syzbot
BUG: unable to handle kernel NULL pointer dereference in getname_kernel
Status:
upstream: reported C repro on 2026/09/08 01:21
Subsystems:
fs
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+6c46a179b56c651c4c96@syzkaller.appspotmail.com
First crash: 1d05h, last: 12h45m
Sample crash report:
nvmet: adding nsid 1 to subsystem testsubsys
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0
user pgtable: 4k pages, 52-bit VAs, pgdp=00000000437b3a80
[0000000000000000] pgd=0800000053c32403, p4d=0800000053721403, pud=0800000049146403, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] SMP
Modules linked in:
CPU: 1 UID: 0 PID: 3633 Comm: syz.2.17 Tainted: G W syzkaller #0 PREEMPT
Tainted: [W]=WARN
Hardware name: linux,dummy-virt (DT)
pstate: 61402009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : __pi_strlen+0x14/0x150 arch/arm64/lib/strlen.S:87
lr : __fortify_strlen include/linux/fortify-string.h:218 [inline]
lr : do_getname_kernel+0x20/0x12c fs/namei.c:260
sp : ffff800089c2bb60
x29: ffff800089c2bb60 x28: fbf0000003fa8000 x27: 0000000000000000
x26: 0000000000000000 x25: 0000000000000000 x24: fcf0000008b7db00
x23: f3f00000067df000 x22: 0000000000000000 x21: 0000000000000000
x20: 00000000fffffff1 x19: 0000000000020002 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 00000000200004c0
x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000078
x8 : 0101010101010101 x7 : fcf0000008b7db08 x6 : fdf0000013703002
x5 : fdf0000013703002 x4 : 0000000000000000 x3 : fbf0000003fa8000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
__pi_strlen+0x14/0x150 arch/arm64/lib/strlen.S:86 (P)
getname_kernel+0x14/0x20 fs/namei.c:289
class_filename_kernel_constructor include/linux/fs.h:2586 [inline]
filp_open+0x34/0x104 fs/open.c:1391
nvmet_file_ns_enable+0x38/0xfc drivers/nvme/target/io-cmd-file.c:41
nvmet_ns_enable+0x12c/0x1e0 drivers/nvme/target/core.c:596
nvmet_ns_enable_store+0x64/0xd4 drivers/nvme/target/configfs.c:737
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0xc4/0x128 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x244/0x36c fs/read_write.c:687
ksys_write+0x70/0x108 fs/read_write.c:739
__do_sys_write fs/read_write.c:750 [inline]
__se_sys_write fs/read_write.c:747 [inline]
__arm64_sys_write+0x18/0x24 fs/read_write.c:747
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x54/0x10c arch/arm64/kernel/syscall.c:49
el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:121
do_el0_svc+0x1c/0x34 arch/arm64/kernel/syscall.c:140
el0_svc+0x38/0x1fc arch/arm64/kernel/entry-common.c:758
el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:777
el0t_64_sync+0x1a4/0x1a8 arch/arm64/kernel/entry.S:590
Code: 92400c04 b200c3e8 f100009f 5400088c (a9400c02)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 92400c04 and x4, x0, #0xf
4: b200c3e8 mov x8, #0x101010101010101 // #72340172838076673
8: f100009f cmp x4, #0x0
c: 5400088c b.gt 0x11c
* 10: a9400c02 ldp x2, x3, [x0] <-- trapping instruction
* Struck through repros no longer work on HEAD.