==================================================================
BUG: KASAN: use-after-free in hlist_move_list include/linux/list.h:1014 [inline]
BUG: KASAN: use-after-free in collect_expired_timers kernel/time/timer.c:1576 [inline]
BUG: KASAN: use-after-free in __run_timers+0x34a/0xa10 kernel/time/timer.c:1812
Write of size 8 at addr ffff888117b44a00 by task udevd/102
CPU: 1 PID: 102 Comm: udevd Not tainted 6.1.118-syzkaller-00074-g3e3f2b9e9fca #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:316 [inline]
print_report+0x158/0x4e0 mm/kasan/report.c:427
kasan_report+0x13c/0x170 mm/kasan/report.c:531
__asan_report_store8_noabort+0x17/0x20 mm/kasan/report_generic.c:356
hlist_move_list include/linux/list.h:1014 [inline]
collect_expired_timers kernel/time/timer.c:1576 [inline]
__run_timers+0x34a/0xa10 kernel/time/timer.c:1812
run_timer_softirq+0x69/0xf0 kernel/time/timer.c:1839
handle_softirqs+0x1db/0x650 kernel/softirq.c:617
__do_softirq kernel/softirq.c:655 [inline]
invoke_softirq kernel/softirq.c:472 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:704
irq_exit_rcu+0x9/0x10 kernel/softirq.c:716
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:exit_to_user_mode_loop+0x47/0xa0 kernel/entry/common.c:164
Code: 0c 00 00 e8 6b 56 5d 00 e8 86 1e 03 01 fa e8 80 cc b7 03 65 48 8b 05 b8 a6 9e 7e 48 8b 18 f7 c3 0e 30 02 00 74 53 fb f6 c3 08 <74> 05 e8 f2 57 bc 03 f7 c3 00 10 00 00 74 08 4c 89 f7 e8 02 dd 3c
RSP: 0000:ffffc90000a17ec8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: 0000000000010000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffc90000a17f58
RBP: ffffc90000a17ed8 R08: dffffc0000000000 R09: ffffed1022076799
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90000a17f58 R15: ffff8881103b3cc0
exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:210
irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:316
irqentry_exit+0x12/0x40 kernel/entry/common.c:419
sysvec_reschedule_ipi+0x8f/0x170 arch/x86/kernel/smp.c:244
asm_sysvec_reschedule_ipi+0x1b/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0033:0x7f8d09c898f8
Code: 00 48 8b 05 92 76 16 00 31 c9 64 4c 8b 00 e9 22 00 00 00 48 8b 05 80 76 16 00 64 4c 8b 00 e9 44 03 00 00 48 8b 05 70 76 16 00 <31> c9 64 4c 8b 00 e9 32 03 00 00 41 57 41 89 ca 41 56 41 55 49 89
RSP: 002b:00007fff4d621fb8 EFLAGS: 00000246
RAX: fffffffffffffe50 RBX: 000055bc9e3621a0 RCX: 0000000000000006
RDX: 000000000000000a RSI: 0000000000000000 RDI: 00007fff4d6223ce
RBP: 00007fff4d6223c8 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 000055bc9e358b00
R13: 0000000000000000 R14: 0000000000000000 R15: 000055bc7e5fcfc1
Allocated by task 11217:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:379 [inline]
__kasan_kmalloc+0x9c/0xb0 mm/kasan/common.c:388
kasan_kmalloc include/linux/kasan.h:212 [inline]
__do_kmalloc_node mm/slab_common.c:938 [inline]
__kmalloc+0xb4/0x1e0 mm/slab_common.c:951
kmalloc include/linux/slab.h:562 [inline]
kzalloc include/linux/slab.h:693 [inline]
hci_alloc_dev_priv+0x27/0x1c00 net/bluetooth/hci_core.c:2435
hci_alloc_dev include/net/bluetooth/hci_core.h:1484 [inline]
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:636 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:712 [inline]
hci_uart_tty_ioctl+0x401/0xa70 drivers/bluetooth/hci_ldisc.c:765
tty_ioctl+0x903/0xc50 drivers/tty/tty_io.c:2785
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0x114/0x190 fs/ioctl.c:856
__x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 11217:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0x131/0x180 mm/kasan/common.c:241
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:249
