syzbot
KASAN: use-after-free Read in f2fs_release_page (3)
Status:
premoderation: reported on 2026/09/11 19:10
Reported-by: syzbot+024c52715a4a42503e8a@syzkaller.appspotmail.com
First crash: 7d03h, last: 7d03h
Sample crash report:
overlayfs: failed to set xattr on upper
overlayfs: ...falling back to xino=off.
==================================================================
BUG: KASAN: use-after-free in F2FS_SB fs/f2fs/f2fs.h:1992 [inline]
BUG: KASAN: use-after-free in F2FS_I_SB fs/f2fs/f2fs.h:1997 [inline]
BUG: KASAN: use-after-free in F2FS_M_SB fs/f2fs/f2fs.h:2002 [inline]
BUG: KASAN: use-after-free in F2FS_P_SB fs/f2fs/f2fs.h:2007 [inline]
BUG: KASAN: use-after-free in f2fs_release_page+0x222/0x7c0 fs/f2fs/data.c:3773
Read of size 8 at addr ffff888111fbe3c8 by task syz.3.272/1496
CPU: 1 PID: 1496 Comm: syz.3.272 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
__dump_stack+0x21/0x30 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:427 [inline]
kasan_report+0x10f/0x150 mm/kasan/report.c:444
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
F2FS_SB fs/f2fs/f2fs.h:1992 [inline]
F2FS_I_SB fs/f2fs/f2fs.h:1997 [inline]
F2FS_M_SB fs/f2fs/f2fs.h:2002 [inline]
F2FS_P_SB fs/f2fs/f2fs.h:2007 [inline]
f2fs_release_page+0x222/0x7c0 fs/f2fs/data.c:3773
try_to_release_page+0x18d/0x1e0 mm/filemap.c:4082
shrink_page_list+0x25ff/0x5800 mm/vmscan.c:1793
shrink_inactive_list mm/vmscan.c:2338 [inline]
shrink_list mm/vmscan.c:2583 [inline]
shrink_lruvec+0x1297/0x3a40 mm/vmscan.c:5800
shrink_node_memcgs mm/vmscan.c:5992 [inline]
shrink_node+0x11ee/0x2a40 mm/vmscan.c:6022
shrink_zones mm/vmscan.c:6228 [inline]
do_try_to_free_pages+0x5a7/0x1580 mm/vmscan.c:6286
try_to_free_mem_cgroup_pages+0x261/0x610 mm/vmscan.c:6600
mem_cgroup_force_empty mm/memcontrol.c:3595 [inline]
mem_cgroup_force_empty_write+0x130/0x170 mm/memcontrol.c:3616
cgroup_file_write+0x294/0x560 kernel/cgroup/cgroup.c:4011
kernfs_fop_write_iter+0x2bd/0x400 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2212 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x831/0xfd0 fs/read_write.c:594
ksys_write+0x14a/0x260 fs/read_write.c:647
__do_sys_write fs/read_write.c:659 [inline]
__se_sys_write fs/read_write.c:656 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:656
x64_sys_call+0x8ef/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa3f4475159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa3f2ece028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa3f46fcfa0 RCX: 00007fa3f4475159
RDX: 0000000000000001 RSI: 00002000000002c0 RDI: 0000000000000007
RBP: 00007fa3f450c03b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa3f46fd038 R14: 00007fa3f46fcfa0 R15: 00007ffde92694b8
</TASK>
Allocated by task 1376:
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_kmalloc mm/kasan/common.c:512 [inline]
__kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:521
kasan_kmalloc include/linux/kasan.h:227 [inline]
__kmalloc_track_caller+0x13c/0x2c0 mm/slub.c:4959
kmalloc_reserve net/core/skbuff.c:357 [inline]
pskb_expand_head+0x123/0x1280 net/core/skbuff.c:1734
skb_ensure_writable+0x2e0/0x460 net/core/skbuff.c:5837
__bpf_try_make_writable net/core/filter.c:1676 [inline]
bpf_try_make_writable net/core/filter.c:1682 [inline]
bpf_try_make_head_writable net/core/filter.c:1690 [inline]
____bpf_clone_redirect net/core/filter.c:2465 [inline]
bpf_clone_redirect+0x1c6/0x460 net/core/filter.c:2434
0xffffffffa002a302
bpf_dispatcher_nop_func include/linux/bpf.h:786 [inline]
__bpf_prog_run include/linux/filter.h:628 [inline]
bpf_prog_run include/linux/filter.h:635 [inline]
bpf_test_run+0x351/0x900 net/bpf/test_run.c:119
bpf_prog_test_run_skb+0xa0c/0x1180 net/bpf/test_run.c:678
bpf_prog_test_run+0x3a5/0x5b0 kernel/bpf/syscall.c:3348
__sys_bpf+0x590/0x7d0 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
x64_sys_call+0x4b9/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:322
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
__kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
insert_work+0x51/0x310 kernel/workqueue.c:1373
