* [syzbot] [dmaengine?] BUG: unable to handle kernel paging request in ioat_pci_probe
@ 2026-08-22 3:40 syzbot
2026-08-24 16:02 ` Dave Jiang
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2026-08-22 3:40 UTC (permalink / raw)
To: Frank.Li, dmaengine, linux-kernel, syzkaller-bugs, vkoul
Hello,
syzbot found the following issue on:
HEAD commit: 9d2ed026f031 Merge tag 'sysctl-7.03-rc1' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11837a25580000
kernel config: https://syzkaller.appspot.com/x/.config?x=54b748b029440e0b
dashboard link: https://syzkaller.appspot.com/bug?extid=79a6b3f7a8df01f58774
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10830415580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-9d2ed026.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6c5c2e657d2b/vmlinux-9d2ed026.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4d4c9e33af49/bzImage-9d2ed026.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+79a6b3f7a8df01f58774@syzkaller.appspotmail.com
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
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [dmaengine?] BUG: unable to handle kernel paging request in ioat_pci_probe
2026-08-22 3:40 [syzbot] [dmaengine?] BUG: unable to handle kernel paging request in ioat_pci_probe syzbot
@ 2026-08-24 16:02 ` Dave Jiang
0 siblings, 0 replies; 2+ messages in thread
From: Dave Jiang @ 2026-08-24 16:02 UTC (permalink / raw)
To: syzbot, Frank.Li, dmaengine, linux-kernel, syzkaller-bugs, vkoul
On 8/21/26 8:40 PM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 9d2ed026f031 Merge tag 'sysctl-7.03-rc1' of git://git.kern..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11837a25580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=54b748b029440e0b
> dashboard link: https://syzkaller.appspot.com/bug?extid=79a6b3f7a8df01f58774
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> userspace arch: i386
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10830415580000
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-9d2ed026.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/6c5c2e657d2b/vmlinux-9d2ed026.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/4d4c9e33af49/bzImage-9d2ed026.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+79a6b3f7a8df01f58774@syzkaller.appspotmail.com
This is not a real bug. In order to reproduce, the attacker must already have root access. And it needs to force bind the ioatdma driver to an arbitrary device that has I/O port as BAR0 instead of MMIO. While we can add a check in the driver to block that, I don't think it's necessary at this point.
DJ
>
> 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
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-08-24 16:02 UTC | newest]
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2026-08-22 3:40 [syzbot] [dmaengine?] BUG: unable to handle kernel paging request in ioat_pci_probe syzbot
2026-08-24 16:02 ` Dave Jiang
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