FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 1
======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-11993-g3efc57369a0c #0 Not tainted
------------------------------------------------------
syz-executor330/5220 is trying to acquire lock:
ffffffff8e813320 (console_owner){-...}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:342 [inline]
ffffffff8e813320 (console_owner){-...}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:267 [inline]
ffffffff8e813320 (console_owner){-...}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
ffffffff8e813320 (console_owner){-...}-{0:0}, at: console_flush_all+0x1a3/0xeb0 kernel/printk/printk.c:3157

but task is already holding lock:
ffff8880b873ea58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:593

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&rq->__lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:593
       raw_spin_rq_lock kernel/sched/sched.h:1505 [inline]
       task_rq_lock+0xc6/0x360 kernel/sched/core.c:695
       cgroup_move_task+0x92/0x2d0 kernel/sched/psi.c:1161
       css_set_move_task+0x72e/0x950 kernel/cgroup/cgroup.c:898
       cgroup_post_fork+0x256/0x880 kernel/cgroup/cgroup.c:6692
       copy_process+0x39e9/0x3d50 kernel/fork.c:2601
       kernel_clone+0x223/0x880 kernel/fork.c:2787
       user_mode_thread+0x132/0x1a0 kernel/fork.c:2865
       rest_init+0x23/0x300 init/main.c:712
       start_kernel+0x47f/0x500 init/main.c:1105
       x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507
       x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:488
       common_startup_64+0x13e/0x147

-> #4 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
       try_to_wake_up+0xb0/0x1480 kernel/sched/core.c:4154
       create_worker+0x507/0x720 kernel/workqueue.c:2825
       workqueue_init+0x520/0x8a0 kernel/workqueue.c:7902
       kernel_init_freeable+0x3fe/0x5d0 init/main.c:1564
       kernel_init+0x1d/0x2b0 init/main.c:1469
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #3 (&pool->lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       __queue_work+0x759/0xf50
       queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390
       queue_work include/linux/workqueue.h:662 [inline]
       rpm_suspend+0xe70/0x1730 drivers/base/power/runtime.c:662
       __pm_runtime_idle+0x131/0x1a0 drivers/base/power/runtime.c:1104
       pm_runtime_put include/linux/pm_runtime.h:448 [inline]
       __device_attach+0x3e5/0x520 drivers/base/dd.c:1048
       bus_probe_device+0x189/0x260 drivers/base/bus.c:534
       device_add+0x856/0xbf0 drivers/base/core.c:3675
       serial_base_port_add+0x2b6/0x3f0 drivers/tty/serial/serial_base_bus.c:179
       serial_core_port_device_add drivers/tty/serial/serial_core.c:3370 [inline]
       serial_core_register_port+0x377/0x2870 drivers/tty/serial/serial_core.c:3411
       serial8250_register_8250_port+0x1545/0x1ec0 drivers/tty/serial/8250/8250_core.c:820
       serial_pnp_probe+0x4f9/0x9d0 drivers/tty/serial/8250/8250_pnp.c:490
       pnp_device_probe+0x2ba/0x460 drivers/pnp/driver.c:111
       really_probe+0x2b8/0xad0 drivers/base/dd.c:658
       __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
       driver_probe_device+0x50/0x430 drivers/base/dd.c:830
       __driver_attach+0x45f/0x710 drivers/base/dd.c:1216
       bus_for_each_dev+0x239/0x2b0 drivers/base/bus.c:370
       bus_add_driver+0x346/0x670 drivers/base/bus.c:675
       driver_register+0x23a/0x320 drivers/base/driver.c:246
       serial8250_init+0xc1/0x1c0 drivers/tty/serial/8250/8250_platform.c:324
       do_one_initcall+0x248/0x880 init/main.c:1269
       do_initcall_level+0x157/0x210 init/main.c:1331
       do_initcalls+0x3f/0x80 init/main.c:1347
       kernel_init_freeable+0x435/0x5d0 init/main.c:1580
       kernel_init+0x1d/0x2b0 init/main.c:1469
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #2 (&dev->power.lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       __pm_runtime_resume+0x112/0x180 drivers/base/power/runtime.c:1171
       pm_runtime_get include/linux/pm_runtime.h:396 [inline]
       __uart_start+0x17c/0x450 drivers/tty/serial/serial_core.c:148
       uart_write+0x280/0xa40 drivers/tty/serial/serial_core.c:635
       process_output_block drivers/tty/n_tty.c:574 [inline]
       n_tty_write+0xd62/0x1230 drivers/tty/n_tty.c:2389
       iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
       file_tty_write+0x546/0x9b0 drivers/tty/tty_io.c:1090
       new_sync_write fs/read_write.c:590 [inline]
       vfs_write+0xa6d/0xc90 fs/read_write.c:683
       ksys_write+0x183/0x2b0 fs/read_write.c:736
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&port_lock_key){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       uart_port_lock_irqsave include/linux/serial_core.h:711 [inline]
       serial8250_console_write+0x1a7/0x1ed0 drivers/tty/serial/8250/8250_port.c:3352
       console_emit_next_record kernel/printk/printk.c:3092 [inline]
       console_flush_all+0x86b/0xeb0 kernel/printk/printk.c:3180
       __console_flush_and_unlock kernel/printk/printk.c:3239 [inline]
       console_unlock+0x14f/0x3b0 kernel/printk/printk.c:3279
       vprintk_emit+0x730/0xa10 kernel/printk/printk.c:2407
       _printk+0xd5/0x120 kernel/printk/printk.c:2432
       register_console+0xbf5/0xfd0 kernel/printk/printk.c:4069
       univ8250_console_init+0x52/0x90 drivers/tty/serial/8250/8250_core.c:513
       console_init+0x1b8/0x6f0 kernel/printk/printk.c:4262
       start_kernel+0x2d8/0x500 init/main.c:1040
       x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507
       x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:488
       common_startup_64+0x13e/0x147