__queue_work+0x8e1/0xc60 kernel/workqueue.c:1539
queue_work_on+0xde/0x150 kernel/workqueue.c:1566
queue_work include/linux/workqueue.h:510 [inline]
schedule_work include/linux/workqueue.h:571 [inline]
destroy_super_rcu+0xd1/0xe0 fs/super.c:172
rcu_do_batch+0x4c1/0xbf0 kernel/rcu/tree.c:2523
rcu_core+0x4a3/0xef0 kernel/rcu/tree.c:2763
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2776
handle_softirqs+0x250/0x560 kernel/softirq.c:583
__do_softirq kernel/softirq.c:621 [inline]
invoke_softirq kernel/softirq.c:443 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:670
irq_exit_rcu+0x9/0x10 kernel/softirq.c:682
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:676
Second to last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
__kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
__call_rcu_common kernel/rcu/tree.c:3011 [inline]
call_rcu+0x10b/0xf60 kernel/rcu/tree.c:3129
__put_super+0x26b/0x2d0 fs/super.c:299
put_super fs/super.c:313 [inline]
deactivate_locked_super+0xd4/0x100 fs/super.c:346
deactivate_super+0xaf/0xe0 fs/super.c:366
cleanup_mnt+0x44f/0x500 fs/namespace.c:1149
__cleanup_mnt+0x19/0x20 fs/namespace.c:1156
task_work_run+0x127/0x190 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
The buggy address belongs to the object at ffff888111fbe000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 968 bytes inside of
2048-byte region [ffff888111fbe000, ffff888111fbe800)
The buggy address belongs to the page:
page:ffffea000447ee00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888111fbf000 pfn:0x111fb8
head:ffffea000447ee00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea000441a408 ffffea0004359408 ffff888100043200
raw: ffff888111fbf000 0000000000080001 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 361, ts 30111186003, free_ts 30002771112
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
__alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1937 [inline]
new_slab+0xa0/0x4d0 mm/slub.c:2000
___slab_alloc+0x3ac/0x840 mm/slub.c:3033
__slab_alloc+0x49/0x90 mm/slub.c:3120
slab_alloc_node mm/slub.c:3211 [inline]
slab_alloc mm/slub.c:3255 [inline]
kmem_cache_alloc_trace+0x146/0x270 mm/slub.c:3272
kmalloc include/linux/slab.h:619 [inline]
f2fs_kmalloc fs/f2fs/f2fs.h:3380 [inline]
f2fs_kzalloc fs/f2fs/f2fs.h:3386 [inline]
build_curseg fs/f2fs/segment.c:4529 [inline]
f2fs_build_segment_manager+0x1a08/0x5360 fs/f2fs/segment.c:5277
f2fs_fill_super+0x4576/0x6dd0 fs/f2fs/super.c:4430
mount_bdev+0x28d/0x3c0 fs/super.c:1400
f2fs_mount+0x34/0x40 fs/f2fs/super.c:4713
legacy_get_tree+0xed/0x190 fs/fs_context.c:611
vfs_get_tree+0x89/0x260 fs/super.c:1530
do_new_mount+0x251/0xb40 fs/namespace.c:3037
path_mount+0x640/0xff0 fs/namespace.c:3367
page last free stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
free_pages_prepare mm/page_alloc.c:1474 [inline]
free_pcp_prepare mm/page_alloc.c:1546 [inline]
free_unref_page_prepare+0x5fa/0x600 mm/page_alloc.c:3536
free_unref_page+0xae/0x540 mm/page_alloc.c:3618
free_the_page mm/page_alloc.c:805 [inline]
__free_pages+0x6c/0x100 mm/page_alloc.c:5900
__free_slab+0xe5/0x1e0 mm/slub.c:2025
free_slab mm/slub.c:2040 [inline]
discard_slab mm/slub.c:2046 [inline]
__unfreeze_partials+0x15a/0x190 mm/slub.c:2532
put_cpu_partial+0xc6/0x120 mm/slub.c:2612
__slab_free+0x1d4/0x290 mm/slub.c:3395
do_slab_free mm/slub.c:3514 [inline]
___cache_free+0x104/0x120 mm/slub.c:3535
qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157
qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:443
kasan_slab_alloc include/linux/kasan.h:217 [inline]
slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550
slab_alloc_node mm/slub.c:3245 [inline]
slab_alloc mm/slub.c:3255 [inline]
kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260
getname_flags+0xba/0x510 fs/namei.c:138
user_path_at_empty+0x2f/0x1c0 fs/namei.c:2890
Memory state around the buggy address:
