BUG: unable to handle kernel paging request in ioat_pci_probe

Status: upstream: reported syz repro on 2026/08/22 03:40
Subsystems: dmaengine
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+79a6b3f7a8df01f58774@syzkaller.appspotmail.com
First crash: 10d, last: 7d15h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
d7fee4e9 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ BUG: unable to handle kernel paging request in ioat_pci_probe 2026/08/19 03:23 2026/08/19 03:23 2026/08/19 04:11 1e72964b
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [dmaengine?] BUG: unable to handle kernel paging request in ioat_pci_probe 1 (2) 2026/08/24 16:02
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 BUG: unable to handle kernel paging request in ioat_pci_probe 8 syz, C 2 9d04h 11d 0/3 upstream: reported C repro on 2026/08/17 18:55

Sample crash report:
BUG: unable to handle page fault for address: 000000000001c0a8
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 5523b067 P4D 5523b067 PUD 4c5b0067 PMD 0 
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5910 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:readb arch/x86/include/asm/io.h:57 [inline]
RIP: 0010:ioat_pci_probe+0x169/0x2880 drivers/dma/ioat/init.c:1365
Code: 4d 2f d3 ff 48 89 c3 48 85 c0 0f 84 de 1f 00 00 e8 cc 50 7c fc 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 ec 25 00 00 48 8b 03 <44> 8a 68 08 bf 2f 00 00 00 44 89 ee e8 b6 4a 7c fc 41 80 fd 2f 0f
RSP: 0018:ffffc90002daf7c8 EFLAGS: 00010246
RAX: 000000000001c0a0 RBX: ffff888028961238 RCX: 0000000000000000
RDX: ffff888029bc8000 RSI: ffffffff858deac4 RDI: 0000000000000001
RBP: ffff888021572000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff858de970 R15: ffff888021572130
FS:  0000000000000000(0000) GS:ffff8880969bd000(0063) knlGS:00000000571be480
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000000001c0a8 CR3: 0000000055268000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 local_pci_probe+0xdd/0x1b0 drivers/pci/pci-driver.c:332
 pci_call_probe+0x176/0x800 drivers/pci/pci-driver.c:394
 __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
 pci_device_probe+0x1cd/0x370 drivers/pci/pci-driver.c:489
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
 device_driver_attach+0xd1/0x220 drivers/base/dd.c:1203
 bind_store+0xf4/0x190 drivers/base/bus.c:267
 drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf709efec
Code: Unable to access opcode bytes at 0xf709efc2.
RSP: 002b:00000000ff94267c EFLAGS: 00000292 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000080000600
RDX: 000000000000000d RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
CR2: 000000000001c0a8
---[ end trace 0000000000000000 ]---
RIP: 0010:readb arch/x86/include/asm/io.h:57 [inline]
RIP: 0010:ioat_pci_probe+0x169/0x2880 drivers/dma/ioat/init.c:1365
Code: 4d 2f d3 ff 48 89 c3 48 85 c0 0f 84 de 1f 00 00 e8 cc 50 7c fc 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 ec 25 00 00 48 8b 03 <44> 8a 68 08 bf 2f 00 00 00 44 89 ee e8 b6 4a 7c fc 41 80 fd 2f 0f
RSP: 0018:ffffc90002daf7c8 EFLAGS: 00010246
RAX: 000000000001c0a0 RBX: ffff888028961238 RCX: 0000000000000000
RDX: ffff888029bc8000 RSI: ffffffff858deac4 RDI: 0000000000000001
RBP: ffff888021572000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff858de970 R15: ffff888021572130
FS:  0000000000000000(0000) GS:ffff8880969bd000(0063) knlGS:00000000571be480
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f709f000 CR3: 0000000055268000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	4d 2f                	rex.WRB (bad)
   2:	d3 ff                	sar    %cl,%edi
   4:	48 89 c3             	mov    %rax,%rbx
   7:	48 85 c0             	test   %rax,%rax
   a:	0f 84 de 1f 00 00    	je     0x1fee
  10:	e8 cc 50 7c fc       	call   0xfc7c50e1
  15:	48 89 d8             	mov    %rbx,%rax
  18:	48 c1 e8 03          	shr    $0x3,%rax
  1c:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  21:	0f 85 ec 25 00 00    	jne    0x2613
  27:	48 8b 03             	mov    (%rbx),%rax
* 2a:	44 8a 68 08          	mov    0x8(%rax),%r13b <-- trapping instruction
  2e:	bf 2f 00 00 00       	mov    $0x2f,%edi
  33:	44 89 ee             	mov    %r13d,%esi
  36:	e8 b6 4a 7c fc       	call   0xfc7c4af1
  3b:	41 80 fd 2f          	cmp    $0x2f,%r13b
  3f:	0f                   	.byte 0xf

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/21 04:49 upstream 9d2ed026f031 1e72964b .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 BUG: unable to handle kernel paging request in ioat_pci_probe
2026/08/18 18:38 linux-next e6664f2b33db 1e72964b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce BUG: unable to handle kernel paging request in ioat_pci_probe
2026/08/18 03:30 linux-next 4477a78374a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce BUG: unable to handle kernel paging request in ioat_pci_probe
* Struck through repros no longer work on HEAD.