syzbot


BUG: unable to handle kernel NULL pointer dereference in destroy_ai

Status: moderation: reported on 2026/06/13 22:08
Subsystems: mtd
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+08e9eb39f7bc678a0769@syzkaller.appspotmail.com
First crash: 4d07h, last: 4d07h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
f3b8d778-ad08-49d4-b3f9-379e5c1585fa assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ BUG: unable to handle kernel NULL pointer dereference in destroy_ai 2026/06/11 00:26 2026/06/11 00:26 2026/06/11 01:04 416ea548b956322d21a679fe8e300a65581814ce

Sample crash report:
ubi0 error: ubi_read_volume_table: the layout volume was not found
BUG: kernel NULL pointer dereference, address: 0000000000000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0001) - permissions violation
PGD 8000000059dbe067 P4D 8000000059dbe067 PUD 6aba4067 PMD 6282d067 PTE 800000007da12067
Oops: Oops: 0001 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 8974 Comm: syz.5.499 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:qlink_to_cache mm/kasan/quarantine.c:131 [inline]
RIP: 0010:qlist_move_cache+0x9d/0xf0 mm/kasan/quarantine.c:303
Code: 48 89 c2 48 c1 e2 06 48 03 15 5f 12 a7 0b 48 8b 42 08 48 89 c1 83 e1 01 48 83 e9 01 48 09 c8 48 21 d0 80 78 33 f5 49 0f 45 c4 <48> 8b 40 08 8b 50 18 48 39 c5 75 92 48 83 3b 00 74 33 48 8b 43 08
RSP: 0018:ffffc90003d97a38 EFLAGS: 00010006
RAX: 0000000000000000 RBX: ffffc90003d97a70 RCX: ffffffffffffffff
RDX: ffffea0001e07400 RSI: ffffc90003d97a70 RDI: ffff8880781d0001
RBP: ffff88807bb36140 R08: 0000000000000001 R09: fffff520007b2f3c
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff9b1b6d60 R14: ffff8880781d0001 R15: 0000000000000000
FS:  00007fb56d4876c0(0000) GS:ffff88812438e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000043eec000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 kasan_quarantine_remove_cache+0xf7/0x170 mm/kasan/quarantine.c:370
 kmem_cache_destroy mm/slab_common.c:567 [inline]
 kmem_cache_destroy+0x6b/0x190 mm/slab_common.c:527
 destroy_ai+0x896/0xda0 drivers/mtd/ubi/attach.c:1360
 ubi_attach+0xa00/0x4d30 drivers/mtd/ubi/attach.c:1648
 ubi_attach_mtd_dev+0x139f/0x32a0 drivers/mtd/ubi/build.c:1004
 ctrl_cdev_ioctl+0x36a/0x400 drivers/mtd/ubi/cdev.c:1113
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb56c59ce59
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:00007fb56d487028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb56c816180 RCX: 00007fb56c59ce59
RDX: 0000000000000000 RSI: 0000000040186f40 RDI: 0000000000000005
RBP: 00007fb56c632d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb56c816218 R14: 00007fb56c816180 R15: 00007ffd9a2e6d98
 </TASK>
Modules linked in:
CR2: 0000000000000008
---[ end trace 0000000000000000 ]---
RIP: 0010:qlink_to_cache mm/kasan/quarantine.c:131 [inline]
RIP: 0010:qlist_move_cache+0x9d/0xf0 mm/kasan/quarantine.c:303
Code: 48 89 c2 48 c1 e2 06 48 03 15 5f 12 a7 0b 48 8b 42 08 48 89 c1 83 e1 01 48 83 e9 01 48 09 c8 48 21 d0 80 78 33 f5 49 0f 45 c4 <48> 8b 40 08 8b 50 18 48 39 c5 75 92 48 83 3b 00 74 33 48 8b 43 08
RSP: 0018:ffffc90003d97a38 EFLAGS: 00010006
RAX: 0000000000000000 RBX: ffffc90003d97a70 RCX: ffffffffffffffff
RDX: ffffea0001e07400 RSI: ffffc90003d97a70 RDI: ffff8880781d0001
RBP: ffff88807bb36140 R08: 0000000000000001 R09: fffff520007b2f3c
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff9b1b6d60 R14: ffff8880781d0001 R15: 0000000000000000
FS:  00007fb56d4876c0(0000) GS:ffff88812438e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000043eec000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	48 89 c2             	mov    %rax,%rdx
   3:	48 c1 e2 06          	shl    $0x6,%rdx
   7:	48 03 15 5f 12 a7 0b 	add    0xba7125f(%rip),%rdx        # 0xba7126d
   e:	48 8b 42 08          	mov    0x8(%rdx),%rax
  12:	48 89 c1             	mov    %rax,%rcx
  15:	83 e1 01             	and    $0x1,%ecx
  18:	48 83 e9 01          	sub    $0x1,%rcx
  1c:	48 09 c8             	or     %rcx,%rax
  1f:	48 21 d0             	and    %rdx,%rax
  22:	80 78 33 f5          	cmpb   $0xf5,0x33(%rax)
  26:	49 0f 45 c4          	cmovne %r12,%rax
* 2a:	48 8b 40 08          	mov    0x8(%rax),%rax <-- trapping instruction
  2e:	8b 50 18             	mov    0x18(%rax),%edx
  31:	48 39 c5             	cmp    %rax,%rbp
  34:	75 92                	jne    0xffffffc8
  36:	48 83 3b 00          	cmpq   $0x0,(%rbx)
  3a:	74 33                	je     0x6f
  3c:	48 8b 43 08          	mov    0x8(%rbx),%rax

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/09 22:05 upstream 2d3090a8aeb5 c36c07f6 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel NULL pointer dereference in destroy_ai
* Struck through repros no longer work on HEAD.