{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-68132", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-68132", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-08-10T11:58:55.196Z", "updatedAt": "2026-08-23T12:45:53.613Z", "importedAt": "2026-10-24T01:58:25.636Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "super: fix emergency thaw deadlock on frozen block devices", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nsuper: fix emergency thaw deadlock on frozen block devices\n\ndo_thaw_all_callback() calls bdev_thaw() while holding sb->s_umount\nexclusively. If the block device was frozen via bdev_freeze() dropping\nthe last block layer freeze reference calls fs_bdev_thaw() which\nreacquires s_umount:\n\n do_thaw_all_callback(sb)\n super_lock_excl(sb) # holds sb->s_umount\n bdev_thaw(sb->s_bdev)\n mutex_lock(&bdev->bd_fsfreeze_mutex)\n # bd_fsfreeze_count drops 1 -> 0\n bd_holder_ops->thaw == fs_bdev_thaw\n get_bdev_super(bdev)\n bdev_super_lock(bdev, true)\n super_lock(sb, true)\n down_write(&sb->s_umount) # same task: deadlock\n\nThe emergency thaw worker deadlocks against itself holding both\ns_umount and bd_fsfreeze_mutex. That fscks any subsequent unmount,\nfreeze, or thaw of that filesystem and block device.\n\n [ 81.878470] sysrq: Show Blocked State\n [ 81.880140] task:kworker/0:1 state:D stack:0 pid:11 tgid:11 ppid:2 task_flags:0x4208060 flags:0x00080000\n [ 81.884876] Workqueue: events do_thaw_all\n [ 81.886656] Call Trace:\n [ 81.887759] \n [ 81.888763] __schedule+0x579/0x1420\n [ 81.890372] schedule+0x3a/0x100\n [ 81.891794] schedule_preempt_disabled+0x15/0x30\n [ 81.893848] rwsem_down_write_slowpath+0x1ea/0x900\n [ 81.895191] ? __pfx_do_thaw_all_callback+0x10/0x10\n [ 81.896528] down_write+0xbd/0xc0\n [ 81.897505] super_lock+0x91/0x180\n [ 81.898457] ? __mutex_lock+0xa99/0x1140\n [ 81.900748] ? __mutex_unlock_slowpath+0x1f/0x400\n [ 81.902069] bdev_super_lock+0x5b/0x150\n [ 81.903132] get_bdev_super+0x10/0x60\n [ 81.904042] fs_bdev_thaw+0x23/0xf0\n [ 81.904755] bdev_thaw+0x82/0x100\n [ 81.905484] do_thaw_all_callback+0x2c/0x50\n [ 81.906298] __iterate_supers+0x5d/0x130\n [ 81.907067] do_thaw_all+0x20/0x40\n [ 81.907739] process_one_work+0x206/0x5e0\n [ 81.908545] worker_thread+0x1e2/0x3c0\n [ 81.909339] ? __pfx_worker_thread+0x10/0x10\n [ 81.910171] kthread+0xf4/0x130\n [ 81.910799] ? __pfx_kthread+0x10/0x10\n [ 81.911528] ret_from_fork+0x2e2/0x3b0\n [ 81.912259] ? __pfx_kthread+0x10/0x10\n [ 81.913010] ret_from_fork_asm+0x1a/0x30\n [ 81.913806] \n\nbdev_super_lock() even documents the violated requirement with\nlockdep_assert_not_held(&sb->s_umount).\n\nAcquiring bd_fsfreeze_mutex under s_umount also inverts the\nbd_fsfreeze_mutex vs. s_umount ordering established by\nbdev_{freeze,thaw}() and can thus ABBA against a concurrent block-layer\nfreeze even when the recursive path isn't hit.\n\nFix this by not holding s_umount around the bdev_thaw() loop at all. Pin\nthe superblock with an active reference instead as\nfilesystems_freeze_callback() does. The active reference keeps the\nsuperblock from being shut down and so ->s_bdev stays valid without\nholding s_umount. The block-layer-held freeze is dropped by\nfs_bdev_thaw() with FREEZE_MAY_NEST | FREEZE_HOLDER_USERSPACE exactly as\na regular unfreeze would and thaw_super_locked() handles\nfilesystem-level freezes as before.\n\nThe emergency thaw path has deadlocked like this in one form or\nanother for a long long time but the current exclusively-held\nshape dates back to commit [1] where thaw_bdev() already ended in\nthaw_super() with s_umount held by do_thaw_all_callback().", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "08fdc8a0138afaf324296a342f32ad26ec465e43", "status": "affected", "versionType": "git", "lessThan": "96248aeddde794227a49af1a332a1e21b3c15d56" }, { "version": "08fdc8a0138afaf324296a342f32ad26ec465e43", "status": "affected", "versionType": "git", "lessThan": "c202aa03388fd1889b7aa4f7d677c49e22cd9700" }, { "version": "08fdc8a0138afaf324296a342f32ad26ec465e43", "status": "affected", "versionType": "git", "lessThan": "2a1127c1c58b4f15a93f2fd56ff7c2c3d611d5c5" }, { "version": "08fdc8a0138afaf324296a342f32ad26ec465e43", "status": "affected", "versionType": "git", "lessThan": "05536cad35f27b520d4b6f0e57c8cc5bfb6b0502" }, { "version": "08fdc8a0138afaf324296a342f32ad26ec465e43", "status": "affected", "versionType": "git", "lessThan": "99719b5da9320ed344daee87d9c73d321a98f252" }, { "version": "08fdc8a0138afaf324296a342f32ad26ec465e43", "status": "affected", "versionType": "git", "lessThan": "63d78b546eefc38ad9898dc839bfc94811ede547" }, { "version": "08fdc8a0138afaf324296a342f32ad26ec465e43", "status": "affected", "versionType": "git", "lessThan": "4c483644d1a7709efe7d1be7dbf88cf4008a7864" }, { "version": "08fdc8a0138afaf324296a342f32ad26ec465e43", "status": "affected", "versionType": "git", "lessThan": "749d7aa0377aae32af8c0a4ad43371e7bf830ab5" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.17", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.17" }, { "version": "5.10.266", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.217", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.184", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.153", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.105", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.42", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.6", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }