CVE-2023-52982
In the Linux kernel, the following vulnerability has been resolved:
fscache: Use wait_on_bit() to wait for the freeing of relinquished volume
The freeing of relinquished volume will wake up the pending volume acquisition by using wake_up_bit(), however it is mismatched with wait_var_event() used in fscache_wait_on_volume_collision() and it will never wake up the waiter in the wait-queue because these two functions operate on different wait-queues.
According to the implementation in fscache_wait_on_volume_collision(), if the wake-up of pending acquisition is delayed longer than 20 seconds (e.g., due to the delay of on-demand fd closing), the first wait_var_event_timeout() will timeout and the following wait_var_event() will hang forever as shown below:
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Considering that wake_up_bit() is more selective, so fix it by using wait_on_bit() instead of wait_var_event() to wait for the freeing of relinquished volume. In addition because waitqueue_active() is used in wake_up_bit() and clear_bit() doesn't imply any memory barrier, use clear_and_wake_up_bit() to add the missing memory barrier between cursor->flags and waitqueue_active().
Detalles técnicos trazas, registros y código del informe original
FS-Cache: Potential volume collision new=00000024 old=00000022
......
INFO: task mount:1148 blocked for more than 122 seconds.
Not tainted 6.1.0-rc6+ #1
task:mount state:D stack:0 pid:1148 ppid:1
Call Trace:
<TASK>
__schedule+0x2f6/0xb80
schedule+0x67/0xe0
fscache_wait_on_volume_collision.cold+0x80/0x82
__fscache_acquire_volume+0x40d/0x4e0
erofs_fscache_register_volume+0x51/0xe0 [erofs]
erofs_fscache_register_fs+0x19c/0x240 [erofs]
erofs_fc_fill_super+0x746/0xaf0 [erofs]
vfs_get_super+0x7d/0x100
get_tree_nodev+0x16/0x20
erofs_fc_get_tree+0x20/0x30 [erofs]
vfs_get_tree+0x24/0xb0
path_mount+0x2fa/0xa90
do_mount+0x7c/0xa0
__x64_sys_mount+0x8b/0xe0
do_syscall_64+0x30/0x60
entry_SYSCALL_64_after_hwframe+0x46/0xb0CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.22%
- Percentil entre todas las CVEs puntuadas: 12
- 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)
CWE
- NVD-CWE-noinfo
Referencias
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfscache: Use wait_on_bit() to wait for the freeing of relinquished volume\n\nThe freeing of relinquished volume will wake up the pending volume\nacquisition by using wake_up_bit(), however it is mismatched with\nwait_var_event() used in fscache_wait_on_volume_collision() and it will\nnever wake up the waiter in the wait-queue because these two functions\noperate on different wait-queues.\n\nAccording to the implementation in fscache_wait_on_volume_collision(),\nif the wake-up of pending acquisition is delayed longer than 20 seconds\n(e.g., due to the delay of on-demand fd closing), the first\nwait_var_event_timeout() will timeout and the following wait_var_event()\nwill hang forever as shown below:\n\n FS-Cache: Potential volume collision new=00000024 old=00000022\n ......\n INFO: task mount:1148 blocked for more than 122 seconds.\n Not tainted 6.1.0-rc6+ #1\n task:mount state:D stack:0 pid:1148 ppid:1\n Call Trace:\n <TASK>\n __schedule+0x2f6/0xb80\n schedule+0x67/0xe0\n fscache_wait_on_volume_collision.cold+0x80/0x82\n __fscache_acquire_volume+0x40d/0x4e0\n erofs_fscache_register_volume+0x51/0xe0 [erofs]\n erofs_fscache_register_fs+0x19c/0x240 [erofs]\n erofs_fc_fill_super+0x746/0xaf0 [erofs]\n vfs_get_super+0x7d/0x100\n get_tree_nodev+0x16/0x20\n erofs_fc_get_tree+0x20/0x30 [erofs]\n vfs_get_tree+0x24/0xb0\n path_mount+0x2fa/0xa90\n do_mount+0x7c/0xa0\n __x64_sys_mount+0x8b/0xe0\n do_syscall_64+0x30/0x60\n entry_SYSCALL_64_after_hwframe+0x46/0xb0\n\nConsidering that wake_up_bit() is more selective, so fix it by using\nwait_on_bit() instead of wait_var_event() to wait for the freeing of\nrelinquished volume. In addition because waitqueue_active() is used in\nwake_up_bit() and clear_bit() doesn't imply any memory barrier, use\nclear_and_wake_up_bit() to add the missing memory barrier between\ncursor->flags and waitqueue_active()."
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"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fscache: utilice wait_on_bit() para esperar la liberación del volumen cedido. La liberación del volumen cedido activará la adquisición de volumen pendiente mediante wake_up_bit(), sin embargo no coincide con wait_var_event() utilizado en fscache_wait_on_volume_collision() y nunca activará al que espera en la cola de espera porque estas dos funciones operan en colas de espera diferentes. Según la implementación en fscache_wait_on_volume_collision(), si la activación de una adquisición pendiente se demora más de 20 segundos (por ejemplo, debido a la demora en el cierre del fd a pedido), el primer wait_var_event_timeout() expirará y el siguiente wait_var_event() se colgará para siempre como se muestra a continuación: FS-Cache: Potencial colisión de volumen nuevo=00000024 antiguo=00000022 ...... INFORMACIÓN: montaje de tarea: 1148 bloqueado durante más de 122 segundos. No contaminado 6.1.0-rc6+ #1 task:mount state:D stack:0 pid:1148 ppid:1 Call Trace: __schedule+0x2f6/0xb80 schedule+0x67/0xe0 fscache_wait_on_volume_collision.cold+0x80/0x82 __fscache_acquire_volume+0x40d/0x4e0 erofs_fscache_register_volume+0x51/0xe0 [erofs] erofs_fscache_register_fs+0x19c/0x240 [erofs] erofs_fc_fill_super+0x746/0xaf0 [erofs] vfs_get_super+0x7d/0x100 get_tree_nodev+0x16/0x20 erofs_fc_get_tree+0x20/0x30 [erofs] vfs_get_tree+0x24/0xb0 path_mount+0x2fa/0xa90 do_mount+0x7c/0xa0 __x64_sys_mount+0x8b/0xe0 do_syscall_64+0x30/0x60 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Considering that wake_up_bit() es más selectivo, corríjalo utilizando wait_on_bit() en lugar de wait_var_event() para esperar la liberación del volumen cedido. Además, debido a que waitqueue_active() se usa en wake_up_bit() y clear_bit() no implica ninguna barrera de memoria, use clear_and_wake_up_bit() para agregar la barrera de memoria faltante entre cursor->flags y waitqueue_active()."
}
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"lastModified": "2026-06-17T06:44:03.057",
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