==================================================================
BUG: KASAN: slab-out-of-bounds in __cpa_addr arch/x86/mm/pat/set_memory.c:309 [inline]
BUG: KASAN: slab-out-of-bounds in __cpa_addr+0x1d3/0x220 arch/x86/mm/pat/set_memory.c:306
Read of size 8 at addr ffff888054da2ef8 by task syz.3.1044/10316

CPU: 0 UID: 0 PID: 10316 Comm: syz.3.1044 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 __cpa_addr arch/x86/mm/pat/set_memory.c:309 [inline]
 __cpa_addr+0x1d3/0x220 arch/x86/mm/pat/set_memory.c:306
 cpa_flush+0x28b/0x8a0 arch/x86/mm/pat/set_memory.c:449
 change_page_attr_set_clr+0x34e/0x4a0 arch/x86/mm/pat/set_memory.c:2115
 cpa_set_pages_array arch/x86/mm/pat/set_memory.c:2137 [inline]
 _set_pages_array+0x1ab/0x2c0 arch/x86/mm/pat/set_memory.c:2521
 drm_gem_shmem_get_pages_locked+0x384/0x490 drivers/gpu/drm/drm_gem_shmem_helper.c:214
 drm_gem_shmem_mmap drivers/gpu/drm/drm_gem_shmem_helper.c:646 [inline]
 drm_gem_shmem_mmap+0xc9/0x550 drivers/gpu/drm/drm_gem_shmem_helper.c:620
 drm_gem_mmap_obj+0x1b5/0x560 drivers/gpu/drm/drm_gem.c:1167
 drm_gem_mmap+0x40b/0x620 drivers/gpu/drm/drm_gem.c:1245
 vfs_mmap include/linux/fs.h:2405 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2413 [inline]
 __mmap_new_vma mm/vma.c:2476 [inline]
 __mmap_region+0x1309/0x27a0 mm/vma.c:2670
 mmap_region+0x1ab/0x3f0 mm/vma.c:2740
 do_mmap+0xa3e/0x1210 mm/mmap.c:558
 vm_mmap_pgoff+0x29e/0x470 mm/util.c:581
 ksys_mmap_pgoff+0x32c/0x5c0 mm/mmap.c:604
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbb98f8eec9
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:00007fbb99d7f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fbb991e5fa0 RCX: 00007fbb98f8eec9
RDX: 0000000000000004 RSI: 0000000000004000 RDI: 0000200000001000
RBP: 00007fbb99011f91 R08: 0000000000000005 R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbb991e6038 R14: 00007fbb991e5fa0 R15: 00007ffc80c26ba8
 </TASK>

Allocated by task 10316:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5627 [inline]
 __kvmalloc_node_noprof+0x3a3/0x9c0 mm/slub.c:7081
 kvmalloc_array_node_noprof include/linux/slab.h:1122 [inline]
 drm_gem_get_pages+0x144/0xa10 drivers/gpu/drm/drm_gem.c:647
 drm_gem_shmem_get_pages_locked+0x1e6/0x490 drivers/gpu/drm/drm_gem_shmem_helper.c:200
 drm_gem_shmem_mmap drivers/gpu/drm/drm_gem_shmem_helper.c:646 [inline]
 drm_gem_shmem_mmap+0xc9/0x550 drivers/gpu/drm/drm_gem_shmem_helper.c:620
 drm_gem_mmap_obj+0x1b5/0x560 drivers/gpu/drm/drm_gem.c:1167
 drm_gem_mmap+0x40b/0x620 drivers/gpu/drm/drm_gem.c:1245
 vfs_mmap include/linux/fs.h:2405 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2413 [inline]
 __mmap_new_vma mm/vma.c:2476 [inline]
 __mmap_region+0x1309/0x27a0 mm/vma.c:2670
 mmap_region+0x1ab/0x3f0 mm/vma.c:2740
 do_mmap+0xa3e/0x1210 mm/mmap.c:558
 vm_mmap_pgoff+0x29e/0x470 mm/util.c:581
 ksys_mmap_pgoff+0x32c/0x5c0 mm/mmap.c:604
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888054da2e00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 0 bytes to the right of
 allocated 248-byte region [ffff888054da2e00, ffff888054da2ef8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x54da2
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ffa6b40 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6b40 0000000000000000 dead000000000001
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0001536881 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5831, tgid 5831 (syz-executor), ts 108226446600, free_ts 36114020838
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3039 [inline]
 allocate_slab mm/slub.c:3212 [inline]
 new_slab+0x24a/0x360 mm/slub.c:3266
 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4636
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4755
