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[2403:580d:fda1::299]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c4cbfc2f476sm7028868a12.8.2026.01.13.15.03.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 13 Jan 2026 15:03:28 -0800 (PST) Message-ID: <5a643fd6-1b1c-45ad-86a0-5d53f074d6f7@suse.com> Date: Wed, 14 Jan 2026 09:33:23 +1030 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [REGRESSION] VirtualBox VM crashes (BSOD) during Windows installation on btrfs with kernels 6.18+ (works on 6.12 LTS) To: jollycar , Qu Wenruo Cc: "regressions@lists.linux.dev" , "linux-btrfs@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <5b466d2f-80ad-4b45-a643-ab64bf2b252d@suse.com> <20c3ba51-fbf1-4de2-b88f-5edf817a24d6@suse.com> <07600bff-a6dc-4b86-9dd6-aa5077ca8b09@suse.com> Content-Language: en-US From: Qu Wenruo Autocrypt: addr=wqu@suse.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNGFF1IFdlbnJ1byA8d3F1QHN1c2UuY29tPsLAlAQTAQgAPgIbAwULCQgHAgYVCAkKCwIE FgIDAQIeAQIXgBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJnEXVgBQkQ/lqxAAoJEMI9kfOh Jf6o+jIH/2KhFmyOw4XWAYbnnijuYqb/obGae8HhcJO2KIGcxbsinK+KQFTSZnkFxnbsQ+VY fvtWBHGt8WfHcNmfjdejmy9si2jyy8smQV2jiB60a8iqQXGmsrkuR+AM2V360oEbMF3gVvim 2VSX2IiW9KERuhifjseNV1HLk0SHw5NnXiWh1THTqtvFFY+CwnLN2GqiMaSLF6gATW05/sEd V17MdI1z4+WSk7D57FlLjp50F3ow2WJtXwG8yG8d6S40dytZpH9iFuk12Sbg7lrtQxPPOIEU rpmZLfCNJJoZj603613w/M8EiZw6MohzikTWcFc55RLYJPBWQ+9puZtx1DopW2jOwE0EWdWB rwEIAKpT62HgSzL9zwGe+WIUCMB+nOEjXAfvoUPUwk+YCEDcOdfkkM5FyBoJs8TCEuPXGXBO Cl5P5B8OYYnkHkGWutAVlUTV8KESOIm/KJIA7jJA+Ss9VhMjtePfgWexw+P8itFRSRrrwyUf E+0WcAevblUi45LjWWZgpg3A80tHP0iToOZ5MbdYk7YFBE29cDSleskfV80ZKxFv6koQocq0 vXzTfHvXNDELAuH7Ms/WJcdUzmPyBf3Oq6mKBBH8J6XZc9LjjNZwNbyvsHSrV5bgmu/THX2n g/3be+iqf6OggCiy3I1NSMJ5KtR0q2H2Nx2Vqb1fYPOID8McMV9Ll6rh8S8AEQEAAcLAfAQY AQgAJgIbDBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJnEXWBBQkQ/lrSAAoJEMI9kfOhJf6o cakH+QHwDszsoYvmrNq36MFGgvAHRjdlrHRBa4A1V1kzd4kOUokongcrOOgHY9yfglcvZqlJ qfa4l+1oxs1BvCi29psteQTtw+memmcGruKi+YHD7793zNCMtAtYidDmQ2pWaLfqSaryjlzR /3tBWMyvIeWZKURnZbBzWRREB7iWxEbZ014B3gICqZPDRwwitHpH8Om3eZr7ygZck6bBa4MU o1XgbZcspyCGqu1xF/bMAY2iCDcq6ULKQceuKkbeQ8qxvt9hVxJC2W3lHq8dlK1pkHPDg9wO JoAXek8MF37R8gpLoGWl41FIUb3hFiu3zhDDvslYM4BmzI18QgQTQnotJH8= In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2026/1/14 05:38, jollycar 写道: > Thanks for the response. > > Module installation: DKMS via the virtualbox-host-dkms package. The dkms status output confirms vboxhost/7.2.4_OSE is compiled for each kernel including the broken ones (6.18.3, 6.18.5 (tkg), 6.19.0-rc3). > > Regarding CPU type specification: > > VirtualBox doesn't have qemu-style CPU model selection. The --cpu-profile option only supports "host" (full passthrough) or ancient CPUs (8086/80286/80386) which don't meet Windows 10 requirements. > > Additional testing: I recently upgraded my desktop pc from Ryzen 9 5900X to 9950X3D (reusing same disks and linux install) and the regression occurred identically on both CPUs. Also tested custom compiled TKG kernels (6.12/6.18 with bore scheduler). The behavior matches the Manjaro kernels exactly (6.12 works, 6.18 breaks). Thanks for the extra info, I guess the last thing we can verify is, try to run the same VBox setup, using