==================================================================
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 ffff88811bb2e36c by task syz.1.646/2329

CPU: 1 PID: 2329 Comm: syz.1.646 Not tainted 5.15.167-syzkaller-02003-g5e4635681cf1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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:769 [inline]
 __sk_psock_zap_ingress net/core/skmsg.c:787 [inline]
 sk_psock_stop+0x44c/0x4d0 net/core/skmsg.c:805
 sk_psock_drop+0x219/0x310 net/core/skmsg.c:844
 sk_psock_put include/linux/skmsg.h:458 [inline]
 sock_map_unref+0x48f/0x4d0 net/core/sock_map.c:183
 __sock_map_delete net/core/sock_map.c:425 [inline]
 sock_map_delete_from_link net/core/sock_map.c:438 [inline]
 sock_map_unlink net/core/sock_map.c:1496 [inline]
 sock_map_remove_links+0x41c/0x650 net/core/sock_map.c:1511
 sock_map_close+0x114/0x530 net/core/sock_map.c:1548
 unix_release+0x82/0xc0 net/unix/af_unix.c:936
 __sock_release net/socket.c:649 [inline]
 sock_close+0xdf/0x270 net/socket.c:1336
 __fput+0x228/0x8c0 fs/file_table.c:280
 ____fput+0x15/0x20 fs/file_table.c:308
 task_work_run+0x129/0x190 kernel/task_work.c:188
 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: 0033:0x7f4c5c266ff9
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:00007fff44eff1c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f4c5c420a80 RCX: 00007f4c5c266ff9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f4c5c420a80 R08: 0000000000000000 R09: 00007fff44eff4bf
R10: 000000000003fd98 R11: 0000000000000246 R12: 000000000001840d
R13: 00007fff44eff2d0 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>

Allocated by task 2330:
 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:1183
 unix_read_sock+0x132/0x370 net/unix/af_unix.c:2428
 sk_psock_verdict_data_ready+0x147/0x1a0 net/core/skmsg.c:1226
 unix_dgram_sendmsg+0x15fa/0x2090 net/unix/af_unix.c:1942
 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 2018:
 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:682
 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:287

The buggy address belongs to the object at ffff88811bb2e280
 which belongs to the cache skbuff_head_cache of size 248
The buggy address is located 236 bytes inside of
 248-byte region [ffff88811bb2e280, ffff88811bb2e378)
The buggy address belongs to the page:
page:ffffea00046ecb80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11bb2e
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea00044dff40 0000000400000004 ffff8881081b2600
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 473, ts 54200722803, free_ts 54096735353
 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
 kmem_cache_alloc_node include/linux/slab.h:474 [inline]
 __alloc_skb+0xbe/0x550 net/core/skbuff.c:416
 alloc_skb include/linux/skbuff.h:1183 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 __neigh_notify+0x7d/0x120 net/core/neighbour.c:3375
 neigh_cleanup_and_release+0x2c/0x1b0 net/core/neighbour.c:101
 neigh_flush_dev+0x693/0x850 net/core/neighbour.c:374
 __neigh_ifdown+0x41/0x3d0 net/core/neighbour.c:391
 neigh_carrier_down+0x22/0x30 net/core/neighbour.c:401
 ndisc_netdev_event+0x297/0x400 net/ipv6/ndisc.c:1832
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x8c/0xf0 kernel/notifier.c:391
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+0xe8/0x750 mm/page_alloc.c:3616
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x61/0xf0 mm/page_alloc.c:5855
 __vunmap+0x7bc/0x8f0 mm/vmalloc.c:2652
 __vfree mm/vmalloc.c:2700 [inline]
 vfree+0x7f/0xb0 mm/vmalloc.c:2731
 module_memfree+0x17/0x30 kernel/module.c:2150
 bpf_jit_free_exec+0x15/0x20 kernel/bpf/core.c:867
 bpf_jit_binary_free kernel/bpf/core.c:914 [inline]
 bpf_jit_free+0x98/0x240 kernel/bpf/core.c:927
 bpf_prog_free_deferred+0x4ea/0x730 kernel/bpf/core.c:2292
 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:287

