==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:147 [inline]
BUG: KASAN: use-after-free in skb_unref include/linux/skbuff.h:1131 [inline]
BUG: KASAN: use-after-free in consume_skb+0x3c/0x250 net/core/skbuff.c:926
Read of size 4 at addr ffff8881263ff4ac by task syz.4.3013/9116

CPU: 0 PID: 9116 Comm: syz.4.3013 Tainted: G        W         5.15.161-syzkaller-00425-gb92c0d35d015 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1c0 lib/dump_stack.c:106
 print_address_description+0x87/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:444
 kasan_check_range+0x293/0x2a0 mm/kasan/generic.c:189
 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 refcount_read include/linux/refcount.h:147 [inline]
 skb_unref include/linux/skbuff.h:1131 [inline]
 consume_skb+0x3c/0x250 net/core/skbuff.c:926
 __sk_msg_free+0x2dd/0x370 net/core/skmsg.c:205
 sk_msg_free net/core/skmsg.c:218 [inline]
 __sk_psock_purge_ingress_msg net/core/skmsg.c:768 [inline]
 __sk_psock_zap_ingress net/core/skmsg.c:786 [inline]
 sk_psock_stop+0x44c/0x4d0 net/core/skmsg.c:804
 sock_map_close+0x2b9/0x4c0 net/core/sock_map.c:1554
 unix_release+0x82/0xc0 net/unix/af_unix.c:949
 __sock_release net/socket.c:649 [inline]
 sock_close+0xdf/0x270 net/socket.c:1336
 __fput+0x3fe/0x910 fs/file_table.c:280
 ____fput+0x15/0x20 fs/file_table.c:308
 task_work_run+0x129/0x190 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0xc4/0xe0 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x26/0x160 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff26a1a4ef9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd6b36b9c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000067e68 RCX: 00007ff26a1a4ef9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ff26a35ea80 R08: 0000000000000001 R09: 00007ffd6b36bcbf
R10: 00007ff26a027000 R11: 0000000000000246 R12: 0000000000067ece
R13: 00007ffd6b36bad0 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>

Allocated by task 9119:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:433 [inline]
 __kasan_slab_alloc+0xb1/0xe0 mm/kasan/common.c:466
 kasan_slab_alloc include/linux/kasan.h:217 [inline]
 slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:550
 slab_alloc_node mm/slub.c:3240 [inline]
 slab_alloc mm/slub.c:3248 [inline]
 kmem_cache_alloc+0xf5/0x200 mm/slub.c:3253
 skb_clone+0x1d1/0x360 net/core/skbuff.c:1547
 sk_psock_verdict_recv+0x53/0x840 net/core/skmsg.c:1182
 unix_read_sock+0x132/0x370 net/unix/af_unix.c:2433
 sk_psock_verdict_data_ready+0x147/0x1a0 net/core/skmsg.c:1225
 unix_dgram_sendmsg+0x15fa/0x2090 net/unix/af_unix.c:1947
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431
 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485
 __sys_sendmsg net/socket.c:2514 [inline]
 __do_sys_sendmsg net/socket.c:2523 [inline]
 __se_sys_sendmsg+0x19a/0x260 net/socket.c:2521
 __x64_sys_sendmsg+0x7b/0x90 net/socket.c:2521
 x64_sys_call+0x16a/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 337:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x126/0x160 mm/kasan/common.c:365
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1723 [inline]
 slab_free_freelist_hook+0xbd/0x190 mm/slub.c:1749
 slab_free mm/slub.c:3519 [inline]
 kmem_cache_free+0x116/0x2e0 mm/slub.c:3535
 kfree_skbmem+0x104/0x170
 __kfree_skb net/core/skbuff.c:758 [inline]
 kfree_skb_reason net/core/skbuff.c:778 [inline]
 kfree_skb+0xc2/0x360 net/core/skbuff.c:792
 sock_drop include/linux/skmsg.h:312 [inline]
 sk_psock_backlog+0xc21/0xd90 net/core/skmsg.c:681
 process_one_work+0x6bb/0xc10 kernel/workqueue.c:2325
 worker_thread+0xad5/0x12a0 kernel/workqueue.c:2472
 kthread+0x421/0x510 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300

