GHSA-H8V6-C5RC-5J48
Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31In the Linux kernel, the following vulnerability has been resolved:
block: skip sync_blockdev() on surprise removal in bdev_mark_dead()
bdev_mark_dead()'s @surprise == true means the device is already gone. The filesystem callback fs_bdev_mark_dead() honours this and skips sync_filesystem(), but the bare block device path (no ->mark_dead op) lost its !surprise guard when the holder ->mark_dead callback was wired up (see Fixes), and now calls sync_blockdev() unconditionally, which can hang forever waiting on writeback that can no longer complete.
syzkaller hit this via nvme_reset_work()'s "I/O queues lost" path: nvme_mark_namespaces_dead() -> blk_mark_disk_dead() -> bdev_mark_dead(bdev, true) -> sync_blockdev() blocks in folio_wait_writeback(), wedging the reset worker and every task waiting on it.
Skip the sync on surprise removal, matching fs_bdev_mark_dead(); invalidate_bdev() still runs. Orderly removal (surprise == false) is unchanged.
Found by FuzzNvme(Syzkaller with FEMU fuzzing framework).
{
"affected": [],
"aliases": [
"CVE-2026-64326"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-25T10:17:14Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: skip sync_blockdev() on surprise removal in bdev_mark_dead()\n\nbdev_mark_dead()\u0027s @surprise == true means the device is already gone.\nThe filesystem callback fs_bdev_mark_dead() honours this and skips\nsync_filesystem(), but the bare block device path (no -\u003emark_dead op)\nlost its !surprise guard when the holder -\u003emark_dead callback was wired\nup (see Fixes), and now calls sync_blockdev() unconditionally, which can\nhang forever waiting on writeback that can no longer complete.\n\nsyzkaller hit this via nvme_reset_work()\u0027s \"I/O queues lost\" path:\nnvme_mark_namespaces_dead() -\u003e blk_mark_disk_dead() -\u003e\nbdev_mark_dead(bdev, true) -\u003e sync_blockdev() blocks in\nfolio_wait_writeback(), wedging the reset worker and every task waiting\non it.\n\nSkip the sync on surprise removal, matching fs_bdev_mark_dead();\ninvalidate_bdev() still runs. Orderly removal (surprise == false) is\nunchanged.\n\nFound by FuzzNvme(Syzkaller with FEMU fuzzing framework).",
"id": "GHSA-h8v6-c5rc-5j48",
"modified": "2026-07-25T12:31:31Z",
"published": "2026-07-25T12:31:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64326"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9818bcae3c0ca1dde4b9a334125c46676e0a9b29"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aa4c4a9315764b2b7a7182e72cc5ea87520436b4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d6998ddd507c81e3829489a6ead23f17f5acb7fe"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f41cf35ee2a1e31374b3f54e7579c55153506e70"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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