======================================
| [    9.605920][  T179] softirqs last disabled at (25021): __irq_exit_rcu (kernel/softirq.c:679 kernel/softirq.c:519 kernel/softirq.c:767)
| [    9.605922][  T179] Preemption disabled at:
| [    9.605923][  T179] vprintk_emit (kernel/printk/printk.c:2471)
| [    9.605931][  T179] Tainted: [W]=WARN
[    9.605932][  T179] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[    9.605934][  T179] Call Trace:
[    9.605935][  T179]  <TASK>
[    9.605937][  T179]  dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
[    9.605942][  T179]  ? vprintk_emit (kernel/printk/printk.c:2471)
[    9.605944][  T179]  __might_resched.cold (kernel/sched/core.c:9234)
[    9.605948][  T179]  ? perf_trace_sched_switch (./include/linux/list.h:1037 (discriminator 3))
[    9.605952][  T179]  ? __kmalloc_noprof (./include/linux/sched/mm.h:317 mm/slub.c:4636 mm/slub.c:4974 mm/slub.c:5413 mm/slub.c:5439)
[    9.605957][  T179]  __kmalloc_noprof (./include/linux/sched/mm.h:322 (discriminator 2) mm/slub.c:4636 (discriminator 2) mm/slub.c:4974 (discriminator 2) mm/slub.c:5413 (discriminator 2) mm/slub.c:5439 (discriminator 2))
[    9.605959][  T179]  ? alloc_buf.isra.0 (./include/linux/slab.h:995 drivers/char/virtio_console.c:429)
[    9.605965][  T179]  ? do_raw_spin_unlock (./include/linux/instrumented.h:82 ./include/linux/atomic/atomic-instrumented.h:32 ./include/asm-generic/qspinlock.h:58 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141)
[    9.605967][  T179]  alloc_buf.isra.0 (./include/linux/slab.h:995 drivers/char/virtio_console.c:429)
[    9.605971][  T179]  put_chars (drivers/char/virtio_console.c:1176)
[    9.605974][  T179]  ? __send_to_port (drivers/char/virtio_console.c:654)
[    9.605978][  T179]  ? validate_chain (kernel/locking/lockdep.c:3817 (discriminator 2) kernel/locking/lockdep.c:3837 (discriminator 2) kernel/locking/lockdep.c:3892 (discriminator 2))
[    9.605983][  T179]  hvc_console_print (drivers/tty/hvc/hvc_console.c:177 (discriminator 2))
[    9.605990][  T179]  ? hvc_write (drivers/tty/hvc/hvc_console.c:501)
[    9.605993][  T179]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[    9.605996][  T179]  ? lock_acquire (./include/trace/events/lock.h:23 (discriminator 22) kernel/locking/lockdep.c:5871 (discriminator 22))
[    9.606000][  T179]  console_emit_next_record (kernel/printk/printk.c:3183)
[    9.606004][  T179]  ? devkmsg_read (./arch/x86/include/asm/atomic64_64.h:20)
[    9.606008][  T179]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[    9.606010][  T179]  ? lock_acquire (./include/trace/events/lock.h:23 (discriminator 22) kernel/locking/lockdep.c:5871 (discriminator 22))
[    9.606014][  T179]  console_flush_one_record (kernel/printk/printk.c:3268)
[    9.606017][  T179]  ? console_emit_next_record (kernel/printk/printk.c:3150)
[    9.606019][  T179]  ? __lock_acquire (kernel/locking/lockdep.c:5254)
[    9.606024][  T179]  console_unlock (kernel/printk/printk.c:3350 kernel/printk/printk.c:3380 kernel/printk/printk.c:3420)
[    9.606026][  T179]  ? console_flush_one_record (kernel/printk/printk.c:3316)
[    9.606028][  T179]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[    9.606029][  T179]  ? lock_acquire (kernel/locking/lockdep.c:5913)
[    9.606033][  T179]  ? __down_trylock_console_sem (kernel/printk/printk.c:334)
[    9.606035][  T179]  ? vprintk_emit (kernel/printk/printk.c:2478)
[    9.606038][  T179]  vprintk_emit (kernel/printk/printk.c:2479)
[    9.606041][  T179]  ? wake_up_klogd_work_func (kernel/printk/printk.c:4603 (discriminator 126))
[    9.606043][  T179]  ? find_held_lock (kernel/locking/lockdep.c:5367)
[    9.606047][  T179]  ? __lock_release.isra.0 (kernel/locking/lockdep.c:5554)
[    9.606049][  T179]  ? fast_dput (./include/linux/rcupdate.h:319 (discriminator 2) ./include/linux/rcupdate.h:880 (discriminator 2) fs/dcache.c:948 (discriminator 2))
[    9.606054][  T179]  ? cleanup_netconsole (./include/linux/list.h:99 (discriminator 2) ./include/linux/list.h:169 (discriminator 2) ./include/linux/list.h:206 (discriminator 2) ./include/linux/configfs.h:112 (discriminator 2) drivers/net/netconsole.c:1718 (discriminator 2)) netconsole
[    9.606058][  T179]  _printk (kernel/printk/printk.c:2504)
[    9.606062][  T179]  ? snapshot_read.cold (user.c:?)
