kobject: kobject_add_internal failed for hci0:201 with -EEXIST, don't try to register things with the same name in the same directory.
Bluetooth: hci0: failed to register connection device
==================================================================
BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1484
Read of size 8 at addr ffff8880699d7580 by task kworker/u9:0/20387

CPU: 1 UID: 0 PID: 20387 Comm: kworker/u9:0 Not tainted 6.14.0-rc3-syzkaller-00060-g6537cfb395f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:489
 kasan_report+0xd9/0x110 mm/kasan/report.c:602
 l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1484
 l2cap_connect_cfm+0x862/0xf10 net/bluetooth/l2cap_core.c:7223
 hci_connect_cfm include/net/bluetooth/hci_core.h:2051 [inline]
 le_conn_complete_evt+0x1690/0x1da0 net/bluetooth/hci_event.c:5763
 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5789
 hci_le_meta_evt+0x2e5/0x5d0 net/bluetooth/hci_event.c:7162
 hci_event_func net/bluetooth/hci_event.c:7470 [inline]
 hci_event_packet+0x669/0x1180 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4015
 process_one_work+0x9c8/0x1ba0 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 kthread+0x3b2/0x750 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 20387:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4294 [inline]
 __kmalloc_noprof+0x21c/0x510 mm/slub.c:4306
 kmalloc_noprof include/linux/slab.h:905 [inline]
 sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2181
 sk_alloc+0x36/0xb90 net/core/sock.c:2234
 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:148
 l2cap_sock_alloc.constprop.0+0x33/0x1d0 net/bluetooth/l2cap_sock.c:1878
 l2cap_sock_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1469
 l2cap_connect_cfm+0x862/0xf10 net/bluetooth/l2cap_core.c:7223
 hci_connect_cfm include/net/bluetooth/hci_core.h:2051 [inline]
 le_conn_complete_evt+0x1690/0x1da0 net/bluetooth/hci_event.c:5763
 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5789
 hci_le_meta_evt+0x2e5/0x5d0 net/bluetooth/hci_event.c:7162
 hci_event_func net/bluetooth/hci_event.c:7470 [inline]
 hci_event_packet+0x669/0x1180 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4015
 process_one_work+0x9c8/0x1ba0 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 kthread+0x3b2/0x750 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Freed by task 22514:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4609 [inline]
 kfree+0x2c4/0x4d0 mm/slub.c:4757
 sk_prot_free net/core/sock.c:2217 [inline]
 __sk_destruct+0x5eb/0x720 net/core/sock.c:2309
 sk_destruct+0xc2/0xf0 net/core/sock.c:2324
 __sk_free+0xf4/0x3e0 net/core/sock.c:2335
 sk_free+0x6a/0x90 net/core/sock.c:2346
 sock_put include/net/sock.h:1913 [inline]
 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1252 [inline]
 l2cap_sock_kill+0x171/0x2d0 net/bluetooth/l2cap_sock.c:1237
 l2cap_sock_cleanup_listen+0x3d/0x2a0 net/bluetooth/l2cap_sock.c:1449
 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1412
 __sock_release+0xb3/0x270 net/socket.c:647
 sock_close+0x1c/0x30 net/socket.c:1398
 __fput+0x402/0xb70 fs/file_table.c:464
 task_work_run+0x151/0x250 kernel/task_work.c:227
 get_signal+0x1d3/0x26c0 kernel/signal.c:2809
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880699d7000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1408 bytes inside of
 freed 2048-byte region [ffff8880699d7000, ffff8880699d7800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x699d0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b042000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b042000 dead000000000122 0000000000000000
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001a67401 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5195, tgid 5195 (klogd), ts 1983796030348, free_ts 1983383713500
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x221/0x2470 mm/page_alloc.c:4739
 alloc_pages_mpol+0x1fc/0x540 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab mm/slub.c:2587 [inline]
 new_slab+0x23d/0x330 mm/slub.c:2640
 ___slab_alloc+0xc5d/0x1720 mm/slub.c:3826
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 __kmalloc_cache_noprof+0xfa/0x410 mm/slub.c:4320
 kmalloc_noprof include/linux/slab.h:901 [inline]
 syslog_print+0xf9/0x5d0 kernel/printk/printk.c:1607
 do_syslog+0x3e1/0x6c0 kernel/printk/printk.c:1785
 __do_sys_syslog kernel/printk/printk.c:1877 [inline]
 __se_sys_syslog kernel/printk/printk.c:1875 [inline]
 __x64_sys_syslog+0x74/0xb0 kernel/printk/printk.c:1875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 22511 tgid 22510 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0x6db/0xfb0 mm/page_alloc.c:2660
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 __do_kmalloc_node mm/slub.c:4293 [inline]
 __kmalloc_node_track_caller_noprof+0x1d3/0x510 mm/slub.c:4313
 memdup_user+0x2a/0xd0 mm/util.c:218
 strndup_user+0x78/0xe0 mm/util.c:277
 copy_mount_string fs/namespace.c:3795 [inline]
 __do_sys_mount fs/namespace.c:4096 [inline]
 __se_sys_mount fs/namespace.c:4088 [inline]
 __x64_sys_mount+0x138/0x310 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880699d7480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880699d7500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880699d7580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880699d7600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880699d7680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in l2cap_connect_cfm+0x884/0xf10 net/bluetooth/l2cap_core.c:7225
Write of size 6 at addr ffff88807c9b1018 by task kworker/u9:0/20387