disk images from an EXT4/XFS. And if that still failed, we're sure it's fs independent but more likely VBox dependent. Thanks, Qu > > Regards, > Jollycar > > On Monday, January 12th, 2026 at 8:48 PM, Qu Wenruo wrote: > >> >> >> >> >> 在 2026/1/13 02:03, jollycar 写道: >> >>> Qemu/libvirt test results on kernel 6.18.3: >>> >>> Setup: >>> - Virtualization: qemu via libvirt (virt-manager) >>> - Disk format: qcow2 >>> - Disk location: /data/virtual-os/win10-qemu-test.qcow2 (same btrfs subvolume as VirtualBox VMs) >>> - COW disabled on disk image (chattr +C) >>> - ISO: Same Windows 10 ISO used in VirtualBox tests >>> - Guest: Windows 10 >>> >>> Result: >>> Windows 10 installation completed successfully without any crashes. Installation proceeded through all phases including multiple reboots and reached the desktop without issues. >>> >>> Summary of all tests on kernel 6.18.3: >>> - VirtualBox 7.2.4: Crashes during installation (all cache/mtype configurations tested) >>> - Qemu via libvirt: No crashes, installation completes successfully >>> >>> Both using the same btrfs filesystem, same subvolume location, same Windows ISO, and COW disabled. >> >> >> Thanks a lot, this looks like there is something wrong related to the >> VBox out-of-tree kernel module. >> In that case, the btrfs community is not going to help much unfortunately. >> >> Mind to share how is the out-of-tree kernel module installed? >> The pre-compiled one from the distro? The DKMS one or something else? >> >> >> And just some guesses, can VBox specify what type of CPU (and extensions >> like SSE/AVX) it uses? >> If so (like qemu), mind to check if you can specify some CPU types >> without some newer extensions while still meets the minimal CPU >> requirement of Windows 10? >> >> I'm wondering if it's some extension handling not done properly, which >> is commonly utilized by checksums. >> Thus triggers the checksum mismatch errors inside Windows. >> >> Thanks, >> Qu >> >> >>> On Sunday, January 11th, 2026 at 8:43 PM, Qu Wenruo wqu@suse.com wrote: >>> >>>> 在 2026/1/11 21:39, jollycar 写道: >>>> >>>>> Storage configuration details: >>>>> >>>>> Storage format: VDI (VirtualBox Disk Image) >>>>> Storage location: /data/virtual-os/ (btrfs subvolume with COW disabled, verified with lsattr) >>>> >>>> OK, this means it's not related to the direct IO changes in newer kernels. >>>> >>>> When COW is disabled, data checksum is also disables, thus direct IO is >>>> still doing the true zero-copy behavior. >>>> >>>> This ruled out the btrfs direct io change, but this means I have no clue >>>> what is going wrong at all now. >>>> >>>>> Controller: IntelAhci (SATA) >>>>> Default configuration: hostiocache on, mtype normal >>>>> >>>>> Cache and media type testing on kernel 6.18.3: >>>>> - Default (hostiocache on, mtype normal): BSOD within 1 minute during installation >>>>> - mtype writethrough: Gets much further, BSOD occurs on first VM reboot >>>>> - hostiocache off (mtype normal): Gets much further, BSOD occurs on first VM reboot >>>>> >>>>> None of the configurations provide a working solution - they only delay the crash. >>>>> >>>>> On kernel 6.12.63 with default settings (hostiocache on, mtype normal), Windows installation completes successfully