 __slab_alloc_node mm/slub.c:4831 [inline]
 slab_alloc_node mm/slub.c:5253 [inline]
 __do_kmalloc_node mm/slub.c:5626 [inline]
 __kmalloc_noprof+0x501/0x880 mm/slub.c:5639
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 new_dir fs/proc/proc_sysctl.c:966 [inline]
 get_subdir fs/proc/proc_sysctl.c:1010 [inline]
 sysctl_mkdir_p fs/proc/proc_sysctl.c:1320 [inline]
 __register_sysctl_table+0xea2/0x1900 fs/proc/proc_sysctl.c:1395
 mpls_dev_sysctl_register+0x185/0x2a0 net/mpls/af_mpls.c:1405
 mpls_add_dev net/mpls/af_mpls.c:1460 [inline]
 mpls_dev_notify+0x4ab/0xa20 net/mpls/af_mpls.c:1600
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 register_netdevice+0x182e/0x2270 net/core/dev.c:11332
 veth_newlink+0x316/0xa00 drivers/net/veth.c:1855
 rtnl_newlink_create net/core/rtnetlink.c:3833 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3950 [inline]
 rtnl_newlink+0xc45/0x2000 net/core/rtnetlink.c:4065
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906
 __free_pages mm/page_alloc.c:5302 [inline]
 free_contig_range+0x183/0x4b0 mm/page_alloc.c:7146
 destroy_args+0xb69/0x12e0 mm/debug_vm_pgtable.c:958
 debug_vm_pgtable+0x1a32/0x3640 mm/debug_vm_pgtable.c:1345
 do_one_initcall+0x123/0x6e0 init/main.c:1283
 do_initcall_level init/main.c:1345 [inline]
 do_initcalls init/main.c:1361 [inline]
 do_basic_setup init/main.c:1380 [inline]
 kernel_init_freeable+0x5c8/0x920 init/main.c:1593
 kernel_init+0x1c/0x2b0 init/main.c:1483
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888054da2d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888054da2e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888054da2e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
                                                                ^
 ffff888054da2f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888054da2f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in __cpa_addr arch/x86/mm/pat/set_memory.c:309 [inline]
BUG: KASAN: slab-out-of-bounds in __cpa_addr+0x1d3/0x220 arch/x86/mm/pat/set_memory.c:306
Read of size 8 at addr ffff888054da2ef8 by task syz.3.1044/10316

CPU: 1 UID: 0 PID: 10316 Comm: syz.3.1044 Tainted: G    B               syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 __cpa_addr arch/x86/mm/pat/set_memory.c:309 [inline]
 __cpa_addr+0x1d3/0x220 arch/x86/mm/pat/set_memory.c:306
 cpa_flush+0x28b/0x8a0 arch/x86/mm/pat/set_memory.c:449
 change_page_attr_set_clr+0x34e/0x4a0 arch/x86/mm/pat/set_memory.c:2115
 _set_pages_array+0x20a/0x2c0 arch/x86/mm/pat/set_memory.c:2524
 drm_gem_shmem_get_pages_locked+0x384/0x490 drivers/gpu/drm/drm_gem_shmem_helper.c:214
 drm_gem_shmem_mmap drivers/gpu/drm/drm_gem_shmem_helper.c:646 [inline]
 drm_gem_shmem_mmap+0xc9/0x550 drivers/gpu/drm/drm_gem_shmem_helper.c:620
 drm_gem_mmap_obj+0x1b5/0x560 drivers/gpu/drm/drm_gem.c:1167
 drm_gem_mmap+0x40b/0x620 drivers/gpu/drm/drm_gem.c:1245
 vfs_mmap include/linux/fs.h:2405 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2413 [inline]
 __mmap_new_vma mm/vma.c:2476 [inline]
 __mmap_region+0x1309/0x27a0 mm/vma.c:2670
 mmap_region+0x1ab/0x3f0 mm/vma.c:2740
 do_mmap+0xa3e/0x1210 mm/mmap.c:558
 vm_mmap_pgoff+0x29e/0x470 mm/util.c:581
 ksys_mmap_pgoff+0x32c/0x5c0 mm/mmap.c:604
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbb98f8eec9
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:00007fbb99d7f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fbb991e5fa0 RCX: 00007fbb98f8eec9
RDX: 0000000000000004 RSI: 0000000000004000 RDI: 0000200000001000
RBP: 00007fbb99011f91 R08: 0000000000000005 R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbb991e6038 R14: 00007fbb991e5fa0 R15: 00007ffc80c26ba8
 </TASK>