The buggy address belongs to the object at ffff8881263ff3c0
 which belongs to the cache skbuff_head_cache of size 248
The buggy address is located 236 bytes inside of
 248-byte region [ffff8881263ff3c0, ffff8881263ff4b8)
The buggy address belongs to the page:
page:ffffea000498ffc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1263ff
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea0004f3f900 0000000600000006 ffff8881081b3980
raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 7493, ts 357553264999, free_ts 356684031633
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1a3/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x3550/0x35d0 mm/page_alloc.c:4485
 __alloc_pages+0x27e/0x8f0 mm/page_alloc.c:5779
 allocate_slab mm/slub.c:1932 [inline]
 new_slab+0x9a/0x4e0 mm/slub.c:1995
 ___slab_alloc+0x39e/0x830 mm/slub.c:3028
 __slab_alloc+0x4a/0x90 mm/slub.c:3115
 slab_alloc_node mm/slub.c:3206 [inline]
 slab_alloc mm/slub.c:3248 [inline]
 kmem_cache_alloc+0x134/0x200 mm/slub.c:3253
 skb_clone+0x1d1/0x360 net/core/skbuff.c:1547
 ____bpf_clone_redirect net/core/filter.c:2424 [inline]
 bpf_clone_redirect+0xa6/0x390 net/core/filter.c:2411
 bpf_prog_d241a00e15f251e5+0x512/0x98c
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x478/0xa10 net/bpf/test_run.c:119
 bpf_prog_test_run_skb+0xb41/0x1420 net/bpf/test_run.c:663
 bpf_prog_test_run+0x3b0/0x630 kernel/bpf/syscall.c:3348
 __sys_bpf+0x525/0x760 kernel/bpf/syscall.c:4651
 __do_sys_bpf kernel/bpf/syscall.c:4737 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4735 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:4735
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x7c8/0x7d0 mm/page_alloc.c:3534
 free_unref_page_list+0x14b/0xa60 mm/page_alloc.c:3671
 release_pages+0x1310/0x1370 mm/swap.c:1009
 free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:320
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:338
 exit_mmap+0x40d/0x940 mm/mmap.c:3218
 __mmput+0x95/0x310 kernel/fork.c:1179
 mmput+0x5b/0x170 kernel/fork.c:1202
 exit_mm kernel/exit.c:552 [inline]
 do_exit+0xb9c/0x2ca0 kernel/exit.c:865
 __do_sys_exit kernel/exit.c:969 [inline]
 __se_sys_exit kernel/exit.c:967 [inline]
 __ia32_sys_exit+0x0/0x40 kernel/exit.c:967
 x64_sys_call+0x1cc/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:61
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff8881263ff380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
 ffff8881263ff400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881263ff480: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
                                  ^
 ffff8881263ff500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881263ff580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
==================================================================
==================================================================
BUG: KASAN: double-free or invalid-free in slab_free mm/slub.c:3519 [inline]
BUG: KASAN: double-free or invalid-free in kmem_cache_free+0x116/0x2e0 mm/slub.c:3535

CPU: 0 PID: 9116 Comm: syz.4.3013 Tainted: G    B   W         5.15.161-syzkaller-00425-gb92c0d35d015 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1c0 lib/dump_stack.c:106
 print_address_description+0x87/0x3b0 mm/kasan/report.c:248
 kasan_report_invalid_free+0x6b/0xa0 mm/kasan/report.c:370
 ____kasan_slab_free+0x13e/0x160
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1723 [inline]
 slab_free_freelist_hook+0xbd/0x190 mm/slub.c:1749
 slab_free mm/slub.c:3519 [inline]
 kmem_cache_free+0x116/0x2e0 mm/slub.c:3535
 kfree_skbmem+0x104/0x170
 __kfree_skb net/core/skbuff.c:758 [inline]
 consume_skb+0xb4/0x250 net/core/skbuff.c:930
 __sk_msg_free+0x2dd/0x370 net/core/skmsg.c:205
 sk_msg_free net/core/skmsg.c:218 [inline]
 __sk_psock_purge_ingress_msg net/core/skmsg.c:768 [inline]
 __sk_psock_zap_ingress net/core/skmsg.c:786 [inline]
 sk_psock_stop+0x44c/0x4d0 net/core/skmsg.c:804
 sock_map_close+0x2b9/0x4c0 net/core/sock_map.c:1554
 unix_release+0x82/0xc0 net/unix/af_unix.c:949
 __sock_release net/socket.c:649 [inline]
 sock_close+0xdf/0x270 net/socket.c:1336
 __fput+0x3fe/0x910 fs/file_table.c:280
 ____fput+0x15/0x20 fs/file_table.c:308
 task_work_run+0x129/0x190 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0xc4/0xe0 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x26/0x160 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff26a1a4ef9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd6b36b9c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000067e68 RCX: 00007ff26a1a4ef9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ff26a35ea80 R08: 0000000000000001 R09: 00007ffd6b36bcbf
R10: 00007ff26a027000 R11: 0000000000000246 R12: 0000000000067ece
R13: 00007ffd6b36bad0 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>

