473/0x640 net/ipv6/addrconf.c:3115
       addrconf_del_ifaddr+0x113/0x160 net/ipv6/addrconf.c:3181
       inet6_ioctl+0x10f/0x280 net/ipv6/af_inet6.c:582
       sock_do_ioctl+0xdc/0x300 net/socket.c:1254
       sock_ioctl+0x576/0x790 net/socket.c:1375
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:597 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  console_owner --> &p->pi_lock --> &rq->__lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rq->__lock);
                               lock(&p->pi_lock);
                               lock(&rq->__lock);
  lock(console_owner);

 *** DEADLOCK ***

3 locks held by syz.4.1033/9379:
 #0: ffffffff8f311d88 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f311d88 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_del_ifaddr+0xfd/0x160 net/ipv6/addrconf.c:3180
 #1: ffff8880b873a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639
 #2: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #2: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
 #2: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4c0 kernel/trace/bpf_trace.c:2116

stack backtrace:
CPU: 1 UID: 0 PID: 9379 Comm: syz.4.1033 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
 console_trylock_spinning kernel/printk/printk.c:2024 [inline]
 vprintk_emit+0x2e1/0x550 kernel/printk/printk.c:2425
 _printk+0xcf/0x120 kernel/printk/printk.c:2451
 fail_dump lib/fault-inject.c:66 [inline]
 should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
 strncpy_from_user+0x36/0x2c0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
 bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
 bpf_prog_d359f1fa6cfa10c1+0x78/0x80
 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
 __bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:39
 __do_trace_tlb_flush include/trace/events/tlb.h:39 [inline]
 trace_tlb_flush+0xff/0x120 include/trace/events/tlb.h:39
 switch_mm_irqs_off+0x4cc/0x700 arch/x86/mm/tlb.c:-1
 context_switch kernel/sched/core.c:5235 [inline]
 __schedule+0xfdb/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 __ip6_del_rt+0xa1/0x180 net/ipv6/route.c:3977
 ip6_del_rt+0xb3/0x100 net/ipv6/route.c:3991
 __ipv6_ifa_notify+0x5b7/0xaa0 net/ipv6/addrconf.c:6310
 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline]
 ipv6_del_addr+0x678/0x8a0 net/ipv6/addrconf.c:1337
 inet6_addr_del+0x473/0x640 net/ipv6/addrconf.c:3115
 addrconf_del_ifaddr+0x113/0x160 net/ipv6/addrconf.c:3181
 inet6_ioctl+0x10f/0x280 net/ipv6/af_inet6.c:582
 sock_do_ioctl+0xdc/0x300 net/socket.c:1254
 sock_ioctl+0x576/0x790 net/socket.c:1375
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f3318f749
Code: Unable to access opcode bytes at 0x7f7f3318f71f.
RSP: 002b:00007f7f340a1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7f333e5fa0 RCX: 00007f7f3318f749
RDX: 0000200000000000 RSI: 0000000000008936 RDI: 0000000000000004
RBP: 00007f7f340a1090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f7f333e6038 R14: 00007f7f333e5fa0 R15: 00007ffdccde6fd8
 </TASK>
CPU: 1 UID: 0 PID: 9379 Comm: syz.4.1033 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x414/0x560 lib/fault-inject.c:174
 strncpy_from_user+0x36/0x2c0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
 bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
 bpf_prog_d359f1fa6cfa10c1+0x78/0x80
 bpf_dispatcher_nop_func include/linux/bpf.h:1378 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
 __bpf_trace_tlb_flush+0xf5/0x150 include/trace/events/tlb.h:39
 __do_trace_tlb_flush include/trace/events/tlb.h:39 [inline]
 trace_tlb_flush+0xff/0x120 include/trace/events/tlb.h:39
 switch_mm_irqs_off+0x4cc/0x700 arch/x86/mm/tlb.c:-1
 context_switch kernel/sched/core.c:5235 [inline]
 __schedule+0xfdb/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 __ip6_del_rt+0xa1/0x180 net/ipv6/route.c:3977
 ip6_del_rt+0xb3/0x100 net/ipv6/route.c:3991
 __ipv6_ifa_notify+0x5b7/0xaa0 net/ipv6/addrconf.c:6310
 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline]
 ipv6_del_addr+0x678/0x8a0 net/ipv6/addrconf.c:1337
 inet6_addr_del+0x473/0x640 net/ipv6/addrconf.c:3115
 addrconf_del_ifaddr+0x113/0x160 net/ipv6/addrconf.c:3181
 inet6_ioctl+0x10f/0x280 net/ipv6/af_inet6.c:582
 sock_do_ioctl+0xdc/0x300 net/socket.c:1254
 sock_ioctl+0x576/0x790 net/socket.c:1375
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f3318f749
Code: Unable to access opcode bytes at 0x7f7f3318f71f.
RSP: 002b:00007f7f340a1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7f333e5fa0 RCX: 00007f7f3318f749
RDX: 0000200000000000 RSI: 0000000000008936 RDI: 0000000000000004
RBP: 00007f7f340a1090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f7f333e6038 R14: 00007f7f333e5fa0 R15: 00007ffdccde6fd8
 </TASK>