Allocated by task 10316:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5627 [inline]
 __kvmalloc_node_noprof+0x3a3/0x9c0 mm/slub.c:7081
 kvmalloc_array_node_noprof include/linux/slab.h:1122 [inline]
 drm_gem_get_pages+0x144/0xa10 drivers/gpu/drm/drm_gem.c:647
 drm_gem_shmem_get_pages_locked+0x1e6/0x490 drivers/gpu/drm/drm_gem_shmem_helper.c:200
 drm_gem_shmem_mmap drivers/gpu/drm/drm_gem_shmem_helper.c:646 [inline]
 drm_gem_shmem_mmap+0xc9/0x550 drivers/gpu/drm/drm_gem_shmem_helper.c:620
 drm_gem_mmap_obj+0x1b5/0x560 drivers/gpu/drm/drm_gem.c:1167
 drm_gem_mmap+0x40b/0x620 drivers/gpu/drm/drm_gem.c:1245
 vfs_mmap include/linux/fs.h:2405 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2413 [inline]
 __mmap_new_vma mm/vma.c:2476 [inline]
 __mmap_region+0x1309/0x27a0 mm/vma.c:2670
 mmap_region+0x1ab/0x3f0 mm/vma.c:2740
 do_mmap+0xa3e/0x1210 mm/mmap.c:558
 vm_mmap_pgoff+0x29e/0x470 mm/util.c:581
 ksys_mmap_pgoff+0x32c/0x5c0 mm/mmap.c:604
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888054da2e00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 0 bytes to the right of
 allocated 248-byte region [ffff888054da2e00, ffff888054da2ef8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x54da2
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ffa6b40 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6b40 0000000000000000 dead000000000001
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0001536881 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5831, tgid 5831 (syz-executor), ts 108226446600, free_ts 36114020838
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3039 [inline]
 allocate_slab mm/slub.c:3212 [inline]
 new_slab+0x24a/0x360 mm/slub.c:3266
 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4636
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4755
 __slab_alloc_node mm/slub.c:4831 [inline]
 slab_alloc_node mm/slub.c:5253 [inline]
 __do_kmalloc_node mm/slub.c:5626 [inline]
 __kmalloc_noprof+0x501/0x880 mm/slub.c:5639
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 new_dir fs/proc/proc_sysctl.c:966 [inline]
 get_subdir fs/proc/proc_sysctl.c:1010 [inline]
 sysctl_mkdir_p fs/proc/proc_sysctl.c:1320 [inline]
 __register_sysctl_table+0xea2/0x1900 fs/proc/proc_sysctl.c:1395
 mpls_dev_sysctl_register+0x185/0x2a0 net/mpls/af_mpls.c:1405
 mpls_add_dev net/mpls/af_mpls.c:1460 [inline]
 mpls_dev_notify+0x4ab/0xa20 net/mpls/af_mpls.c:1600
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 register_netdevice+0x182e/0x2270 net/core/dev.c:11332
 veth_newlink+0x316/0xa00 drivers/net/veth.c:1855
 rtnl_newlink_create net/core/rtnetlink.c:3833 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3950 [inline]
 rtnl_newlink+0xc45/0x2000 net/core/rtnetlink.c:4065
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906
 __free_pages mm/page_alloc.c:5302 [inline]
 free_contig_range+0x183/0x4b0 mm/page_alloc.c:7146
 destroy_args+0xb69/0x12e0 mm/debug_vm_pgtable.c:958
 debug_vm_pgtable+0x1a32/0x3640 mm/debug_vm_pgtable.c:1345
 do_one_initcall+0x123/0x6e0 init/main.c:1283
 do_initcall_level init/main.c:1345 [inline]
 do_initcalls init/main.c:1361 [inline]
 do_basic_setup init/main.c:1380 [inline]
 kernel_init_freeable+0x5c8/0x920 init/main.c:1593
 kernel_init+0x1c/0x2b0 init/main.c:1483
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888054da2d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888054da2e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888054da2e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
                                                                ^
 ffff888054da2f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888054da2f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================