Описание
In the Linux kernel, the following vulnerability has been resolved:
libceph: make calc_target() set t->paused, not just clear it
Currently calc_target() clears t->paused if the request shouldn't be
paused anymore, but doesn't ever set t->paused even though it's able to
determine when the request should be paused. Setting t->paused is left
to __submit_request() which is fine for regular requests but doesn't
work for linger requests -- since __submit_request() doesn't operate
on linger requests, there is nowhere for lreq->t.paused to be set.
One consequence of this is that watches don't get reestablished on
paused -> unpaused transitions in cases where requests have been paused
long enough for the (paused) unwatch request to time out and for the
subsequent (re)watch request to enter the paused state. On top of the
watch not getting reestablished, rbd_reregister_watch() gets stuck with
rbd_dev->watch_mutex held:
rbd_register_watch
__rbd_register_watch
ceph_osdc_watch
linger_reg_commit_wait
It's waiting for lreq->reg_commit_wait to be completed, but for that to
happen the respective request needs to end up on need_resend_linger list
and be kicked when requests are unpaused. There is no chance for that
if the request in question is never marked paused in the first place.
The fact that rbd_dev->watch_mutex remains taken out forever then
prevents the image from getting unmapped -- "rbd unmap" would inevitably
hang in D state on an attempt to grab the mutex.
A deadlock vulnerability was found in the Linux kernel's Ceph client library (libceph). The calc_target() function clears the paused flag for requests but never sets it for linger requests, as that logic was only in __submit_request(). When watch requests are paused long enough to timeout and need reestablishment, they never get marked as paused and thus never get resent when unpaused. This causes rbd_reregister_watch() to wait indefinitely with rbd_dev->watch_mutex held.
Отчет
This vulnerability affects systems using Ceph RBD (RADOS Block Device) storage. When network conditions cause watch requests to be paused for extended periods, the subsequent deadlock prevents RBD images from being unmapped, causing "rbd unmap" commands to hang in D state. Recovery requires a system reboot.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 8 | kernel | Affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 9 | kernel | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected |
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Дополнительная информация
Статус:
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: libceph: make calc_target() set t->paused, not just clear it Currently calc_target() clears t->paused if the request shouldn't be paused anymore, but doesn't ever set t->paused even though it's able to determine when the request should be paused. Setting t->paused is left to __submit_request() which is fine for regular requests but doesn't work for linger requests -- since __submit_request() doesn't operate on linger requests, there is nowhere for lreq->t.paused to be set. One consequence of this is that watches don't get reestablished on paused -> unpaused transitions in cases where requests have been paused long enough for the (paused) unwatch request to time out and for the subsequent (re)watch request to enter the paused state. On top of the watch not getting reestablished, rbd_reregister_watch() gets stuck with rbd_dev->watch_mutex held: rbd_register_watch __rbd_register_watch ceph_osdc_watch linger_reg_commi...
In the Linux kernel, the following vulnerability has been resolved: libceph: make calc_target() set t->paused, not just clear it Currently calc_target() clears t->paused if the request shouldn't be paused anymore, but doesn't ever set t->paused even though it's able to determine when the request should be paused. Setting t->paused is left to __submit_request() which is fine for regular requests but doesn't work for linger requests -- since __submit_request() doesn't operate on linger requests, there is nowhere for lreq->t.paused to be set. One consequence of this is that watches don't get reestablished on paused -> unpaused transitions in cases where requests have been paused long enough for the (paused) unwatch request to time out and for the subsequent (re)watch request to enter the paused state. On top of the watch not getting reestablished, rbd_reregister_watch() gets stuck with rbd_dev->watch_mutex held: rbd_register_watch __rbd_register_watch ceph_osdc_watch
In the Linux kernel, the following vulnerability has been resolved: l ...
In the Linux kernel, the following vulnerability has been resolved: libceph: make calc_target() set t->paused, not just clear it Currently calc_target() clears t->paused if the request shouldn't be paused anymore, but doesn't ever set t->paused even though it's able to determine when the request should be paused. Setting t->paused is left to __submit_request() which is fine for regular requests but doesn't work for linger requests -- since __submit_request() doesn't operate on linger requests, there is nowhere for lreq->t.paused to be set. One consequence of this is that watches don't get reestablished on paused -> unpaused transitions in cases where requests have been paused long enough for the (paused) unwatch request to time out and for the subsequent (re)watch request to enter the paused state. On top of the watch not getting reestablished, rbd_reregister_watch() gets stuck with rbd_dev->watch_mutex held: rbd_register_watch __rbd_register_watch ceph_osdc_watch ...
ELSA-2026-50144: Unbreakable Enterprise kernel security update (IMPORTANT)
5.5 Medium
CVSS3