Allocated by task 9119:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:433 [inline]
 __kasan_slab_alloc+0xb1/0xe0 mm/kasan/common.c:466
 kasan_slab_alloc include/linux/kasan.h:217 [inline]
 slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:550
 slab_alloc_node mm/slub.c:3240 [inline]
 slab_alloc mm/slub.c:3248 [inline]
 kmem_cache_alloc+0xf5/0x200 mm/slub.c:3253
 skb_clone+0x1d1/0x360 net/core/skbuff.c:1547
 sk_psock_verdict_recv+0x53/0x840 net/core/skmsg.c:1182
 unix_read_sock+0x132/0x370 net/unix/af_unix.c:2433
 sk_psock_verdict_data_ready+0x147/0x1a0 net/core/skmsg.c:1225
 unix_dgram_sendmsg+0x15fa/0x2090 net/unix/af_unix.c:1947
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431
 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485
 __sys_sendmsg net/socket.c:2514 [inline]
 __do_sys_sendmsg net/socket.c:2523 [inline]
 __se_sys_sendmsg+0x19a/0x260 net/socket.c:2521
 __x64_sys_sendmsg+0x7b/0x90 net/socket.c:2521
 x64_sys_call+0x16a/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 337:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x126/0x160 mm/kasan/common.c:365
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1723 [inline]
 slab_free_freelist_hook+0xbd/0x190 mm/slub.c:1749
 slab_free mm/slub.c:3519 [inline]
 kmem_cache_free+0x116/0x2e0 mm/slub.c:3535
 kfree_skbmem+0x104/0x170
 __kfree_skb net/core/skbuff.c:758 [inline]
 kfree_skb_reason net/core/skbuff.c:778 [inline]
 kfree_skb+0xc2/0x360 net/core/skbuff.c:792
 sock_drop include/linux/skmsg.h:312 [inline]
 sk_psock_backlog+0xc21/0xd90 net/core/skmsg.c:681
 process_one_work+0x6bb/0xc10 kernel/workqueue.c:2325
 worker_thread+0xad5/0x12a0 kernel/workqueue.c:2472
 kthread+0x421/0x510 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300

The buggy address belongs to the object at ffff8881263ff3c0
 which belongs to the cache skbuff_head_cache of size 248
The buggy address is located 0 bytes inside of
 248-byte region [ffff8881263ff3c0, ffff8881263ff4b8)
The buggy address belongs to the page:
page:ffffea000498ffc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1263ff
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea0004f3f900 0000000600000006 ffff8881081b3980
raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 7493, ts 357553264999, free_ts 356684031633
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1a3/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x3550/0x35d0 mm/page_alloc.c:4485
 __alloc_pages+0x27e/0x8f0 mm/page_alloc.c:5779
 allocate_slab mm/slub.c:1932 [inline]
 new_slab+0x9a/0x4e0 mm/slub.c:1995
 ___slab_alloc+0x39e/0x830 mm/slub.c:3028
 __slab_alloc+0x4a/0x90 mm/slub.c:3115
 slab_alloc_node mm/slub.c:3206 [inline]
 slab_alloc mm/slub.c:3248 [inline]
 kmem_cache_alloc+0x134/0x200 mm/slub.c:3253
 skb_clone+0x1d1/0x360 net/core/skbuff.c:1547
 ____bpf_clone_redirect net/core/filter.c:2424 [inline]
 bpf_clone_redirect+0xa6/0x390 net/core/filter.c:2411
 bpf_prog_d241a00e15f251e5+0x512/0x98c
 bpf_dispatcher_nop_func include/linux/bpf.h:785 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x478/0xa10 net/bpf/test_run.c:119
 bpf_prog_test_run_skb+0xb41/0x1420 net/bpf/test_run.c:663
 bpf_prog_test_run+0x3b0/0x630 kernel/bpf/syscall.c:3348
 __sys_bpf+0x525/0x760 kernel/bpf/syscall.c:4651
 __do_sys_bpf kernel/bpf/syscall.c:4737 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4735 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:4735
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x7c8/0x7d0 mm/page_alloc.c:3534
 free_unref_page_list+0x14b/0xa60 mm/page_alloc.c:3671
 release_pages+0x1310/0x1370 mm/swap.c:1009
 free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:320
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:338
 exit_mmap+0x40d/0x940 mm/mmap.c:3218
 __mmput+0x95/0x310 kernel/fork.c:1179
 mmput+0x5b/0x170 kernel/fork.c:1202
 exit_mm kernel/exit.c:552 [inline]
 do_exit+0xb9c/0x2ca0 kernel/exit.c:865
 __do_sys_exit kernel/exit.c:969 [inline]
 __se_sys_exit kernel/exit.c:967 [inline]
 __ia32_sys_exit+0x0/0x40 kernel/exit.c:967
 x64_sys_call+0x1cc/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:61
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff8881263ff280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881263ff300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
>ffff8881263ff380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
                                           ^
 ffff8881263ff400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881263ff480: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
==================================================================