[v6.1] KASAN: use-after-free Read in kernfs_add_one

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ca87e77a2ef8 Linux 6.1.34
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1494215b280000
kernel config: https://syzkaller.appspot.com/x/.config?x=c188e92022a334b
dashboard link: https://syzkaller.appspot.com/bug?extid=91af4b4fcb0a6faed7c0
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f48d514c343c/disk-ca87e77a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/563336f1f216/vmlinux-ca87e77a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2254afa3642b/bzImage-ca87e77a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+91af4b...@syzkaller.appspotmail.com

usb 3-1: Direct firmware load for ueagle-atm/adi930.fw failed with error -2
usb 3-1: Falling back to sysfs fallback for: ueagle-atm/adi930.fw
==================================================================
BUG: KASAN: use-after-free in kernfs_root fs/kernfs/kernfs-internal.h:66 [inline]
BUG: KASAN: use-after-free in kernfs_next_descendant_post fs/kernfs/dir.c:1299 [inline]
BUG: KASAN: use-after-free in kernfs_activate fs/kernfs/dir.c:1354 [inline]
BUG: KASAN: use-after-free in kernfs_add_one+0x4ae/0x850 fs/kernfs/dir.c:786
Read of size 8 at addr ffff88801766ab10 by task kworker/0:4/3637

CPU: 0 PID: 3637 Comm: kworker/0:4 Not tainted 6.1.34-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Workqueue: events request_firmware_work_func
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
print_address_description mm/kasan/report.c:284 [inline]
print_report+0x15f/0x4f0 mm/kasan/report.c:395
kasan_report+0x136/0x160 mm/kasan/report.c:495
kernfs_root fs/kernfs/kernfs-internal.h:66 [inline]
kernfs_next_descendant_post fs/kernfs/dir.c:1299 [inline]
kernfs_activate fs/kernfs/dir.c:1354 [inline]
kernfs_add_one+0x4ae/0x850 fs/kernfs/dir.c:786
kernfs_create_dir_ns+0x1c0/0x230 fs/kernfs/dir.c:1031
sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:63 [inline]
kobject_add_internal+0x6df/0xd10 lib/kobject.c:231
kobject_add_varg lib/kobject.c:366 [inline]
kobject_add+0x14e/0x210 lib/kobject.c:418
device_add+0x476/0xfd0 drivers/base/core.c:3599
fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:82 [inline]
fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:158 [inline]
firmware_fallback_sysfs+0x2fd/0x940 drivers/base/firmware_loader/fallback.c:234
_request_firmware+0xc13/0x1200 drivers/base/firmware_loader/main.c:856
request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1105
process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x26e/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>

Allocated by task 3637:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
__kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x50/0x370 mm/slab.h:737
slab_alloc_node mm/slub.c:3398 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
kmem_cache_zalloc include/linux/slab.h:679 [inline]
__kernfs_new_node+0xdb/0x730 fs/kernfs/dir.c:608
kernfs_new_node fs/kernfs/dir.c:670 [inline]
kernfs_create_dir_ns+0x90/0x230 fs/kernfs/dir.c:1021
sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:63 [inline]
kobject_add_internal+0x6df/0xd10 lib/kobject.c:231
kobject_add_varg lib/kobject.c:366 [inline]
kobject_add+0x14e/0x210 lib/kobject.c:418
device_add+0x476/0xfd0 drivers/base/core.c:3599
fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:82 [inline]
fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:158 [inline]
firmware_fallback_sysfs+0x2fd/0x940 drivers/base/firmware_loader/fallback.c:234
_request_firmware+0xc13/0x1200 drivers/base/firmware_loader/main.c:856
request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1105
process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x26e/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Freed by task 3640:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1724 [inline]
slab_free_freelist_hook mm/slub.c:1750 [inline]
slab_free mm/slub.c:3661 [inline]
kmem_cache_free+0x292/0x510 mm/slub.c:3683
kernfs_put+0x325/0x4a0 fs/kernfs/dir.c:562
__kernfs_remove+0x5fc/0x710 fs/kernfs/dir.c:1453
kernfs_remove+0x76/0x90 fs/kernfs/dir.c:1473
__kobject_del+0xe2/0x310 lib/kobject.c:596
kobject_del+0x41/0x60 lib/kobject.c:619
device_del+0x9f6/0xbd0 drivers/base/core.c:3863
usb_disconnect+0x58f/0x8c0 drivers/usb/core/hub.c:2264
hub_port_connect drivers/usb/core/hub.c:5199 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5499 [inline]
port_event drivers/usb/core/hub.c:5655 [inline]
hub_event+0x1dfa/0x57b0 drivers/usb/core/hub.c:5737
process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
process_scheduled_works kernel/workqueue.c:2352 [inline]
worker_thread+0xd1c/0x1210 kernel/workqueue.c:2438
kthread+0x26e/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

The buggy address belongs to the object at ffff88801766aae0
which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 48 bytes inside of
168-byte region [ffff88801766aae0, ffff88801766ab88)