CPU: 1 UID: 0 PID: 20387 Comm: kworker/u9:0 Tainted: G    B              6.14.0-rc3-syzkaller-00060-g6537cfb395f3 #0
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:489
 kasan_report+0xd9/0x110 mm/kasan/report.c:602
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 __asan_memcpy+0x3c/0x60 mm/kasan/shadow.c:106
 l2cap_connect_cfm+0x884/0xf10 net/bluetooth/l2cap_core.c:7225
 hci_connect_cfm include/net/bluetooth/hci_core.h:2051 [inline]
 le_conn_complete_evt+0x1690/0x1da0 net/bluetooth/hci_event.c:5763
 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5789
 hci_le_meta_evt+0x2e5/0x5d0 net/bluetooth/hci_event.c:7162
 hci_event_func net/bluetooth/hci_event.c:7470 [inline]
 hci_event_packet+0x669/0x1180 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4015
 process_one_work+0x9c8/0x1ba0 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 kthread+0x3b2/0x750 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 20387:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 l2cap_chan_create+0x44/0x920 net/bluetooth/l2cap_core.c:445
 l2cap_sock_alloc.constprop.0+0xf5/0x1d0 net/bluetooth/l2cap_sock.c:1887
 l2cap_sock_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1469
 l2cap_connect_cfm+0x862/0xf10 net/bluetooth/l2cap_core.c:7223
 hci_connect_cfm include/net/bluetooth/hci_core.h:2051 [inline]
 le_conn_complete_evt+0x1690/0x1da0 net/bluetooth/hci_event.c:5763
 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5789
 hci_le_meta_evt+0x2e5/0x5d0 net/bluetooth/hci_event.c:7162
 hci_event_func net/bluetooth/hci_event.c:7470 [inline]
 hci_event_packet+0x669/0x1180 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4015
 process_one_work+0x9c8/0x1ba0 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 kthread+0x3b2/0x750 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Freed by task 22514:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4609 [inline]
 kfree+0x2c4/0x4d0 mm/slub.c:4757
 l2cap_chan_destroy net/bluetooth/l2cap_core.c:491 [inline]
 kref_put include/linux/kref.h:65 [inline]
 l2cap_chan_put+0x216/0x2c0 net/bluetooth/l2cap_core.c:515
 l2cap_sock_cleanup_listen+0x4d/0x2a0 net/bluetooth/l2cap_sock.c:1452
 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1412
 __sock_release+0xb3/0x270 net/socket.c:647
 sock_close+0x1c/0x30 net/socket.c:1398
 __fput+0x402/0xb70 fs/file_table.c:464
 task_work_run+0x151/0x250 kernel/task_work.c:227
 get_signal+0x1d3/0x26c0 kernel/signal.c:2809
 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807c9b1000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 24 bytes inside of
 freed 2048-byte region [ffff88807c9b1000, ffff88807c9b1800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7c9b0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b042000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b042000 dead000000000100 dead000000000122
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001f26c01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5835, tgid 5835 (syz-executor), ts 92663139352, free_ts 92656344849
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x221/0x2470 mm/page_alloc.c:4739
 alloc_pages_mpol+0x1fc/0x540 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab mm/slub.c:2587 [inline]
 new_slab+0x23d/0x330 mm/slub.c:2640
 ___slab_alloc+0xc5d/0x1720 mm/slub.c:3826
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 __do_kmalloc_node mm/slub.c:4293 [inline]
 __kmalloc_node_track_caller_noprof+0x2f1/0x510 mm/slub.c:4313
 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:609
 pskb_expand_head+0x243/0x1240 net/core/skbuff.c:2275
 netlink_trim+0x22d/0x310 net/netlink/af_netlink.c:1304
 netlink_broadcast_filtered+0xc7/0xef0 net/netlink/af_netlink.c:1510
 nlmsg_multicast_filtered include/net/netlink.h:1128 [inline]
 nlmsg_multicast include/net/netlink.h:1147 [inline]
 nlmsg_notify+0x9e/0x220 net/netlink/af_netlink.c:2586
 rtnl_notify net/core/rtnetlink.c:952 [inline]
 rtmsg_ifinfo_send net/core/rtnetlink.c:4386 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4402 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4389 [inline]
 rtmsg_ifinfo+0x174/0x1a0 net/core/rtnetlink.c:4408
 __dev_notify_flags+0x24e/0x2e0 net/core/dev.c:9207
 rtnl_configure_link+0x1b7/0x260 net/core/rtnetlink.c:3562
page last free pid 5835 tgid 5835 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0x6db/0xfb0 mm/page_alloc.c:2660
 __put_partials+0x14c/0x170 mm/slub.c:3153
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x226/0x3d0 mm/slub.c:4171
 __kernfs_new_node+0xd3/0x890 fs/kernfs/dir.c:624
 kernfs_new_node+0x186/0x240 fs/kernfs/dir.c:700
 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1034
 sysfs_add_file_mode_ns+0x1ff/0x3b0 fs/sysfs/file.c:313
 create_files fs/sysfs/group.c:76 [inline]
 internal_create_group+0x56c/0xf10 fs/sysfs/group.c:183
 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:223
 device_add_groups drivers/base/core.c:2812 [inline]
 device_add_attrs drivers/base/core.c:2887 [inline]
 device_add+0xf33/0x1a70 drivers/base/core.c:3619
 netdev_register_kobject+0x183/0x3a0 net/core/net-sysfs.c:2170
 register_netdevice+0x147b/0x1eb0 net/core/dev.c:10861
 veth_newlink+0x291/0x8f0 drivers/net/veth.c:1815

Memory state around the buggy address:
 ffff88807c9b0f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88807c9b0f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807c9b1000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88807c9b1080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807c9b1100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================