CVE-2025-68823 (GCVE-0-2025-68823)
Vulnerability from cvelistv5
Published
2026-01-13 15:29
Modified
2026-02-12 08:19
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ublk: fix deadlock when reading partition table
When one process(such as udev) opens ublk block device (e.g., to read
the partition table via bdev_open()), a deadlock[1] can occur:
1. bdev_open() grabs disk->open_mutex
2. The process issues read I/O to ublk backend to read partition table
3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()
runs bio->bi_end_io() callbacks
4. If this triggers fput() on file descriptor of ublk block device, the
work may be deferred to current task's task work (see fput() implementation)
5. This eventually calls blkdev_release() from the same context
6. blkdev_release() tries to grab disk->open_mutex again
7. Deadlock: same task waiting for a mutex it already holds
The fix is to run blk_update_request() and blk_mq_end_request() with bottom
halves disabled. This forces blkdev_release() to run in kernel work-queue
context instead of current task work context, and allows ublk server to make
forward progress, and avoids the deadlock.
[axboe: rewrite comment in ublk]
References
| URL | Tags | |
|---|---|---|
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/block/ublk_drv.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"versionType": "git"
},
{
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"versionType": "git"
},
{
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{
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}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/block/ublk_drv.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.0"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.124",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.70",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.19",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"vulnerable": true
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{
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix deadlock when reading partition table\n\nWhen one process(such as udev) opens ublk block device (e.g., to read\nthe partition table via bdev_open()), a deadlock[1] can occur:\n\n1. bdev_open() grabs disk-\u003eopen_mutex\n2. The process issues read I/O to ublk backend to read partition table\n3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()\n runs bio-\u003ebi_end_io() callbacks\n4. If this triggers fput() on file descriptor of ublk block device, the\n work may be deferred to current task\u0027s task work (see fput() implementation)\n5. This eventually calls blkdev_release() from the same context\n6. blkdev_release() tries to grab disk-\u003eopen_mutex again\n7. Deadlock: same task waiting for a mutex it already holds\n\nThe fix is to run blk_update_request() and blk_mq_end_request() with bottom\nhalves disabled. This forces blkdev_release() to run in kernel work-queue\ncontext instead of current task work context, and allows ublk server to make\nforward progress, and avoids the deadlock.\n\n[axboe: rewrite comment in ublk]"
}
],
"providerMetadata": {
"dateUpdated": "2026-02-12T08:19:29.311Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/64c0b7e2293757e8320f13434cd809f1c9257a62"
},
{
"url": "https://git.kernel.org/stable/c/9bcc47343ee0ef346aa7b2b460c8ff56bd882fe7"
},
{
"url": "https://git.kernel.org/stable/c/0460e09a614291f06c008443f47393c37b7358e7"
},
{
"url": "https://git.kernel.org/stable/c/c258f5c4502c9667bccf5d76fa731ab9c96687c1"
}
],
"title": "ublk: fix deadlock when reading partition table",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2025-68823",
"datePublished": "2026-01-13T15:29:25.392Z",
"dateReserved": "2025-12-24T10:30:51.048Z",
"dateUpdated": "2026-02-12T08:19:29.311Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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