The buggy address belongs to the physical page:
page:ffffea00005d9a80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1766a
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0001e29e00 dead000000000006 ffff88801261ac80
raw: 0000000000000000 0000000080110011 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 3591, tgid 3591 (syz-executor.1), ts 266260478693, free_ts 266068867917
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2533
prep_new_page mm/page_alloc.c:2540 [inline]
get_page_from_freelist+0x32ed/0x3480 mm/page_alloc.c:4292
__alloc_pages+0x28d/0x770 mm/page_alloc.c:5559
alloc_slab_page+0x6a/0x150 mm/slub.c:1794
allocate_slab mm/slub.c:1939 [inline]
new_slab+0x84/0x2d0 mm/slub.c:1992
___slab_alloc+0xa71/0x1080 mm/slub.c:3180
__slab_alloc mm/slub.c:3279 [inline]
slab_alloc_node mm/slub.c:3364 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x1a5/0x2d0 mm/slub.c:3422
kmem_cache_zalloc include/linux/slab.h:679 [inline]
__kernfs_new_node+0xdb/0x730 fs/kernfs/dir.c:608
kernfs_new_node+0x95/0x160 fs/kernfs/dir.c:670
__kernfs_create_file+0x45/0x2e0 fs/kernfs/file.c:1043
sysfs_add_file_mode_ns+0x246/0x300 fs/sysfs/file.c:294
create_files fs/sysfs/group.c:64 [inline]
internal_create_group+0x545/0xed0 fs/sysfs/group.c:148
internal_create_groups fs/sysfs/group.c:188 [inline]
sysfs_create_groups+0x52/0x110 fs/sysfs/group.c:214
create_dir lib/kobject.c:68 [inline]
kobject_add_internal+0x725/0xd10 lib/kobject.c:231
kobject_add_varg lib/kobject.c:366 [inline]
kobject_init_and_add+0x120/0x190 lib/kobject.c:449
netdev_queue_add_kobject net/core/net-sysfs.c:1666 [inline]
netdev_queue_update_kobjects+0x1f2/0x480 net/core/net-sysfs.c:1718
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1460 [inline]
free_pcp_prepare mm/page_alloc.c:1510 [inline]
free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3388
free_unref_page+0x98/0x570 mm/page_alloc.c:3484
qlist_free_all+0x22/0x60 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x162/0x180 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x50/0x370 mm/slab.h:737
slab_alloc_node mm/slub.c:3398 [inline]
kmem_cache_alloc_node+0x136/0x310 mm/slub.c:3443
__alloc_skb+0xdf/0x620 net/core/skbuff.c:497
alloc_skb include/linux/skbuff.h:1268 [inline]
nlmsg_new include/net/netlink.h:970 [inline]
rtmsg_ifinfo_build_skb+0x81/0x180 net/core/rtnetlink.c:3911
rtmsg_ifinfo_event net/core/rtnetlink.c:3947 [inline]
rtnetlink_event+0xee/0x1b0 net/core/rtnetlink.c:6148
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:455
call_netdevice_notifiers_info net/core/dev.c:1945 [inline]
netdev_lower_state_changed+0x1b9/0x260 net/core/dev.c:8305
team_lower_state_changed drivers/net/team/team.c:89 [inline]
team_refresh_port_linkup drivers/net/team/team.c:99 [inline]
__team_port_change_send+0x215/0x5b0 drivers/net/team/team.c:2921
__team_port_change_port_added drivers/net/team/team.c:2974 [inline]
team_port_add drivers/net/team/team.c:1289 [inline]
team_add_slave+0x1ffc/0x2620 drivers/net/team/team.c:1985
do_set_master net/core/rtnetlink.c:2578 [inline]
do_setlink+0xd92/0x3e60 net/core/rtnetlink.c:2781
__rtnl_newlink net/core/rtnetlink.c:3553 [inline]
rtnl_newlink+0x16f7/0x1fa0 net/core/rtnetlink.c:3600

Memory state around the buggy address:
ffff88801766aa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88801766aa80: 00 00 00 00 fc fc fc fc fc fc fc fc fa fb fb fb
>ffff88801766ab00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88801766ab80: fb fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb
ffff88801766ac00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
==================================================================


---
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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b911329317b4 Linux 5.15.133
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16cf2a21680000
kernel config: https://syzkaller.appspot.com/x/.config?x=a9c9f0083f439f72
dashboard link: https://syzkaller.appspot.com/bug?extid=2b1e09de67485a21a763
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:

disk image: https://storage.googleapis.com/syzbot-assets/46530025981a/disk-b9113293.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d27830145a50/vmlinux-b9113293.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ee1d0b88a1d9/bzImage-b9113293.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+2b1e09...@syzkaller.appspotmail.com

usb 5-1: Direct firmware load for ueagle-atm/eagleII.fw failed with error -2
usb 5-1: Falling back to sysfs fallback for: ueagle-atm/eagleII.fw
==================================================================
BUG: KASAN: use-after-free in kernfs_root fs/kernfs/kernfs-internal.h:48 [inline]
BUG: KASAN: use-after-free in kernfs_add_one+0x491/0x640 fs/kernfs/dir.c:775
Read of size 8 at addr ffff8880701ba030 by task kworker/0:9/17146