[    9.606065][  T179]  ? __up_write (kernel/locking/rwsem.c:1422 (discriminator 1))
[    9.606068][  T179]  ? cleanup_netconsole (./include/linux/list.h:99 (discriminator 2) ./include/linux/list.h:169 (discriminator 2) ./include/linux/list.h:206 (discriminator 2) ./include/linux/configfs.h:112 (discriminator 2) drivers/net/netconsole.c:1718 (discriminator 2)) netconsole
[    9.606072][  T179]  ? configfs_register_subsystem (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:1383 fs/configfs/dir.c:173 fs/configfs/dir.c:171 fs/configfs/dir.c:1929)
[    9.606076][  T179] init_netconsole (drivers/net/netconsole.c:1286) netconsole
[    9.606079][  T179]  ? cleanup_netconsole (./include/linux/list.h:99 (discriminator 2) ./include/linux/list.h:169 (discriminator 2) ./include/linux/list.h:206 (discriminator 2) ./include/linux/configfs.h:112 (discriminator 2) drivers/net/netconsole.c:1718 (discriminator 2)) netconsole
[    9.606086][  T179]  ? cleanup_netconsole (./include/linux/list.h:99 (discriminator 2) ./include/linux/list.h:169 (discriminator 2) ./include/linux/list.h:206 (discriminator 2) ./include/linux/configfs.h:112 (discriminator 2) drivers/net/netconsole.c:1718 (discriminator 2)) netconsole
[    9.606088][  T179]  do_one_initcall (init/main.c:1357)
[    9.606092][  T179]  ? trace_event_raw_event_initcall_level (./include/trace/events/initcall.h:10)
[    9.606096][  T179]  ? do_init_module (./include/linux/slab.h:991 (discriminator 1) kernel/module/main.c:3105 (discriminator 1))
[    9.606099][  T179]  ? kasan_unpoison (mm/kasan/shadow.c:146 mm/kasan/shadow.c:178)
[    9.606104][  T179]  do_init_module (kernel/module/main.c:3117)
[    9.606107][  T179]  ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4488)
[    9.606111][  T179]  ? free_module (./include/trace/events/module.h:50 (discriminator 19))
[    9.606113][  T179]  ? kfree (./include/linux/kasan.h:235 mm/slub.c:2748 mm/slub.c:6499 mm/slub.c:6792)
[    9.606118][  T179]  load_module (kernel/module/main.c:3593)
[    9.606124][  T179]  ? layout_and_allocate.isra.0 (kernel/module/main.c:3016)
[    9.606127][  T179]  ? __ia32_sys_fsconfig (??:?)