-> #0 (console_owner){-...}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3158 [inline]
       check_prevs_add kernel/locking/lockdep.c:3277 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
       __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       console_lock_spinning_enable kernel/printk/printk.c:1905 [inline]
       console_emit_next_record kernel/printk/printk.c:3086 [inline]
       console_flush_all+0x7f8/0xeb0 kernel/printk/printk.c:3180
       __console_flush_and_unlock kernel/printk/printk.c:3239 [inline]
       console_unlock+0x14f/0x3b0 kernel/printk/printk.c:3279
       vprintk_emit+0x730/0xa10 kernel/printk/printk.c:2407
       _printk+0xd5/0x120 kernel/printk/printk.c:2432
       fail_dump lib/fault-inject.c:46 [inline]
       should_fail_ex+0x391/0x4e0 lib/fault-inject.c:154
       strncpy_from_user+0x36/0x250 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
       ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
       bpf_probe_read_compat_str+0xe9/0x180 kernel/trace/bpf_trace.c:306
       bpf_prog_e42f6260c1b72fb3+0x3e/0x40
       bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
       __bpf_prog_run include/linux/filter.h:701 [inline]
       bpf_prog_run include/linux/filter.h:708 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
       bpf_trace_run4+0x334/0x590 kernel/trace/bpf_trace.c:2361
       __traceiter_sched_switch+0x98/0xd0 include/trace/events/sched.h:222
       trace_sched_switch include/trace/events/sched.h:222 [inline]
       __schedule+0x22f8/0x4ae0 kernel/sched/core.c:6672
       __schedule_loop kernel/sched/core.c:6752 [inline]
       schedule+0x14b/0x320 kernel/sched/core.c:6767
       ptrace_stop+0x5b4/0x940 kernel/signal.c:2357
       ptrace_do_notify kernel/signal.c:2394 [inline]
       ptrace_notify+0x255/0x380 kernel/signal.c:2406
       ptrace_report_syscall include/linux/ptrace.h:415 [inline]
       ptrace_report_syscall_entry include/linux/ptrace.h:452 [inline]
       syscall_trace_enter+0x5d/0x150 kernel/entry/common.c:45
       syscall_enter_from_user_mode_work include/linux/entry-common.h:168 [inline]
       syscall_enter_from_user_mode include/linux/entry-common.h:198 [inline]
       do_syscall_64+0xcc/0x230 arch/x86/entry/common.c:79
       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 ***