kasan_slab_free include/linux/kasan.h:178 [inline]
slab_free_hook mm/slub.c:1745 [inline]
slab_free_freelist_hook mm/slub.c:1771 [inline]
slab_free mm/slub.c:3686 [inline]
__kmem_cache_free+0x21d/0x410 mm/slub.c:3702
kfree+0x7a/0xf0 mm/slab_common.c:990
hci_release_dev+0x14d3/0x1640 net/bluetooth/hci_core.c:2763
bt_host_release+0x83/0xa0 net/bluetooth/hci_sysfs.c:92
device_release+0x95/0x1c0
kobject_cleanup lib/kobject.c:681 [inline]
kobject_release lib/kobject.c:712 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x178/0x260 lib/kobject.c:729
put_device+0x1f/0x30 drivers/base/core.c:3805
hci_dev_put include/net/bluetooth/hci_core.h:1444 [inline]
hci_dev_cmd+0x2be/0x9b0 net/bluetooth/hci_core.c:795
hci_sock_ioctl+0x415/0x7f0 net/bluetooth/hci_sock.c:1096
sock_do_ioctl+0x152/0x450 net/socket.c:1194
sock_ioctl+0x455/0x740 net/socket.c:1311
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0x114/0x190 fs/ioctl.c:856
__x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Last potentially related work creation:
kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45
__kasan_record_aux_stack+0xb4/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
insert_work+0x56/0x310 kernel/workqueue.c:1368
__queue_work+0x9b6/0xd70 kernel/workqueue.c:1527
queue_work_on+0x105/0x170 kernel/workqueue.c:1555
queue_work include/linux/workqueue.h:510 [inline]
hci_cmd_sync_run net/bluetooth/hci_sync.c:140 [inline]
__hci_cmd_sync_sk+0xc2a/0xf70 net/bluetooth/hci_sync.c:162
__hci_cmd_sync_status_sk net/bluetooth/hci_sync.c:253 [inline]
__hci_cmd_sync_status net/bluetooth/hci_sync.c:277 [inline]
hci_cmd_sync_status+0x52/0x130 net/bluetooth/hci_sync.c:288
hci_dev_cmd+0x39e/0x9b0 net/bluetooth/hci_core.c:749
hci_sock_ioctl+0x415/0x7f0 net/bluetooth/hci_sock.c:1096
sock_do_ioctl+0x152/0x450 net/socket.c:1194
sock_ioctl+0x455/0x740 net/socket.c:1311
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0x114/0x190 fs/ioctl.c:856
__x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
x64_sys_call+0x98/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Second to last potentially related work creation:
kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45
__kasan_record_aux_stack+0xb4/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
insert_work+0x56/0x310 kernel/workqueue.c:1368
__queue_work+0x9b6/0xd70 kernel/workqueue.c:1527
queue_work_on+0x105/0x170 kernel/workqueue.c:1555
queue_work include/linux/workqueue.h:510 [inline]
hci_cmd_timeout+0x199/0x200 net/bluetooth/hci_core.c:1468
process_one_work+0x73d/0xcb0 kernel/workqueue.c:2299
worker_thread+0xa60/0x1260 kernel/workqueue.c:2446
kthread+0x26d/0x300 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
The buggy address belongs to the object at ffff888117b44000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2560 bytes inside of
8192-byte region [ffff888117b44000, ffff888117b46000)
The buggy address belongs to the physical page:
page:ffffea00045ed000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117b40
head:ffffea00045ed000 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 0000000000000000 dead000000000001 ffff888100043500
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 10929, tgid 10915 (syz.7.3163), ts 751887892321, free_ts 738813576723
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x213/0x220 mm/page_alloc.c:2590
prep_new_page+0x1b/0x110 mm/page_alloc.c:2597
get_page_from_freelist+0x2f41/0x2fc0 mm/page_alloc.c:4462
__alloc_pages+0x234/0x610 mm/page_alloc.c:5759
alloc_slab_page+0x6c/0xf0
