FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.3.6525/32528 is trying to acquire lock: ffffffff8df35940 (console_owner){-.-.}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline] ffffffff8df35940 (console_owner){-.-.}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:409 [inline] ffffffff8df35940 (console_owner){-.-.}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline] ffffffff8df35940 (console_owner){-.-.}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3192 [inline] ffffffff8df35940 (console_owner){-.-.}-{0:0}, at: console_flush_all+0x11a/0xb00 kernel/printk/printk.c:3289 but task is already holding lock: ffff8880b863a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:647 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:1580 [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:948 cgroup_post_fork+0x1ef/0x7a0 kernel/cgroup/cgroup.c:6910 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 csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xcca/0x1260 kernel/smp.c:877 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline] flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103 wp_page_copy mm/memory.c:3785 [inline] do_wp_page+0x1bb1/0x5810 mm/memory.c:4180 handle_pte_fault mm/memory.c:6289 [inline] __handle_mm_fault mm/memory.c:6411 [inline] handle_mm_fault+0x14c5/0x32b0 mm/memory.c:6580 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 -> #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 native_irq_enable arch/x86/include/asm/irqflags.h:42 [inline] arch_local_irq_enable arch/x86/include/asm/irqflags.h:119 [inline] raw_spin_rq_unlock_irq kernel/sched/sched.h:1592 [inline] finish_lock_switch kernel/sched/core.c:4999 [inline] finish_task_switch+0x242/0x940 kernel/sched/core.c:5116 context_switch kernel/sched/core.c:5263 [inline] __schedule+0x14a3/0x4fd0 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x165/0x360 kernel/sched/core.c:6964 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_lock_spinning_enable kernel/printk/printk.c:1900 [inline] console_emit_next_record kernel/printk/printk.c:3123 [inline] console_flush_one_record kernel/printk/printk.c:3215 [inline] console_flush_all+0x6bc/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 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_trace_copy_string kernel/bpf/helpers.c:755 [inline] bpf_bprintf_prepare+0xbbc/0x13d0 kernel/bpf/helpers.c:976 ____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline] bpf_trace_printk+0xdb/0x190 kernel/trace/bpf_trace.c:362 bpf_prog_930ede9872f2967c+0x3e/0x44 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_contention_begin+0xdc/0x130 include/trace/events/lock.h:95 __do_trace_contention_begin include/trace/events/lock.h:95 [inline] trace_contention_begin+0xfe/0x120 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0xf0/0xb60 kernel/locking/qspinlock.c:219 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116 raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:647 raw_spin_rq_lock kernel/sched/sched.h:1580 [inline] rq_lock kernel/sched/sched.h:1907 [inline] __schedule+0x3c4/0x4fd0 kernel/sched/core.c:6772 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7194 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 proc_fail_nth_write+0x144/0x200 fs/proc/base.c:-1 vfs_write+0x27e/0xb30 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:738 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 *** 6 locks held by syz.3.6525/32528: #0: ffff8880517ead38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1255 #1: ffff888051514420 (sb_writers#3){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline] #1: ffff888051514420 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x211/0xb30 fs/read_write.c:682 #2: ffff8880b863a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:647 #3: ffffffff8df41ae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8df41ae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #3: ffffffff8df41ae0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline] #3: ffffffff8df41ae0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4c0 kernel/trace/bpf_trace.c:2116 #4: ffffffff8df359a0 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x120 kernel/printk/printk.c:2451 #5: ffffffff8de1d258 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline] #5: ffffffff8de1d258 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:409 [inline] #5: ffffffff8de1d258 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline] #5: ffffffff8de1d258 (console_srcu){....}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3192 [inline] #5: ffffffff8de1d258 (console_srcu){....