[    9.606130][  T179]  ? ovl_real_file (fs/overlayfs/file.c:195)
[    9.606134][  T179]  ? backing_file_read_iter (fs/backing-file.c:211)
[    9.606138][  T179]  ? rcu_lockdep_current_cpu_online (kernel/rcu/tree.c:4116 (discriminator 3) kernel/rcu/tree.c:4108 (discriminator 3))
[    9.606141][  T179]  init_module_from_file (kernel/module/main.c:3790)
[    9.606144][  T179]  ? __do_sys_init_module (kernel/module/main.c:3664)
[    9.606151][  T179]  ? __rwlock_init (kernel/locking/spinlock_debug.c:48)
[    9.606154][  T179]  ? do_raw_spin_unlock (./include/linux/instrumented.h:82 ./include/linux/atomic/atomic-instrumented.h:32 ./include/asm-generic/qspinlock.h:58 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141)
[    9.606157][  T179]  idempotent_init_module (kernel/module/main.c:3802)
[    9.606160][  T179]  ? init_module_from_file (kernel/module/main.c:3791)
[    9.606165][  T179]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[    9.606167][  T179]  ? cap_capable (./include/trace/events/capability.h:26 (discriminator 22) security/commoncap.c:130 (discriminator 22))
[    9.606173][  T179]  __x64_sys_finit_module (kernel/module/main.c:3828 kernel/module/main.c:3812 kernel/module/main.c:3812)
[    9.606174][  T179]  ? trace_irq_enable.constprop.0 (./include/trace/events/preemptirq.h:40 (discriminator 22))
[    9.606178][  T179]  do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84)
[    9.606180][  T179]  ? exc_page_fault (arch/x86/mm/fault.c:1489 (discriminator 3) arch/x86/mm/fault.c:1536 (discriminator 3))
[    9.606182][  T179]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
[    9.606185][  T179] RIP: 0033:0x7f30a983f37d
[    9.606188][  T179] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 8b 0d 4b aa 0f 00 f7 d8 64 89 01 48
All code
========
   0:	ff c3                	inc    %ebx
   2:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
   9:	00 00 00 
   c:	90                   	nop
   d:	f3 0f 1e fa          	endbr64
  11:	48 89 f8             	mov    %rdi,%rax
  14:	48 89 f7             	mov    %rsi,%rdi
  17:	48 89 d6             	mov    %rdx,%rsi
  1a:	48 89 ca             	mov    %rcx,%rdx
  1d:	4d 89 c2             	mov    %r8,%r10
  20:	4d 89 c8             	mov    %r9,%r8
  23:	4c 8b 4c 24 08       	mov    0x8(%rsp),%r9
  28:	0f 05                	syscall
  2a:*	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax		<-- trapping instruction
  30:	73 01                	jae    0x33
  32:	c3                   	ret
  33:	48 8b 0d 4b aa 0f 00 	mov    0xfaa4b(%rip),%rcx        # 0xfaa85
  3a:	f7 d8                	neg    %eax
  3c:	64 89 01             	mov    %eax,%fs:(%rcx)
  3f:	48                   	rex.W

Code starting with the faulting instruction
===========================================
   0:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax
   6:	73 01                	jae    0x9
   8:	c3                   	ret
   9:	48 8b 0d 4b aa 0f 00 	mov    0xfaa4b(%rip),%rcx        # 0xfaa5b
  10:	f7 d8                	neg    %eax
  12:	64 89 01             	mov    %eax,%fs:(%rcx)
  15:	48                   	rex.W
[    9.606190][  T179] RSP: 002b:00007ffc11307a78 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[    9.606192][  T179] RAX: ffffffffffffffda RBX: 000055c0499bb700 RCX: 00007f30a983f37d
[    9.606194][  T179] RDX: 0000000000000000 RSI: 000055c019591ffd RDI: 0000000000000005
[    9.606194][  T179] RBP: 00007ffc11307b10 R08: 0000000000000000 R09: 0000000000000000
[    9.606195][  T179] R10: 0000000000000000 R11: 0000000000000246 R12: 000055c019591ffd
[    9.606196][  T179] R13: 000055c0499bb810 R14: 0000000000040000 R15: 0000000000000000
| [   13.435253][  T167] softirqs last disabled at (150172): restore_fpregs_from_user (./include/linux/bottom_half.h:20 (discriminator 2) ./arch/x86/include/asm/fpu/api.h:69 (discriminator 2) arch/x86/kernel/fpu/signal.c:277 (discriminator 2))
| [   13.435256][  T167] Preemption disabled at:
| [   13.435257][  T167] vprintk_emit (kernel/printk/printk.c:2471)
| [   13.435266][  T167] Tainted: [W]=WARN