allocate_slab mm/slub.c:1962 [inline]
new_slab+0x90/0x3e0 mm/slub.c:2015
___slab_alloc+0x6f9/0xb80 mm/slub.c:3203
__slab_alloc+0x5d/0xa0 mm/slub.c:3302
slab_alloc_node mm/slub.c:3387 [inline]
__kmem_cache_alloc_node+0x207/0x2a0 mm/slub.c:3462
__do_kmalloc_node mm/slab_common.c:937 [inline]
__kmalloc_node+0xa3/0x1e0 mm/slab_common.c:945
kmalloc_node include/linux/slab.h:583 [inline]
kvmalloc_node+0x221/0x640 mm/util.c:592
kvmalloc include/linux/slab.h:710 [inline]
kvmalloc_array include/linux/slab.h:728 [inline]
__ptr_ring_init_queue_alloc include/linux/ptr_ring.h:471 [inline]
ptr_ring_init include/linux/ptr_ring.h:489 [inline]
skb_array_init include/linux/skb_array.h:182 [inline]
pfifo_fast_init+0x25e/0x7a0 net/sched/sch_generic.c:867
qdisc_create_dflt+0x144/0x3e0 net/sched/sch_generic.c:1013
mq_init+0x2c8/0x6b0 net/sched/sch_mq.c:90
qdisc_create_dflt+0x144/0x3e0 net/sched/sch_generic.c:1013
attach_default_qdiscs net/sched/sch_generic.c:1192 [inline]
dev_activate+0x159/0x1130 net/sched/sch_generic.c:1246
page last free stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
free_pages_prepare mm/page_alloc.c:1498 [inline]
free_pcp_prepare mm/page_alloc.c:1572 [inline]
free_unref_page_prepare+0x83d/0x850 mm/page_alloc.c:3511
free_unref_page+0xb2/0x5c0 mm/page_alloc.c:3607
free_the_page mm/page_alloc.c:798 [inline]
__free_pages+0x61/0xf0 mm/page_alloc.c:5848
__free_slab+0xce/0x1a0 mm/slub.c:2039
free_slab mm/slub.c:2054 [inline]
discard_slab mm/slub.c:2060 [inline]
__unfreeze_partials+0x165/0x1a0 mm/slub.c:2609
put_cpu_partial+0xa9/0x100 mm/slub.c:2685
__slab_free+0x1c8/0x280 mm/slub.c:3563
do_slab_free mm/slub.c:3640 [inline]
___cache_free+0xc6/0xd0 mm/slub.c:3696
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0xc5/0x140 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x15a/0x180 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:310
kasan_slab_alloc include/linux/kasan.h:202 [inline]
slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:768
slab_alloc_node mm/slub.c:3421 [inline]
kmem_cache_alloc_node+0x188/0x330 mm/slub.c:3468
__alloc_skb+0xcc/0x2d0 net/core/skbuff.c:505
alloc_skb include/linux/skbuff.h:1290 [inline]
nlmsg_new include/net/netlink.h:991 [inline]
inet_netconf_notify_devconf+0x173/0x230 net/ipv4/devinet.c:2128
__devinet_sysctl_unregister net/ipv4/devinet.c:2639 [inline]
devinet_sysctl_unregister net/ipv4/devinet.c:2663 [inline]
inetdev_destroy net/ipv4/devinet.c:329 [inline]
inetdev_event+0x823/0x1110 net/ipv4/devinet.c:1615
Memory state around the buggy address:
ffff888117b44900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888117b44980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888117b44a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888117b44a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888117b44b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 102 Comm: udevd Tainted: G B 6.1.118-syzkaller-00074-g3e3f2b9e9fca #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
RIP: 0010:__queue_work+0x4f1/0xd70
Code: 39 03 0f 84 40 01 00 00 e8 fc 6b 2a 00 4c 89 e7 e8 e4 d3 d6 03 49 bd 00 00 00 00 00 fc ff df 4c 8b 65 d0 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 f7 e8 30 df 71 00 49 8b 3e e8 98 cc d6
RSP: 0000:ffffc900001b0c78 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 000000007fffffff RCX: ffff8881103b3cc0
RDX: 0000000000000100 RSI: 000000007fffffff RDI: 000000007fffffff
RBP: ffffc900001b0d00 R08: ffffffff814b186b R09: 0000000000000007
R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff888117b449c8
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888117b449e0
