syzbot
BUG: unable to handle kernel paging request in read_seqbegin
Status:
moderation: reported on 2026/10/11 00:03
Subsystems:
fs
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+1e42cd1776f072f51137@syzkaller.appspotmail.com
First crash: 4d16h, last: 4d16h
Sample crash report:
Unable to handle kernel paging request at virtual address dfff800000000002
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
Mem abort info:
ESR = 0x0000000096000005
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x05: level 1 translation fault
Data abort info:
ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0
[dfff800000000002] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1] SMP
Modules linked in:
CPU: 1 UID: 0 PID: 7658 Comm: syz.0.640 Tainted: G L syzkaller #0 PREEMPT
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
pstate: 834000c5 (Nzcv daIF +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : kasan_byte_accessible+0xc/0x1c mm/kasan/generic.c:210
lr : __kasan_check_byte+0x20/0x54 mm/kasan/common.c:573
sp : ffff8000929e6920
x29: ffff8000929e6920 x28: ffff800088a7a000 x27: ffff0000f085d880
x26: b488800080d7b14c x25: 0000000000000000 x24: 0000000000000001
x23: 0000000000000002 x22: 0000000000000010 x21: 0000000000000010
x20: 0000000000000000 x19: ffff800080d7b14c x18: ffff8001254aa000
x17: ffff800080300f14 x16: ffff8000803704a8 x15: ffff800080302e70
x14: 0000000000b7fef0 x13: 0000000000000009 x12: 0000000000000009
x11: ffff800080155708 x10: 0000000000000003 x9 : dfff800000000000
x8 : 0000000000000002 x7 : 0000000000000000 x6 : ffff800080d79dac
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000002
x2 : 0000000000000000 x1 : ffff800080d7b14c x0 : 0000000000000010
Call trace:
kasan_mem_to_shadow include/linux/kasan.h:65 [inline] (P)
kasan_byte_accessible+0xc/0x1c mm/kasan/generic.c:210 (P)
kasan_check_byte include/linux/kasan.h:402 [inline]
lock_acquire+0xa4/0x320 kernel/locking/lockdep.c:5916
seqcount_lockdep_reader_access include/linux/seqlock.h:73 [inline]
read_seqbegin+0x6c/0x144 include/linux/seqlock.h:838
get_fs_root_rcu fs/d_path.c:244 [inline]
d_path+0x224/0x4dc fs/d_path.c:287
audit_log_d_path+0xdc/0x19c kernel/audit.c:2221
audit_log_lsm_data+0xe0/0x12d0 security/lsm_audit.c:199
dump_common_audit_data security/lsm_audit.c:421 [inline]
common_lsm_audit+0x1d0/0x290 security/lsm_audit.c:451
smack_log+0x1f4/0x264 security/smack/smack_access.c:400
smk_tskacc+0x210/0x2ac security/smack/smack_access.c:255
smack_file_open+0x1d0/0x230 security/smack/smack_lsm.c:2078
security_file_open+0xec/0x258 security/security.c:2739
do_dentry_open+0x2a8/0xfbc fs/open.c:973
vfs_open+0x44/0x2dc fs/open.c:1101
dentry_open+0x74/0xc0 fs/open.c:1124
ima_calc_file_hash+0x120/0x5cc security/integrity/ima/ima_crypto.c:269
ima_collect_measurement+0x420/0x874 security/integrity/ima/ima_api.c:300
ima_update_xattr+0x160/0x230 security/integrity/ima/ima_appraise.c:617
ima_check_last_writer security/integrity/ima/ima_main.c:227 [inline]
ima_file_free+0x40c/0x528 security/integrity/ima/ima_main.c:251
security_file_release+0x84/0x148 security/security.c:2424
__fput+0x2c4/0x74c fs/file_table.c:506
____fput+0x20/0x30 fs/file_table.c:540
task_work_run+0x1cc/0x25c kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x58c/0x1a74 kernel/exit.c:986
do_group_exit+0x198/0x238 kernel/exit.c:1129
get_signal+0xfb0/0x1094 kernel/signal.c:3112
arch_do_signal_or_restart+0x1c8/0x444c arch/arm64/kernel/signal.c:1671
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x70/0x17c kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
arm64_exit_to_user_mode arch/arm64/kernel/entry-common.c:161 [inline]
el0_da+0x14c/0x1d4 arch/arm64/kernel/entry-common.c:613
el0t_64_sync_handler+0xd8/0x104 arch/arm64/kernel/entry-common.c:818
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606
Code: 17ffffec d343fc08 d2d00009 f2fbffe9 (38696908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 17ffffec b 0xffffffffffffffb0
4: d343fc08 lsr x8, x0, #3
8: d2d00009 mov x9, #0x800000000000 // #140737488355328
c: f2fbffe9 movk x9, #0xdfff, lsl #48
* 10: 38696908 ldrb w8, [x8, x9] <-- trapping instruction
* Struck through repros no longer work on HEAD.