==================================================================
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 ffff888024bb98f8 by task syz.4.2129/16474
CPU: 0 UID: 0 PID: 16474 Comm: syz.4.2129 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
__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: 0033:0x7fb3cc58efc9
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:00007fb3cd50f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fb3cc7e5fa0 RCX: 00007fb3cc58efc9
RDX: 0000000000000004 RSI: 0000000000004000 RDI: 0000200000001000
RBP: 00007fb3cc611f91 R08: 0000000000000003 R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb3cc7e6038 R14: 00007fb3cc7e5fa0 R15: 00007ffc7596fbd8
Allocated by task 16474:
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:5634 [inline]
__kvmalloc_node_noprof+0x3a3/0x9c0 mm/slub.c:7089
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 ffff888024bb9800
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 [ffff888024bb9800, ffff888024bb98f8)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24bb8
head: order:1 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 ffff88813ffa6b40 ffffea0000c90100 dead000000000006
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6b40 ffffea0000c90100 dead000000000006
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea000092ee01 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 5825, tgid 5825 (syz-executor), ts 111292038232, free_ts 111199324641
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:3046 [inline]
allocate_slab mm/slub.c:3219 [inline]
new_slab+0x24a/0x360 mm/slub.c:3273
___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4643
__slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4762
__slab_alloc_node mm/slub.c:4838 [inline]
slab_alloc_node mm/slub.c:5260 [inline]
__do_kmalloc_node mm/slub.c:5633 [inline]
__kmalloc_noprof+0x501/0x880 mm/slub.c:5646
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
fib_create_info+0x53f/0x46b0 net/ipv4/fib_semantics.c:1402
fib_table_insert+0x177/0x1c40 net/ipv4/fib_trie.c:1212
fib_magic+0x4d4/0x5c0 net/ipv4/fib_frontend.c:1134
fib_add_ifaddr+0x4d2/0x580 net/ipv4/fib_frontend.c:1178
fib_netdev_event+0x38a/0x710 net/ipv4/fib_frontend.c:1516
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]
__dev_notify_flags+0x12c/0x2e0 net/core/dev.c:9676
page last free pid 43 tgid 43 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
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4d/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:352
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4962 [inline]
slab_alloc_node mm/slub.c:5272 [inline]
__kmalloc_cache_noprof+0x274/0x780 mm/slub.c:5750
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
nsim_fib6_rt_create drivers/net/netdevsim/fib.c:547 [inline]
nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
nsim_fib_event_work+0x1938/0x6da0 drivers/net/netdevsim/fib.c:1493
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c5/0x780 kernel/kthread.c:463
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:
ffff888024bb9780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888024bb9800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888024bb9880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
^
ffff888024bb9900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888024bb9980: 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 ffff888024bb98f8 by task syz.4.2129/16474
CPU: 1 UID: 0 PID: 16474 Comm: syz.4.2129 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:
__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: 0033:0x7fb3cc58efc9
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:00007fb3cd50f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fb3cc7e5fa0 RCX: 00007fb3cc58efc9
RDX: 0000000000000004 RSI: 0000000000004000 RDI: 0000200000001000
RBP: 00007fb3cc611f91 R08: 0000000000000003 R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb3cc7e6038 R14: 00007fb3cc7e5fa0 R15: 00007ffc7596fbd8
Allocated by task 16474:
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:5634 [inline]
__kvmalloc_node_noprof+0x3a3/0x9c0 mm/slub.c:7089
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 ffff888024bb9800
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 [ffff888024bb9800, ffff888024bb98f8)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24bb8
head: order:1 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 ffff88813ffa6b40 ffffea0000c90100 dead000000000006
raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6b40 ffffea0000c90100 dead000000000006
head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea000092ee01 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 5825, tgid 5825 (syz-executor), ts 111292038232, free_ts 111199324641
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:3046 [inline]
allocate_slab mm/slub.c:3219 [inline]
new_slab+0x24a/0x360 mm/slub.c:3273
___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4643
__slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4762
__slab_alloc_node mm/slub.c:4838 [inline]
slab_alloc_node mm/slub.c:5260 [inline]
__do_kmalloc_node mm/slub.c:5633 [inline]
__kmalloc_noprof+0x501/0x880 mm/slub.c:5646
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
fib_create_info+0x53f/0x46b0 net/ipv4/fib_semantics.c:1402
fib_table_insert+0x177/0x1c40 net/ipv4/fib_trie.c:1212
fib_magic+0x4d4/0x5c0 net/ipv4/fib_frontend.c:1134
fib_add_ifaddr+0x4d2/0x580 net/ipv4/fib_frontend.c:1178
fib_netdev_event+0x38a/0x710 net/ipv4/fib_frontend.c:1516
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]
__dev_notify_flags+0x12c/0x2e0 net/core/dev.c:9676
page last free pid 43 tgid 43 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
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4d/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:352
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4962 [inline]
slab_alloc_node mm/slub.c:5272 [inline]
__kmalloc_cache_noprof+0x274/0x780 mm/slub.c:5750
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
nsim_fib6_rt_create drivers/net/netdevsim/fib.c:547 [inline]
nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
nsim_fib_event_work+0x1938/0x6da0 drivers/net/netdevsim/fib.c:1493
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c5/0x780 kernel/kthread.c:463
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:
ffff888024bb9780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888024bb9800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888024bb9880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
^
ffff888024bb9900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888024bb9980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================