CVE-2026-68132
Estado: RecibidaSin puntuar—
In the Linux kernel, the following vulnerability has been resolved:
super: fix emergency thaw deadlock on frozen block devices
do_thaw_all_callback() calls bdev_thaw() while holding sb->s_umount exclusively. If the block device was frozen via bdev_freeze() dropping the last block layer freeze reference calls fs_bdev_thaw() which reacquires s_umount:
The emergency thaw worker deadlocks against itself holding both s_umount and bd_fsfreeze_mutex. That fscks any subsequent unmount, freeze, or thaw of that filesystem and block device.
bdev_super_lock() even documents the violated requirement with lockdep_assert_not_held(&sb->s_umount).
Leer descripción completaMostrar menos
Acquiring bd_fsfreeze_mutex under s_umount also inverts the bd_fsfreeze_mutex vs. s_umount ordering established by bdev_{freeze,thaw}() and can thus ABBA against a concurrent block-layer freeze even when the recursive path isn't hit.
Fix this by not holding s_umount around the bdev_thaw() loop at all. Pin the superblock with an active reference instead as filesystems_freeze_callback() does. The active reference keeps the superblock from being shut down and so ->s_bdev stays valid without holding s_umount. The block-layer-held freeze is dropped by fs_bdev_thaw() with FREEZE_MAY_NEST | FREEZE_HOLDER_USERSPACE exactly as a regular unfreeze would and thaw_super_locked() handles filesystem-level freezes as before.
The emergency thaw path has deadlocked like this in one form or another for a long long time but the current exclusively-held shape dates back to commit [1] where thaw_bdev() already ended in thaw_super() with s_umount held by do_thaw_all_callback().
Detalles técnicos trazas, registros y código del informe original
do_thaw_all_callback(sb)
super_lock_excl(sb) # holds sb->s_umount
bdev_thaw(sb->s_bdev)
mutex_lock(&bdev->bd_fsfreeze_mutex)
# bd_fsfreeze_count drops 1 -> 0
bd_holder_ops->thaw == fs_bdev_thaw
get_bdev_super(bdev)
bdev_super_lock(bdev, true)
super_lock(sb, true)
down_write(&sb->s_umount) # same task: deadlock
[ 81.878470] sysrq: Show Blocked State
[ 81.880140] task:kworker/0:1 state:D stack:0 pid:11 tgid:11 ppid:2 task_flags:0x4208060 flags:0x00080000
[ 81.884876] Workqueue: events do_thaw_all
[ 81.886656] Call Trace:
[ 81.887759] <TASK>
[ 81.888763] __schedule+0x579/0x1420
[ 81.890372] schedule+0x3a/0x100
[ 81.891794] schedule_preempt_disabled+0x15/0x30
[ 81.893848] rwsem_down_write_slowpath+0x1ea/0x900
[ 81.895191] ? __pfx_do_thaw_all_callback+0x10/0x10
[ 81.896528] down_write+0xbd/0xc0
[ 81.897505] super_lock+0x91/0x180
[ 81.898457] ? __mutex_lock+0xa99/0x1140
[ 81.900748] ? __mutex_unlock_slowpath+0x1f/0x400
[ 81.902069] bdev_super_lock+0x5b/0x150
[ 81.903132] get_bdev_super+0x10/0x60
[ 81.904042] fs_bdev_thaw+0x23/0xf0
[ 81.904755] bdev_thaw+0x82/0x100
[ 81.905484] do_thaw_all_callback+0x2c/0x50
[ 81.906298] __iterate_supers+0x5d/0x130
[ 81.907067] do_thaw_all+0x20/0x40
[ 81.907739] process_one_work+0x206/0x5e0
[ 81.908545] worker_thread+0x1e2/0x3c0
[ 81.909339] ? __pfx_worker_thread+0x10/0x10
[ 81.910171] kthread+0xf4/0x130
[ 81.910799] ? __pfx_kthread+0x10/0x10
[ 81.911528] ret_from_fork+0x2e2/0x3b0
[ 81.912259] ? __pfx_kthread+0x10/0x10
[ 81.913010] ret_from_fork_asm+0x1a/0x30
[ 81.913806] </TASK>CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.18%
- Percentil entre todas las CVEs puntuadas: 7
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/05536cad35f27b520d4b6f0e57c8cc5bfb6b0502