CPU: 0 PID: 17146 Comm: kworker/0:9 Not tainted 5.15.133-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023

Workqueue: events request_firmware_work_func
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106

print_address_description+0x63/0x3b0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
kernfs_root fs/kernfs/kernfs-internal.h:48 [inline]
kernfs_add_one+0x491/0x640 fs/kernfs/dir.c:775
kernfs_create_dir_ns+0x1c0/0x230 fs/kernfs/dir.c:1003
sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:89 [inline]
kobject_add_internal+0x6e0/0xe00 lib/kobject.c:263
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x14e/0x210 lib/kobject.c:450
device_add+0x476/0xfd0 drivers/base/core.c:3329
fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:507 [inline]
fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:583 [inline]
firmware_fallback_sysfs+0x3f0/0xc90 drivers/base/firmware_loader/fallback.c:659
_request_firmware+0xbb1/0x1200 drivers/base/firmware_loader/main.c:848
request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1097
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>

Allocated by task 17146:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3220 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
kmem_cache_zalloc include/linux/slab.h:711 [inline]
__kernfs_new_node+0xdb/0x750 fs/kernfs/dir.c:593
kernfs_new_node fs/kernfs/dir.c:657 [inline]
kernfs_create_dir_ns+0x90/0x230 fs/kernfs/dir.c:993
sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:89 [inline]
kobject_add_internal+0x6e0/0xe00 lib/kobject.c:263
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x14e/0x210 lib/kobject.c:450
device_add+0x476/0xfd0 drivers/base/core.c:3329
fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:507 [inline]
fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:583 [inline]
firmware_fallback_sysfs+0x3f0/0xc90 drivers/base/firmware_loader/fallback.c:659
_request_firmware+0xbb1/0x1200 drivers/base/firmware_loader/main.c:848
request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1097
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Freed by task 12528:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x80 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1705 [inline]
slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731
slab_free mm/slub.c:3499 [inline]
kmem_cache_free+0x91/0x1f0 mm/slub.c:3515
kernfs_put+0x325/0x4a0 fs/kernfs/dir.c:547
__kernfs_remove+0x99e/0xc80 fs/kernfs/dir.c:1381
kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1394
__kobject_del+0xe2/0x310 lib/kobject.c:628
kobject_del+0x41/0x60 lib/kobject.c:651
device_del+0x9fe/0xbd0 drivers/base/core.c:3594
usb_disconnect+0x58f/0x8c0 drivers/usb/core/hub.c:2257
hub_port_connect drivers/usb/core/hub.c:5262 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5558 [inline]
port_event drivers/usb/core/hub.c:5704 [inline]
hub_event+0x1d58/0x54b0 drivers/usb/core/hub.c:5786
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
process_scheduled_works kernel/workqueue.c:2373 [inline]
worker_thread+0xdcf/0x1280 kernel/workqueue.c:2459
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

The buggy address belongs to the object at ffff8880701ba000

which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 48 bytes inside of

168-byte region [ffff8880701ba000, ffff8880701ba0a8)
The buggy address belongs to the page:
page:ffffea0001c06e80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x701ba

flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)

raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888011dddb40

raw: 0000000000000000 0000000080110011 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 17146, ts 2575486055782, free_ts 2575343735190
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159
__alloc_pages+0x272/0x700 mm/page_alloc.c:5421
alloc_slab_page mm/slub.c:1775 [inline]
allocate_slab mm/slub.c:1912 [inline]
new_slab+0xbb/0x4b0 mm/slub.c:1975
___slab_alloc+0x6f6/0xe10 mm/slub.c:3008
__slab_alloc mm/slub.c:3095 [inline]
slab_alloc_node mm/slub.c:3186 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233
kmem_cache_zalloc include/linux/slab.h:711 [inline]
__kernfs_new_node+0xdb/0x750 fs/kernfs/dir.c:593
kernfs_new_node fs/kernfs/dir.c:657 [inline]
kernfs_create_dir_ns+0x90/0x230 fs/kernfs/dir.c:993
sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:89 [inline]
kobject_add_internal+0x6e0/0xe00 lib/kobject.c:263
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x14e/0x210 lib/kobject.c:450
device_add+0x476/0xfd0 drivers/base/core.c:3329
fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:507 [inline]
fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:583 [inline]
firmware_fallback_sysfs+0x3f0/0xc90 drivers/base/firmware_loader/fallback.c:659
_request_firmware+0xbb1/0x1200 drivers/base/firmware_loader/main.c:848
request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1097
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457

page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]

free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317
free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396
__vunmap+0x8d4/0xa20 mm/vmalloc.c:2621
free_work+0x57/0x80 mm/vmalloc.c:95
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Memory state around the buggy address:

ffff8880701b9f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880701b9f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880701ba000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880701ba080: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
ffff8880701ba100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

==================================================================


---
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