{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-04-23T02:19:26.281","vulnerabilities":[{"cve":{"id":"CVE-2025-68807","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","published":"2026-01-13T16:16:02.857","lastModified":"2026-04-15T00:35:42.020","vulnStatus":"Deferred","cveTags":[],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock: fix race between wbt_enable_default and IO submission\n\nWhen wbt_enable_default() is moved out of queue freezing in elevator_change(),\nit can cause the wbt inflight counter to become negative (-1), leading to hung\ntasks in the writeback path. Tasks get stuck in wbt_wait() because the counter\nis in an inconsistent state.\n\nThe issue occurs because wbt_enable_default() could race with IO submission,\nallowing the counter to be decremented before proper initialization. This manifests\nas:\n\n  rq_wait[0]:\n    inflight:             -1\n    has_waiters:        True\n\nrwb_enabled() checks the state, which can be updated exactly between wbt_wait()\n(rq_qos_throttle()) and wbt_track()(rq_qos_track()), then the inflight counter\nwill become negative.\n\nAnd results in hung task warnings like:\n  task:kworker/u24:39 state:D stack:0 pid:14767\n  Call Trace:\n    rq_qos_wait+0xb4/0x150\n    wbt_wait+0xa9/0x100\n    __rq_qos_throttle+0x24/0x40\n    blk_mq_submit_bio+0x672/0x7b0\n    ...\n\nFix this by:\n\n1. Splitting wbt_enable_default() into:\n   - __wbt_enable_default(): Returns true if wbt_init() should be called\n   - wbt_enable_default(): Wrapper for existing callers (no init)\n   - wbt_init_enable_default(): New function that checks and inits WBT\n\n2. Using wbt_init_enable_default() in blk_register_queue() to ensure\n   proper initialization during queue registration\n\n3. Move wbt_init() out of wbt_enable_default() which is only for enabling\n   disabled wbt from bfq and iocost, and wbt_init() isn't needed. Then the\n   original lock warning can be avoided.\n\n4. Removing the ELEVATOR_FLAG_ENABLE_WBT_ON_EXIT flag and its handling\n   code since it's no longer needed\n\nThis ensures WBT is properly initialized before any IO can be submitted,\npreventing the counter from going negative."},{"lang":"es","value":"En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nblock: corrige la condición de carrera entre wbt_enable_default y el envío de E/S\n\nCuando wbt_enable_default() se mueve fuera de la congelación de la cola en elevator_change(), puede hacer que el contador inflight de wbt se vuelva negativo (-1), lo que lleva a tareas colgadas en la ruta de writeback. Las tareas se quedan atascadas en wbt_wait() porque el contador está en un estado inconsistente.\n\nEl problema ocurre porque wbt_enable_default() podría competir con el envío de E/S, permitiendo que el contador se decremente antes de la inicialización adecuada. Esto se manifiesta como:\n\n  rq_wait[0]:\n    inflight:             -1\n    has_waiters:        True\n\nrwb_enabled() verifica el estado, que puede actualizarse exactamente entre wbt_wait() (rq_qos_throttle()) y wbt_track()(rq_qos_track()), entonces el contador inflight se volverá negativo.\n\nY resulta en advertencias de tareas colgadas como:\n  task:kworker/u24:39 state:D stack:0 pid:14767\n  Call Trace:\n    rq_qos_wait+0xb4/0x150\n    wbt_wait+0xa9/0x100\n    __rq_qos_throttle+0x24/0x40\n    blk_mq_submit_bio+0x672/0x7b0\n    ...\n\nEsto se soluciona mediante:\n\n1. Dividiendo wbt_enable_default() en:\n   - __wbt_enable_default(): Devuelve verdadero si se debe llamar a wbt_init()\n   - wbt_enable_default(): Envoltorio para las funciones que ya lo llaman (sin inicialización)\n   - wbt_init_enable_default(): Nueva función que verifica e inicializa WBT\n\n2. Usando wbt_init_enable_default() en blk_register_queue() para asegurar una inicialización adecuada durante el registro de la cola\n\n3. Moviendo wbt_init() fuera de wbt_enable_default(), que es solo para habilitar wbt deshabilitado de bfq e iocost, y wbt_init() no es necesario. Así se puede evitar la advertencia de bloqueo original.\n\n4. Eliminando la bandera ELEVATOR_FLAG_ENABLE_WBT_ON_EXIT y su código de manejo, ya que ya no es necesario\n\nEsto asegura que WBT se inicialice correctamente antes de que se pueda enviar cualquier E/S, evitando que el contador se vuelva negativo."}],"metrics":{},"references":[{"url":"https://git.kernel.org/stable/c/9869d3a6fed381f3b98404e26e1afc75d680cbf9","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f55201fb3becff6a903fd29f4d1147cc7e91eb0c","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}]}