4 locks held by syz-executor330/5220:
 #0: ffff8880b873ea58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:593
 #1: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #1: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2317 [inline]
 #1: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x244/0x590 kernel/trace/bpf_trace.c:2361
 #2: ffffffff8e813380 (console_lock){+.+.}-{0:0}, at: _printk+0xd5/0x120 kernel/printk/printk.c:2432
 #3: ffffffff8e812f90 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:342 [inline]
 #3: ffffffff8e812f90 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:267 [inline]
 #3: ffffffff8e812f90 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
 #3: ffffffff8e812f90 (console_srcu){....}-{0:0}, at: console_flush_all+0x1a3/0xeb0 kernel/printk/printk.c:3157

stack backtrace:
CPU: 1 UID: 0 PID: 5220 Comm: syz-executor330 Not tainted 6.11.0-syzkaller-11993-g3efc57369a0c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
 check_prev_add kernel/locking/lockdep.c:3158 [inline]
 check_prevs_add kernel/locking/lockdep.c:3277 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 console_lock_spinning_enable kernel/printk/printk.c:1905 [inline]
 console_emit_next_record kernel/printk/printk.c:3086 [inline]
 console_flush_all+0x7f8/0xeb0 kernel/printk/printk.c:3180
 __console_flush_and_unlock kernel/printk/printk.c:3239 [inline]
 console_unlock+0x14f/0x3b0 kernel/printk/printk.c:3279
 vprintk_emit+0x730/0xa10 kernel/printk/printk.c:2407
 _printk+0xd5/0x120 kernel/printk/printk.c:2432
 fail_dump lib/fault-inject.c:46 [inline]
 should_fail_ex+0x391/0x4e0 lib/fault-inject.c:154
 strncpy_from_user+0x36/0x250 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
 bpf_probe_read_compat_str+0xe9/0x180 kernel/trace/bpf_trace.c:306
 bpf_prog_e42f6260c1b72fb3+0x3e/0x40
 bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
 __bpf_prog_run include/linux/filter.h:701 [inline]
 bpf_prog_run include/linux/filter.h:708 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
 bpf_trace_run4+0x334/0x590 kernel/trace/bpf_trace.c:2361
 __traceiter_sched_switch+0x98/0xd0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x22f8/0x4ae0 kernel/sched/core.c:6672
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6767
 ptrace_stop+0x5b4/0x940 kernel/signal.c:2357
 ptrace_do_notify kernel/signal.c:2394 [inline]
 ptrace_notify+0x255/0x380 kernel/signal.c:2406
 ptrace_report_syscall include/linux/ptrace.h:415 [inline]
 ptrace_report_syscall_entry include/linux/ptrace.h:452 [inline]
 syscall_trace_enter+0x5d/0x150 kernel/entry/common.c:45
 syscall_enter_from_user_mode_work include/linux/entry-common.h:168 [inline]
 syscall_enter_from_user_mode include/linux/entry-common.h:198 [inline]
 do_syscall_64+0xcc/0x230 arch/x86/entry/common.c:79
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4acaaaea99
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 a1 1a 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdb963eea8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffdb963eec0 RCX: 00007f4acaaaea99
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffdb963ec47 R09: 0000000000000140
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
CPU: 1 UID: 0 PID: 5220 Comm: syz-executor330 Not tainted 6.11.0-syzkaller-11993-g3efc57369a0c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:53 [inline]
 should_fail_ex+0x3b0/0x4e0 lib/fault-inject.c:154
 strncpy_from_user+0x36/0x250 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
 bpf_probe_read_compat_str+0xe9/0x180 kernel/trace/bpf_trace.c:306
 bpf_prog_e42f6260c1b72fb3+0x3e/0x40
 bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
 __bpf_prog_run include/linux/filter.h:701 [inline]
 bpf_prog_run include/linux/filter.h:708 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
 bpf_trace_run4+0x334/0x590 kernel/trace/bpf_trace.c:2361
 __traceiter_sched_switch+0x98/0xd0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x22f8/0x4ae0 kernel/sched/core.c:6672
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6767
 ptrace_stop+0x5b4/0x940 kernel/signal.c:2357
 ptrace_do_notify kernel/signal.c:2394 [inline]
 ptrace_notify+0x255/0x380 kernel/signal.c:2406
 ptrace_report_syscall include/linux/ptrace.h:415 [inline]
 ptrace_report_syscall_entry include/linux/ptrace.h:452 [inline]
 syscall_trace_enter+0x5d/0x150 kernel/entry/common.c:45
 syscall_enter_from_user_mode_work include/linux/entry-common.h:168 [inline]
 syscall_enter_from_user_mode include/linux/entry-common.h:198 [inline]
 do_syscall_64+0xcc/0x230 arch/x86/entry/common.c:79
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4acaaaea99
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 a1 1a 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdb963eea8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffdb963eec0 RCX: 00007f4acaaaea99
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffdb963ec47 R09: 0000000000000140
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Zero length message leads to an empty skb