}-{0:0}, at: console_flush_all+0x11a/0xb00 kernel/printk/printk.c:3289 stack backtrace: CPU: 1 UID: 0 PID: 32528 Comm: syz.3.6525 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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_lock_spinning_enable kernel/printk/printk.c:1900 [inline] console_emit_next_record kernel/printk/printk.c:3123 [inline] console_flush_one_record kernel/printk/printk.c:3215 [inline] console_flush_all+0x6bc/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 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_trace_copy_string kernel/bpf/helpers.c:755 [inline] bpf_bprintf_prepare+0xbbc/0x13d0 kernel/bpf/helpers.c:976 ____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline] bpf_trace_printk+0xdb/0x190 kernel/trace/bpf_trace.c:362 bpf_prog_930ede9872f2967c+0x3e/0x44 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_contention_begin+0xdc/0x130 include/trace/events/lock.h:95 __do_trace_contention_begin include/trace/events/lock.h:95 [inline] trace_contention_begin+0xfe/0x120 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0xf0/0xb60 kernel/locking/qspinlock.c:219 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116 raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:647 raw_spin_rq_lock kernel/sched/sched.h:1580 [inline] rq_lock kernel/sched/sched.h:1907 [inline] __schedule+0x3c4/0x4fd0 kernel/sched/core.c:6772 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7194 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__refcount_sub_and_test include/linux/refcount.h:394 [inline] RIP: 0010:__refcount_dec_and_test include/linux/refcount.h:432 [inline] RIP: 0010:refcount_dec_and_test include/linux/refcount.h:450 [inline] RIP: 0010:put_task_struct include/linux/sched/task.h:130 [inline] RIP: 0010:proc_fail_nth_write+0x144/0x200 fs/proc/base.c:1471 Code: 4c 89 ff be 04 00 00 00 e8 e9 af c6 ff 41 bc ff ff ff ff f0 45 0f c1 66 28 bf 01 00 00 00 44 89 e6 e8 90 8e 60 ff 41 83 fc 01 <75> 2b e8 45 8a 60 ff 49 81 c6 c0 17 00 00 4c 89 f7 48 c7 c6 f0 b5 RSP: 0018:ffffc90003e5fc00 EFLAGS: 00000202 RAX: ffffffff82608330 RBX: 0000000000000001 RCX: 0000000000000000 RDX: ffff88802d251e80 RSI: 0000000000000002 RDI: 0000000000000001 RBP: ffffc90003e5fc90 R08: ffff88802d251eab R09: 1ffff11005a4a3d5 R10: dffffc0000000000 R11: ffffed1005a4a3d6 R12: 0000000000000002 R13: 1ffff920007cbf80 R14: ffff88802d251e80 R15: ffff88802d251ea8 vfs_write+0x27e/0xb30 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:738 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: 0033:0x7f21a7d8e1ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007f21a8b51030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f21a7d8e1ff RDX: 0000000000000001 RSI: 00007f21a8b51090 RDI: 0000000000000009 RBP: 00007f21a8b51090 R08: 0000000000000000 R09: 00007f21a8b50df7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f21a7fe6128 R14: 00007f21a7fe6090 R15: 00007fff511ec478 CPU: 1 UID: 0 PID: 32528 Comm: syz.3.6525 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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_trace_copy_string kernel/bpf/helpers.c:755 [inline] bpf_bprintf_prepare+0xbbc/0x13d0 kernel/bpf/helpers.c:976 ____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline] bpf_trace_printk+0xdb/0x190 kernel/trace/bpf_trace.c:362 bpf_prog_930ede9872f2967c+0x3e/0x44 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_contention_begin+0xdc/0x130 include/trace/events/lock.h:95 __do_trace_contention_begin include/trace/events/lock.h:95 [inline] trace_contention_begin+0xfe/0x120 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0xf0/0xb60 kernel/locking/qspinlock.c:219 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116 raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:647 raw_spin_rq_lock kernel/sched/sched.h:1580 [inline] rq_lock kernel/sched/sched.h:1907 [inline] __schedule+0x3c4/0x4fd0 kernel/sched/core.c:6772 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7194 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__refcount_sub_and_test include/linux/refcount.h:394 [inline] RIP: 0010:__refcount_dec_and_test include/linux/refcount.h:432 [inline] RIP: 0010:refcount_dec_and_test include/linux/refcount.h:450 [inline] RIP: 0010:put_task_struct include/linux/sched/task.h:130 [inline] RIP: 0010:proc_fail_nth_write+0x144/0x200 fs/proc/base.c:1471 Code: 4c 89 ff be 04 00 00 00 e8 e9 af c6 ff 41 bc ff ff ff ff f0 45 0f c1 66 28 bf 01 00 00 00 44 89 e6 e8 90 8e 60 ff 41 83 fc 01 <75> 2b e8 45 8a 60 ff 49 81 c6 c0 17 00 00 4c 89 f7 48 c7 c6 f0 b5 RSP: 0018:ffffc90003e5fc00 EFLAGS: 00000202 RAX: ffffffff82608330 RBX: 0000000000000001 RCX: 0000000000000000 RDX: ffff88802d251e80 RSI: 0000000000000002 RDI: 0000000000000001 RBP: ffffc90003e5fc90 R08: ffff88802d251eab R09: 1ffff11005a4a3d5 R10: dffffc0000000000 R11: ffffed1005a4a3d6 R12: 0000000000000002 R13: 1ffff920007cbf80 R14: ffff88802d251e80 R15: ffff88802d251ea8 vfs_write+0x27e/0xb30 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:738 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: 0033:0x7f21a7d8e1ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007f21a8b51030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f21a7d8e1ff RDX: 0000000000000001 RSI: 00007f21a8b51090 RDI: 0000000000000009 RBP: 00007f21a8b51090 R08: 0000000000000000 R09: 00007f21a8b50df7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007f21a7fe6128 R14: 00007f21a7fe6090 R15: 00007fff511ec478 ---------------- Code disassembly (best guess): 0: 4c 89 ff mov %r15,%rdi 3: be 04 00 00 00 mov $0x4,%esi 8: e8 e9 af c6 ff call 0xffc6aff6 d: 41 bc ff ff ff ff mov $0xffffffff,%r12d 13: f0 45 0f c1 66 28 lock xadd %r12d,0x28(%r14) 19: bf 01 00 00 00 mov $0x1,%edi 1e: 44 89 e6 mov %r12d,%esi 21: e8 90 8e 60 ff call 0xff608eb6 26: 41 83 fc 01 cmp $0x1,%r12d * 2a: 75 2b jne 0x57 <-- trapping instruction 2c: e8 45 8a 60 ff call 0xff608a76 31: 49 81 c6 c0 17 00 00 add $0x17c0,%r14 38: 4c 89 f7 mov %r14,%rdi 3b: 48 rex.W 3c: c7 .byte 0xc7 3d: c6 (bad) 3e: f0 lock 3f: b5 .byte 0xb5