FS: 00007f8d0a093c80(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffdfa50000 CR3: 00000001107df000 CR4: 00000000003506a0
Call Trace:
delayed_work_timer_fn+0x61/0x80 kernel/workqueue.c:1653
call_timer_fn+0x3b/0x2d0 kernel/time/timer.c:1510
expire_timers kernel/time/timer.c:1550 [inline]
__run_timers+0x756/0xa10 kernel/time/timer.c:1826
run_timer_softirq+0x69/0xf0 kernel/time/timer.c:1839
handle_softirqs+0x1db/0x650 kernel/softirq.c:617
__do_softirq kernel/softirq.c:655 [inline]
invoke_softirq kernel/softirq.c:472 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:704
irq_exit_rcu+0x9/0x10 kernel/softirq.c:716
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:exit_to_user_mode_loop+0x47/0xa0 kernel/entry/common.c:164
Code: 0c 00 00 e8 6b 56 5d 00 e8 86 1e 03 01 fa e8 80 cc b7 03 65 48 8b 05 b8 a6 9e 7e 48 8b 18 f7 c3 0e 30 02 00 74 53 fb f6 c3 08 <74> 05 e8 f2 57 bc 03 f7 c3 00 10 00 00 74 08 4c 89 f7 e8 02 dd 3c
RSP: 0000:ffffc90000a17ec8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: 0000000000010000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffc90000a17f58
RBP: ffffc90000a17ed8 R08: dffffc0000000000 R09: ffffed1022076799
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90000a17f58 R15: ffff8881103b3cc0
exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:210
irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:316
irqentry_exit+0x12/0x40 kernel/entry/common.c:419
sysvec_reschedule_ipi+0x8f/0x170 arch/x86/kernel/smp.c:244
asm_sysvec_reschedule_ipi+0x1b/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0033:0x7f8d09c898f8
Code: 00 48 8b 05 92 76 16 00 31 c9 64 4c 8b 00 e9 22 00 00 00 48 8b 05 80 76 16 00 64 4c 8b 00 e9 44 03 00 00 48 8b 05 70 76 16 00 <31> c9 64 4c 8b 00 e9 32 03 00 00 41 57 41 89 ca 41 56 41 55 49 89
RSP: 002b:00007fff4d621fb8 EFLAGS: 00000246
RAX: fffffffffffffe50 RBX: 000055bc9e3621a0 RCX: 0000000000000006
RDX: 000000000000000a RSI: 0000000000000000 RDI: 00007fff4d6223ce
RBP: 00007fff4d6223c8 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 000055bc9e358b00
R13: 0000000000000000 R14: 0000000000000000 R15: 000055bc7e5fcfc1
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__queue_work+0x4f1/0xd70
Code: 39 03 0f 84 40 01 00 00 e8 fc 6b 2a 00 4c 89 e7 e8 e4 d3 d6 03 49 bd 00 00 00 00 00 fc ff df 4c 8b 65 d0 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 f7 e8 30 df 71 00 49 8b 3e e8 98 cc d6
RSP: 0000:ffffc900001b0c78 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 000000007fffffff RCX: ffff8881103b3cc0
RDX: 0000000000000100 RSI: 000000007fffffff RDI: 000000007fffffff
RBP: ffffc900001b0d00 R08: ffffffff814b186b R09: 0000000000000007
R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff888117b449c8
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888117b449e0
FS: 00007f8d0a093c80(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffdfa50000 CR3: 00000001107df000 CR4: 00000000003506a0
----------------
Code disassembly (best guess):
0: 0c 00 or $0x0,%al
2: 00 e8 add %ch,%al
4: 6b 56 5d 00 imul $0x0,0x5d(%rsi),%edx
8: e8 86 1e 03 01 call 0x1031e93
d: fa cli
e: e8 80 cc b7 03 call 0x3b7cc93
13: 65 48 8b 05 b8 a6 9e mov %gs:0x7e9ea6b8(%rip),%rax # 0x7e9ea6d3
1a: 7e
1b: 48 8b 18 mov (%rax),%rbx
1e: f7 c3 0e 30 02 00 test $0x2300e,%ebx
24: 74 53 je 0x79
26: fb sti
27: f6 c3 08 test $0x8,%bl
* 2a: 74 05 je 0x31 <-- trapping instruction
2c: e8 f2 57 bc 03 call 0x3bc5823
31: f7 c3 00 10 00 00 test $0x1000,%ebx
37: 74 08 je 0x41
39: 4c 89 f7 mov %r14,%rdi
3c: e8 .byte 0xe8
3d: 02 dd add %ch,%bl
3f: 3c .byte 0x3c