[   13.435267][  T167] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.435269][  T167] Call Trace:
[   13.435270][  T167]  <TASK>
[   13.435272][  T167]  dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)
[   13.435276][  T167]  ? vprintk_emit (kernel/printk/printk.c:2471)
[   13.435278][  T167]  __might_resched.cold (kernel/sched/core.c:9234)
[   13.435283][  T167]  ? perf_trace_sched_switch (./include/linux/list.h:1037 (discriminator 3))
[   13.435286][  T167]  ? __kmalloc_noprof (./include/linux/sched/mm.h:317 mm/slub.c:4636 mm/slub.c:4974 mm/slub.c:5413 mm/slub.c:5439)
[   13.435292][  T167]  __kmalloc_noprof (./include/linux/sched/mm.h:322 (discriminator 2) mm/slub.c:4636 (discriminator 2) mm/slub.c:4974 (discriminator 2) mm/slub.c:5413 (discriminator 2) mm/slub.c:5439 (discriminator 2))
[   13.435294][  T167]  ? alloc_buf.isra.0 (./include/linux/slab.h:995 drivers/char/virtio_console.c:429)
[   13.435301][  T167]  ? do_raw_spin_unlock (./include/linux/instrumented.h:82 ./include/linux/atomic/atomic-instrumented.h:32 ./include/asm-generic/qspinlock.h:58 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141)
[   13.435303][  T167]  alloc_buf.isra.0 (./include/linux/slab.h:995 drivers/char/virtio_console.c:429)
[   13.435307][  T167]  put_chars (drivers/char/virtio_console.c:1176)
[   13.435310][  T167]  ? __send_to_port (drivers/char/virtio_console.c:654)
[   13.435312][  T167]  ? printk_get_next_message (kernel/printk/printk.c:3072)
[   13.435315][  T167]  ? rcu_read_lock_any_held (./include/linux/lockdep.h:249 kernel/rcu/update.c:386 kernel/rcu/update.c:380)
[   13.435318][  T167]  ? validate_chain (kernel/locking/lockdep.c:3817 (discriminator 2) kernel/locking/lockdep.c:3837 (discriminator 2) kernel/locking/lockdep.c:3892 (discriminator 2))
[   13.435323][  T167]  hvc_console_print (drivers/tty/hvc/hvc_console.c:177 (discriminator 2))
[   13.435327][  T167]  ? __lock_acquire (kernel/locking/lockdep.c:5254)
[   13.435329][  T167]  ? __lock_acquire (kernel/locking/lockdep.c:5254)
[   13.435334][  T167]  ? hvc_write (drivers/tty/hvc/hvc_console.c:501)
[   13.435337][  T167]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[   13.435340][  T167]  ? lock_acquire (./include/trace/events/lock.h:23 (discriminator 22) kernel/locking/lockdep.c:5871 (discriminator 22))
[   13.435344][  T167]  console_emit_next_record (kernel/printk/printk.c:3183)
[   13.435347][  T167]  ? devkmsg_read (./arch/x86/include/asm/atomic64_64.h:20)
[   13.435351][  T167]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[   13.435353][  T167]  ? lock_acquire (./include/trace/events/lock.h:23 (discriminator 22) kernel/locking/lockdep.c:5871 (discriminator 22))
[   13.435357][  T167]  console_flush_one_record (kernel/printk/printk.c:3268)
[   13.435361][  T167]  ? console_emit_next_record (kernel/printk/printk.c:3150)
[   13.435362][  T167]  ? __lock_acquire (kernel/locking/lockdep.c:5254)
[   13.435368][  T167]  console_unlock (kernel/printk/printk.c:3350 kernel/printk/printk.c:3380 kernel/printk/printk.c:3420)
[   13.435370][  T167]  ? console_flush_one_record (kernel/printk/printk.c:3316)
[   13.435371][  T167]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[   13.435373][  T167]  ? lock_acquire (kernel/locking/lockdep.c:5913)
[   13.435377][  T167]  ? __down_trylock_console_sem (kernel/printk/printk.c:334)
[   13.435379][  T167]  ? vprintk_emit (kernel/printk/printk.c:2478)
[   13.435382][  T167]  vprintk_emit (kernel/printk/printk.c:2479)
[   13.435385][  T167]  ? wake_up_klogd_work_func (kernel/printk/printk.c:4603 (discriminator 126))
[   13.435388][  T167]  ? _copy_from_iter (./include/linux/instrumented.h:146 lib/iov_iter.c:66 ./include/linux/iov_iter.h:30 ./include/linux/iov_iter.h:302 ./include/linux/iov_iter.h:330 lib/iov_iter.c:261 lib/iov_iter.c:272)
[   13.435393][  T167]  devkmsg_emit.constprop.0 (kernel/printk/printk.c:733)
[   13.435397][  T167]  ? vprintk_emit.cold (kernel/printk/printk.c:2449)
[   13.435401][  T167]  ? __kmalloc_noprof (mm/slub.c:5415 mm/slub.c:5439)
[   13.435403][  T167]  ? idr_get_free (??:?)