- https://git.kernel.org/stable/c/2a1127c1c58b4f15a93f2fd56ff7c2c3d611d5c5
- https://git.kernel.org/stable/c/4c483644d1a7709efe7d1be7dbf88cf4008a7864
- https://git.kernel.org/stable/c/63d78b546eefc38ad9898dc839bfc94811ede547
- https://git.kernel.org/stable/c/749d7aa0377aae32af8c0a4ad43371e7bf830ab5
- https://git.kernel.org/stable/c/96248aeddde794227a49af1a332a1e21b3c15d56
- https://git.kernel.org/stable/c/99719b5da9320ed344daee87d9c73d321a98f252
- https://git.kernel.org/stable/c/c202aa03388fd1889b7aa4f7d677c49e22cd9700
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-68132",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "08fdc8a0138afaf324296a342f32ad26ec465e43",
"lessThan": "96248aeddde794227a49af1a332a1e21b3c15d56",
"versionType": "git"
},
{
"status": "affected",
"version": "08fdc8a0138afaf324296a342f32ad26ec465e43",
"lessThan": "c202aa03388fd1889b7aa4f7d677c49e22cd9700",
"versionType": "git"
},
{
"status": "affected",
"version": "08fdc8a0138afaf324296a342f32ad26ec465e43",
"lessThan": "2a1127c1c58b4f15a93f2fd56ff7c2c3d611d5c5",
"versionType": "git"
},
{
"status": "affected",
"version": "08fdc8a0138afaf324296a342f32ad26ec465e43",
"lessThan": "05536cad35f27b520d4b6f0e57c8cc5bfb6b0502",
"versionType": "git"
},
{
"status": "affected",
"version": "08fdc8a0138afaf324296a342f32ad26ec465e43",
"lessThan": "99719b5da9320ed344daee87d9c73d321a98f252",
"versionType": "git"
},
{
"status": "affected",
"version": "08fdc8a0138afaf324296a342f32ad26ec465e43",
"lessThan": "63d78b546eefc38ad9898dc839bfc94811ede547",
"versionType": "git"
},
{
"status": "affected",
"version": "08fdc8a0138afaf324296a342f32ad26ec465e43",
"lessThan": "4c483644d1a7709efe7d1be7dbf88cf4008a7864",
"versionType": "git"
},
{
"status": "affected",
"version": "08fdc8a0138afaf324296a342f32ad26ec465e43",
"lessThan": "749d7aa0377aae32af8c0a4ad43371e7bf830ab5",
"versionType": "git"
}
],
"programFiles": [
"fs/super.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.17"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.17",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.266",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.217",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.105",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/super.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-10T13:19:58.607",
"references": [
{
"url": "https://git.kernel.org/stable/c/05536cad35f27b520d4b6f0e57c8cc5bfb6b0502",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/2a1127c1c58b4f15a93f2fd56ff7c2c3d611d5c5",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/4c483644d1a7709efe7d1be7dbf88cf4008a7864",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/63d78b546eefc38ad9898dc839bfc94811ede547",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/749d7aa0377aae32af8c0a4ad43371e7bf830ab5",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/96248aeddde794227a49af1a332a1e21b3c15d56",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/99719b5da9320ed344daee87d9c73d321a98f252",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c202aa03388fd1889b7aa4f7d677c49e22cd9700",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "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] <TASK>\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] </TASK>\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()."
}
],
"lastModified": "2026-08-23T13:16:33.470",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}