syzbot
BUG: unable to handle kernel NULL pointer dereference in d_path
Status:
moderation: reported on 2026/10/09 04:12
Subsystems:
fs
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+bc636a591b56e90c201e@syzkaller.appspotmail.com
First crash: 4d10h, last: 4d10h
Sample crash report:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0
user pgtable: 4k pages, 52-bit VAs, pgdp=0000000046307b00
[0000000000000004] pgd=080000004673d403, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] SMP
Modules linked in:
CPU: 1 UID: 0 PID: 29486 Comm: syz.3.8345 Tainted: G L syzkaller #0 PREEMPT
Tainted: [L]=SOFTLOCKUP
Hardware name: linux,dummy-virt (DT)
pstate: 61402009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : __seqprop_spinlock_sequence include/linux/seqlock.h:228 [inline]
pc : read_seqbegin include/linux/seqlock.h:838 [inline]
pc : get_fs_root_rcu fs/d_path.c:244 [inline]
pc : d_path+0xcc/0x1b0 fs/d_path.c:287
lr : rcu_read_lock include/linux/rcupdate.h:847 [inline]
lr : d_path+0xc0/0x1b0 fs/d_path.c:286
sp : ffff80008a473690
x29: ffff80008a4736c0 x28: fbf000000645ee68 x27: 00000000000002e2
x26: f8f000000b21f338 x25: 0000000000000000 x24: f8f000000b21f338
x23: ffff800082cc03b8 x22: 0000000000000000 x21: ffff80008a473850
x20: fcf00000404ec000 x19: 000000000000100b x18: 00000000ffffffff
x17: 0000000000000000 x16: 0000000000000000 x15: fcf0000009d0987c
x14: ffffffffffffffff x13: 0000000000000010 x12: 0101010101010101
x11: 7f7f7f7f7f7f7f7f x10: fefefefefeff3433 x9 : 0000000000000000
x8 : 00000000ffff8000 x7 : dead000000000122 x6 : fbf000000645e600
x5 : 0000000000000001 x4 : 0000000000003520 x3 : fbf000000645e600
x2 : 0000000000000004 x1 : fbf000000645e600 x0 : 0000000000000000
Call trace:
get_fs_root_rcu fs/d_path.c:241 [inline] (P)
d_path+0xcc/0x1b0 fs/d_path.c:287 (P)
audit_log_d_path+0x80/0xec kernel/audit.c:2221
audit_log_lsm_data+0x118/0x7dc security/lsm_audit.c:199
dump_common_audit_data security/lsm_audit.c:421 [inline]
common_lsm_audit+0xf0/0x180 security/lsm_audit.c:451
smack_log+0x88/0xd4 security/smack/smack_access.c:400
smk_tskacc+0x80/0x10c security/smack/smack_access.c:255
smack_file_open+0x98/0xcc security/smack/smack_lsm.c:2078
security_file_open+0x90/0x148 security/security.c:2739
do_dentry_open+0xe0/0x4fc fs/open.c:973
vfs_open+0x2c/0xe8 fs/open.c:1101
dentry_open+0x40/0x80 fs/open.c:1124
ima_calc_file_hash+0x40/0x120 security/integrity/ima/ima_crypto.c:269
ima_collect_measurement+0x2d0/0x30c security/integrity/ima/ima_api.c:300
ima_update_xattr+0x6c/0xb0 security/integrity/ima/ima_appraise.c:617
ima_check_last_writer security/integrity/ima/ima_main.c:227 [inline]
ima_file_free+0xe4/0x154 security/integrity/ima/ima_main.c:251
security_file_release+0xb0/0x120 security/security.c:2424
__fput+0xac/0x2f8 fs/file_table.c:506
____fput+0x14/0x20 fs/file_table.c:540
task_work_run+0x70/0xe0 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x26c/0x940 kernel/exit.c:986
do_group_exit+0x34/0x9c kernel/exit.c:1129
get_signal+0x7a0/0x864 kernel/signal.c:3112
arch_do_signal_or_restart+0x11c/0x3dc arch/arm64/kernel/signal.c:1671
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x114/0x19c 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:123 [inline]
el0_da+0xe8/0xf0 arch/arm64/kernel/entry-common.c:575
el0t_64_sync_handler+0xd0/0xe4 arch/arm64/kernel/entry-common.c:780
el0t_64_sync+0x1a4/0x1a8 arch/arm64/kernel/entry.S:590
Code: 97f50eed d5384100 f9440c00 91001002 (88dffc41)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 97f50eed bl 0xffffffffffd43bb4
4: d5384100 mrs x0, sp_el0
8: f9440c00 ldr x0, [x0, #2072]
c: 91001002 add x2, x0, #0x4
* 10: 88dffc41 ldar w1, [x2] <-- trapping instruction
* Struck through repros no longer work on HEAD.