[   13.435407][  T167]  ? devkmsg_write (./include/linux/slab.h:995 kernel/printk/printk.c:762)
[   13.435409][  T167]  ? _copy_from_iter (./include/linux/instrumented.h:146 lib/iov_iter.c:66 ./include/linux/iov_iter.h:30 ./include/linux/iov_iter.h:302 ./include/linux/iov_iter.h:330 lib/iov_iter.c:261 lib/iov_iter.c:272)
[   13.435412][  T167]  devkmsg_write.cold (kernel/printk/printk.c:796)
[   13.435415][  T167]  ? vprintk_default (kernel/printk/printk.c:2494)
[   13.435416][  T167]  ? handle_pte_fault (mm/memory.c:6582)
[   13.435421][  T167]  ? do_numa_page.isra.0 (mm/memory.c:6319 (discriminator 1))
[   13.435423][  T167]  ? vprintk_default (kernel/printk/printk.c:2494)
[   13.435425][  T167]  new_sync_write (fs/read_write.c:595)
[   13.435429][  T167]  ? new_sync_read (./include/linux/ioprio.h:41)
[   13.435431][  T167]  ? lock_vma_under_rcu (./include/linux/rcupdate.h:319 (discriminator 2) ./include/linux/rcupdate.h:880 (discriminator 2) mm/mmap_lock.c:329 (discriminator 2))
[   13.435440][  T167]  vfs_write (fs/read_write.c:687)
[   13.435444][  T167]  ksys_write (fs/read_write.c:739)
[   13.435446][  T167]  ? __ia32_sys_read (fs/read_write.c:723)
[   13.435448][  T167]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[   13.435450][  T167]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 3) kernel/rcu/tree.c:753 (discriminator 3))
[   13.435458][  T167]  do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84)
[   13.435461][  T167]  ? exc_page_fault (arch/x86/mm/fault.c:1489 (discriminator 3) arch/x86/mm/fault.c:1536 (discriminator 3))
[   13.435464][  T167]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
[   13.435466][  T167] RIP: 0033:0x7f35fdda054e
[   13.435470][  T167] Code: 4d 89 d8 e8 b4 bd 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 <c9> c3 83 e2 39 83 fa 08 75 e7 e8 03 ff ff ff 0f 1f 00 f3 0f 1e fa
All code
========
   0:	4d 89 d8             	mov    %r11,%r8
   3:	e8 b4 bd 00 00       	call   0xbdbc
   8:	4c 8b 5d f8          	mov    -0x8(%rbp),%r11
   c:	41 8b 93 08 03 00 00 	mov    0x308(%r11),%edx
  13:	59                   	pop    %rcx
  14:	5e                   	pop    %rsi
  15:	48 83 f8 fc          	cmp    $0xfffffffffffffffc,%rax
  19:	74 11                	je     0x2c
  1b:	c9                   	leave
  1c:	c3                   	ret
  1d:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  24:	48 8b 45 10          	mov    0x10(%rbp),%rax
  28:	0f 05                	syscall
  2a:*	c9                   	leave		<-- trapping instruction
  2b:	c3                   	ret
  2c:	83 e2 39             	and    $0x39,%edx
  2f:	83 fa 08             	cmp    $0x8,%edx
  32:	75 e7                	jne    0x1b
  34:	e8 03 ff ff ff       	call   0xffffffffffffff3c
  39:	0f 1f 00             	nopl   (%rax)
  3c:	f3 0f 1e fa          	endbr64

Code starting with the faulting instruction
===========================================
   0:	c9                   	leave
   1:	c3                   	ret
   2:	83 e2 39             	and    $0x39,%edx
   5:	83 fa 08             	cmp    $0x8,%edx
   8:	75 e7                	jne    0xfffffffffffffff1
   a:	e8 03 ff ff ff       	call   0xffffffffffffff12
   f:	0f 1f 00             	nopl   (%rax)
  12:	f3 0f 1e fa          	endbr64
[   13.435472][  T167] RSP: 002b:00007ffd798025e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
[   13.435475][  T167] RAX: ffffffffffffffda RBX: 00007f35fdf21580 RCX: 00007f35fdda054e
[   13.435476][  T167] RDX: 0000000000000023 RSI: 00005627ce07f120 RDI: 0000000000000001
[   13.435477][  T167] RBP: 00007ffd798025f0 R08: 0000000000000000 R09: 0000000000000000
[   13.435478][  T167] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000023


Finger prints:
restore_fpregs_from_user:vprintk_emit:dump_stack_lvl:__kmalloc_noprof:put_chars
__irq_exit_rcu:vprintk_emit:dump_stack_lvl:__kmalloc_noprof:put_chars