Memory state around the buggy address:
 ffff88811bb2e200: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
 ffff88811bb2e280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811bb2e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
                                                          ^
 ffff88811bb2e380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
 ffff88811bb2e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
==================================================================
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: 1 PID: 2329 Comm: syz.1.646 Tainted: G    B             5.15.167-syzkaller-02003-g5e4635681cf1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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:769 [inline]
 __sk_psock_zap_ingress net/core/skmsg.c:787 [inline]
 sk_psock_stop+0x44c/0x4d0 net/core/skmsg.c:805
 sk_psock_drop+0x219/0x310 net/core/skmsg.c:844
 sk_psock_put include/linux/skmsg.h:458 [inline]
 sock_map_unref+0x48f/0x4d0 net/core/sock_map.c:183
 __sock_map_delete net/core/sock_map.c:425 [inline]
 sock_map_delete_from_link net/core/sock_map.c:438 [inline]
 sock_map_unlink net/core/sock_map.c:1496 [inline]
 sock_map_remove_links+0x41c/0x650 net/core/sock_map.c:1511
 sock_map_close+0x114/0x530 net/core/sock_map.c:1548
 unix_release+0x82/0xc0 net/unix/af_unix.c:936
 __sock_release net/socket.c:649 [inline]
 sock_close+0xdf/0x270 net/socket.c:1336
 __fput+0x228/0x8c0 fs/file_table.c:280
 ____fput+0x15/0x20 fs/file_table.c:308
 task_work_run+0x129/0x190 kernel/task_work.c:188
 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: 0033:0x7f4c5c266ff9
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:00007fff44eff1c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f4c5c420a80 RCX: 00007f4c5c266ff9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f4c5c420a80 R08: 0000000000000000 R09: 00007fff44eff4bf
R10: 000000000003fd98 R11: 0000000000000246 R12: 000000000001840d
R13: 00007fff44eff2d0 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>

Allocated by task 2330:
 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:1183
 unix_read_sock+0x132/0x370 net/unix/af_unix.c:2428
 sk_psock_verdict_data_ready+0x147/0x1a0 net/core/skmsg.c:1226
 unix_dgram_sendmsg+0x15fa/0x2090 net/unix/af_unix.c:1942
 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 2018:
 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:682
 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:287

The buggy address belongs to the object at ffff88811bb2e280
 which belongs to the cache skbuff_head_cache of size 248
The buggy address is located 0 bytes inside of
 248-byte region [ffff88811bb2e280, ffff88811bb2e378)
The buggy address belongs to the page:
page:ffffea00046ecb80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11bb2e
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea00044dff40 0000000400000004 ffff8881081b2600
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 473, ts 54200722803, free_ts 54096735353
 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
 kmem_cache_alloc_node include/linux/slab.h:474 [inline]
 __alloc_skb+0xbe/0x550 net/core/skbuff.c:416
 alloc_skb include/linux/skbuff.h:1183 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 __neigh_notify+0x7d/0x120 net/core/neighbour.c:3375
 neigh_cleanup_and_release+0x2c/0x1b0 net/core/neighbour.c:101
 neigh_flush_dev+0x693/0x850 net/core/neighbour.c:374
 __neigh_ifdown+0x41/0x3d0 net/core/neighbour.c:391
 neigh_carrier_down+0x22/0x30 net/core/neighbour.c:401
 ndisc_netdev_event+0x297/0x400 net/ipv6/ndisc.c:1832
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x8c/0xf0 kernel/notifier.c:391
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+0xe8/0x750 mm/page_alloc.c:3616
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x61/0xf0 mm/page_alloc.c:5855
 __vunmap+0x7bc/0x8f0 mm/vmalloc.c:2652
 __vfree mm/vmalloc.c:2700 [inline]
 vfree+0x7f/0xb0 mm/vmalloc.c:2731
 module_memfree+0x17/0x30 kernel/module.c:2150
 bpf_jit_free_exec+0x15/0x20 kernel/bpf/core.c:867
 bpf_jit_binary_free kernel/bpf/core.c:914 [inline]
 bpf_jit_free+0x98/0x240 kernel/bpf/core.c:927
 bpf_prog_free_deferred+0x4ea/0x730 kernel/bpf/core.c:2292
 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:287

Memory state around the buggy address:
 ffff88811bb2e180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811bb2e200: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
>ffff88811bb2e280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88811bb2e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
 ffff88811bb2e380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
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