ffff888111fbe280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888111fbe300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888111fbe380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888111fbe400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888111fbe480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
general protection fault, probably for non-canonical address 0xdffffc00000000e9: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000748-0x000000000000074f]
CPU: 0 PID: 1496 Comm: syz.3.272 Tainted: G B syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:f2fs_release_page+0x233/0x7c0 fs/f2fs/data.c:3773
Code: 4d 03 27 4c 89 e0 48 c1 e8 03 42 80 3c 30 00 74 08 4c 89 e7 e8 ae 4b 94 ff 41 bf 48 07 00 00 4d 03 3c 24 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 41 05 00 00 45 8b 3f 44 89 fe 81 e6 00
RSP: 0018:ffffc900010e6d50 EFLAGS: 00010202
RAX: 00000000000000e9 RBX: ffffea0004811640 RCX: 0000000000080000
RDX: ffffc90002b71000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc900010e6d88 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18e4c R12: ffff888111fbe3c8
R13: ffffea0004811648 R14: dffffc0000000000 R15: 0000000000000748
FS: 00007fa3f2ece6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f53da62b000 CR3: 0000000114dfb000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
try_to_release_page+0x18d/0x1e0 mm/filemap.c:4082
shrink_page_list+0x25ff/0x5800 mm/vmscan.c:1793
shrink_inactive_list mm/vmscan.c:2338 [inline]
shrink_list mm/vmscan.c:2583 [inline]
shrink_lruvec+0x1297/0x3a40 mm/vmscan.c:5800
shrink_node_memcgs mm/vmscan.c:5992 [inline]
shrink_node+0x11ee/0x2a40 mm/vmscan.c:6022
shrink_zones mm/vmscan.c:6228 [inline]
do_try_to_free_pages+0x5a7/0x1580 mm/vmscan.c:6286
try_to_free_mem_cgroup_pages+0x261/0x610 mm/vmscan.c:6600
mem_cgroup_force_empty mm/memcontrol.c:3595 [inline]
mem_cgroup_force_empty_write+0x130/0x170 mm/memcontrol.c:3616
cgroup_file_write+0x294/0x560 kernel/cgroup/cgroup.c:4011
kernfs_fop_write_iter+0x2bd/0x400 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2212 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x831/0xfd0 fs/read_write.c:594
ksys_write+0x14a/0x260 fs/read_write.c:647
__do_sys_write fs/read_write.c:659 [inline]
__se_sys_write fs/read_write.c:656 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:656
x64_sys_call+0x8ef/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa3f4475159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa3f2ece028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa3f46fcfa0 RCX: 00007fa3f4475159
RDX: 0000000000000001 RSI: 00002000000002c0 RDI: 0000000000000007
RBP: 00007fa3f450c03b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa3f46fd038 R14: 00007fa3f46fcfa0 R15: 00007ffde92694b8
</TASK>
Modules linked in:
---[ end trace f33208ea756797c5 ]---
RIP: 0010:f2fs_release_page+0x233/0x7c0 fs/f2fs/data.c:3773
Code: 4d 03 27 4c 89 e0 48 c1 e8 03 42 80 3c 30 00 74 08 4c 89 e7 e8 ae 4b 94 ff 41 bf 48 07 00 00 4d 03 3c 24 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 41 05 00 00 45 8b 3f 44 89 fe 81 e6 00
RSP: 0018:ffffc900010e6d50 EFLAGS: 00010202
RAX: 00000000000000e9 RBX: ffffea0004811640 RCX: 0000000000080000
RDX: ffffc90002b71000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc900010e6d88 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18e4c R12: ffff888111fbe3c8
R13: ffffea0004811648 R14: dffffc0000000000 R15: 0000000000000748
FS: 00007fa3f2ece6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa3f44c2840 CR3: 0000000114dfb000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 4d 03 27 add (%r15),%r12
3: 4c 89 e0 mov %r12,%rax
6: 48 c1 e8 03 shr $0x3,%rax
a: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)
f: 74 08 je 0x19
11: 4c 89 e7 mov %r12,%rdi
14: e8 ae 4b 94 ff call 0xff944bc7
19: 41 bf 48 07 00 00 mov $0x748,%r15d
1f: 4d 03 3c 24 add (%r12),%r15
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 0f 85 41 05 00 00 jne 0x578
37: 45 8b 3f mov (%r15),%r15d
3a: 44 89 fe mov %r15d,%esi
3d: 81 .byte 0x81
3e: e6 00 out %al,$0x0
Struck through repros no longer work on HEAD.