From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 29EED43F08D; Mon, 24 Aug 2026 16:02:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787587327; cv=none; b=qlDIeqK5qitmg76r7iSh0MBh54/MRPFY8o0ELq7A9yUSQRXYqR6FN0I3Km2W0SY0X/n4Bf0p6iuncNADqbzQQjSd/bhmgQl7WHOAWYqL8bKZGzFhiptOpr87RXrV9meEBzDhiKj/XjK6hdVfxBSZI7sL/tD/C/N4kt2dsEMnxyQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787587327; c=relaxed/simple; bh=ny50pXao9+hiGG++uQ0lPNnCHDvOpt/UHG7/er4/oWQ=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=ja8mKikFAkKeId+spOZ1z3kqfiZTCd1uWLZFq+dZQh+JkATQpKD5cYKexn+BJ2j43BHYF4mdbtZrQPGxgCSzsUI5sYo1UKPFZ/DvhTvgwA7S9eBVc+AMMfbmVdfHa9wwmuq3pOFEaytISDX3wVRYapwxknfWWB0RUols1DzOUgw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Uq54yAxD; arc=none smtp.client-ip=192.198.163.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Uq54yAxD" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1787587326; x=1819123326; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=ny50pXao9+hiGG++uQ0lPNnCHDvOpt/UHG7/er4/oWQ=; b=Uq54yAxDioxrDAhvll+fbo/hhKamVzIRJdG293sIY0l+q3UK/uYwriYp 1sqEQXuo0oN4NQLMBcE1bTeMyrH5sxOvBpfZBWQdGmTlOtwANVI8o3YEV WdNFyN2vbDjytc7w0jJRNCUJon/sG79UMl9IOgz/6PE0AxKxRnXg22h4R XEXSumJwSbWpDc1EYNNDkmYjhbrDybzk1azZdA9b2dm/jRUv/2AIvAGdP UjRVDPUEmIug6/hESnZ11e5gtdHfijpvF6Hi2bNjU66MIKZnqvxJ8vfx+ Px0JT8c26RW27AyKTUNILgyIyjKrWPtMBNrmHlYWh7f+Lui7TMNTUQ/lF A==; X-CSE-ConnectionGUID: e9UQudY2Scy2HA/EoVlTwQ== X-CSE-MsgGUID: DyXDZYALQe+wiT/kPAzhxQ== X-IronPort-AV: E=McAfee;i="6800,10657,11885"; a="86994274" X-IronPort-AV: E=Sophos;i="6.25,240,1779174000"; d="scan'208";a="86994274" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2026 09:02:05 -0700 X-CSE-ConnectionGUID: +dBJa4oMS/qcDBX3IUxexA== X-CSE-MsgGUID: 5OP7oru7T+m6mHF/l93yiA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,240,1779174000"; d="scan'208";a="263766776" Received: from jjgreens-desk24.amr.corp.intel.com (HELO [10.125.108.201]) ([10.125.108.201]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2026 09:02:04 -0700 Message-ID: Date: Mon, 24 Aug 2026 09:02:02 -0700 Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [dmaengine?] BUG: unable to handle kernel paging request in ioat_pci_probe To: syzbot , Frank.Li@kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, vkoul@kernel.org References: <6a891a2c.91706f20.16b6e3.02b1.GAE@google.com> From: Dave Jiang Content-Language: en-US In-Reply-To: <6a891a2c.91706f20.16b6e3.02b1.GAE@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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: > > 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 > > 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 >