without any crashes. >>>>> >>>>> I have not yet tested with qemu/libvirt. Should I proceed with that test? >>>> >>>> Yes please. Libvirt/qemu is a more common solution among developers. >>>> If you can reproduce it using libvirt/qemu, more btrfs developers can >>>> try to reproduce it and look into it. >>>> >>>> And if not, the cause may shift towards vbox other than btrfs. >>>> >>>> Thanks, >>>> Qu >>>> >>>>> On Sunday, January 11th, 2026 at 10:15 AM, Qu Wenruo wqu@suse.com wrote: >>>>> >>>>>> 在 2026/1/11 20:33, jollycar 写道: >>>>>> >>>>>>> #regzbot introduced: v6.12..v6.18 >>>>>>> >>>>>>> [1.] One line summary of the problem: >>>>>>> VirtualBox VM crashes with BSOD during Windows installation on kernels 6.18+ (works fine on 6.12 LTS) >>>>>>> >>>>>>> [2.] Full description of the problem: >>>>>>> Windows 10 and Windows 11 installation inside VirtualBox consistently crashes with BSOD within 1-3 minutes on Linux kernels 6.18.3 and 6.19-rc3. The same VirtualBox configuration and VM image work perfectly on kernel 6.12 LTS. The BSOD errors vary each time (most recent: 0x80070470 - "file may be corrupt or missing"). The host system remains completely stable with no logged errors. >>>>>>> >>>>>>> [3] Kernel & Hardware: >>>>>>> - Kernel versions tested: >>>>>>> * Working: 6.12.63-1 >>>>>>> * Broken: 6.18.3-2, 6.19.0-rc3-1 >>>>>>> - Distribution: Manjaro Linux >>>>>>> - Architecture: x86_64 >>>>>>> - VirtualBox: 7.2.4 r170995 (vboxdrv vermagic: 6.18.3-2-MANJARO SMP preempt mod_unload) >>>>>>> >>>>>>> [4.] Filesystem and storage: >>>>>>> - Root filesystem: btrfs on LUKS encryption >>>>>>> - Mount options: zstd compression level 3, SSD optimizations, async discard, free space tree >>>>>>> - VM storage: separate btrfs subvolume >>>>>> >>>>>> What's the storage file configuration? Like what's the cache mode setting? >>>>>> I don't know VBox at all, but there may be something similar to >>>>>> libvirt's cache mode (none/unsafe/writethrough etc). >>>>>> >>>>>> More importantly, will tweaking the cache mode change fix the broken >>>>>> kernels? >>>>>> If so it may point to direct IO related behavior changes. >>>>>> >>>>>> And what's the storage file format? QCOW2? RAW? Or whatever format >>>>>> provided by Vbox? >>>>>> >>>>>> And one final question, have you tried qemu (or libvirt + qemu) and can >>>>>> it still be reproduced with qemu? >>>>>> As I'm wondering if the direct IO related change will even affects qemu >>>>>> >>>>>> Thanks, >>>>>> Qu >>>>>> >>>>>>> - btrfs device stats: all zeros (no errors) >>>>>>> >>>>>>> [5.] Reproduction: >>>>>>> - Boot kernel 6.18.3-2 or 6.19.0-rc3 >>>>>>> - Start VirtualBox 7.2.4 r170995 >>>>>>> - Create new Windows 10 or Windows 11 VM >>>>>>> - Begin OS installation >>>>>>> - BSOD occurs within 1-3 minutes with varying errors (latest: 0x80070470) >>>>>>> - Issue is 100% reproducible on 6.18+, never occurs on 6.12 >>>>>>> >>>>>>> Additional context: >>>>>>> - Host system remains completely stable during VM crashes >>>>>>> - No btrfs errors in dmesg or device stats (all zero) >>>>>>> - Issue persists across multiple 6.18/6.19 releases over one month >>>>>>> - VirtualBox 7.2.4 modules load successfully on all kernel versions >>>>>>> >>>>>>> Regards, >>>>>>> Jollycar >