Описание
In the Linux kernel, the following vulnerability has been resolved:
ceph: do not repeat ceph_trim_dentries() if no progress possible
ceph_cap_reclaim_work() re-queues itself for as long as
ceph_trim_dentries() returns -EAGAIN, which happens whenever a lease
walk exhausts its nr_to_scan budget. This creates a busy loop that
consumes CPU without making any progress when there is nothing to
reclaim: with no cap pressure (count==0) and every scanned lease
still valid, each pass runs the full scan budget down to zero and
returns -EAGAIN, only to be queued again immediately.
The dir-lease walk made this worse. When expire_dir_lease is
false (i.e. we have no intention of reclaiming dir leases),
__dir_lease_check() returned TOUCH for every valid lease. TOUCH
moves the dentry to the tail of the list and resets di->time via
__dentry_dir_lease_touch(), so a walk over N valid leases pointlessly
rewrote the list, refreshed the timestamps (preventing them from ever
aging out) a
EPSS
7.5 High
CVSS3
Дефекты
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: ceph: do not repeat ceph_trim_dentries() if no progress possible ceph_cap_reclaim_work() re-queues itself for as long as ceph_trim_dentries() returns -EAGAIN, which happens whenever a lease walk exhausts its `nr_to_scan` budget. This creates a busy loop that consumes CPU without making any progress when there is nothing to reclaim: with no cap pressure (`count==0`) and every scanned lease still valid, each pass runs the full scan budget down to zero and returns `-EAGAIN`, only to be queued again immediately. The dir-lease walk made this worse. When `expire_dir_lease` is `false` (i.e. we have no intention of reclaiming dir leases), __dir_lease_check() returned `TOUCH` for every valid lease. `TOUCH` moves the dentry to the tail of the list and resets `di->time` via __dentry_dir_lease_touch(), so a walk over N valid leases pointlessly rewrote the list, refreshed the timestamps (preventing them from ever aging out) a...
In the Linux kernel, the following vulnerability has been resolved: ceph: do not repeat ceph_trim_dentries() if no progress possible ceph_cap_reclaim_work() re-queues itself for as long as ceph_trim_dentries() returns -EAGAIN, which happens whenever a lease walk exhausts its `nr_to_scan` budget. This creates a busy loop that consumes CPU without making any progress when there is nothing to reclaim: with no cap pressure (`count==0`) and every scanned lease still valid, each pass runs the full scan budget down to zero and returns `-EAGAIN`, only to be queued again immediately. The dir-lease walk made this worse. When `expire_dir_lease` is `false` (i.e. we have no intention of reclaiming dir leases), __dir_lease_check() returned `TOUCH` for every valid lease. `TOUCH` moves the dentry to the tail of the list and resets `di->time` via __dentry_dir_lease_touch(), so a walk over N valid leases pointlessly rewrote the list, refreshed the timestamps (preventing them from ever aging out) a...
In the Linux kernel, the following vulnerability has been resolved: c ...
In the Linux kernel, the following vulnerability has been resolved: ceph: do not repeat ceph_trim_dentries() if no progress possible ceph_cap_reclaim_work() re-queues itself for as long as ceph_trim_dentries() returns -EAGAIN, which happens whenever a lease walk exhausts its `nr_to_scan` budget. This creates a busy loop that consumes CPU without making any progress when there is nothing to reclaim: with no cap pressure (`count==0`) and every scanned lease still valid, each pass runs the full scan budget down to zero and returns `-EAGAIN`, only to be queued again immediately. The dir-lease walk made this worse. When `expire_dir_lease` is `false` (i.e. we have no intention of reclaiming dir leases), __dir_lease_check() returned `TOUCH` for every valid lease. `TOUCH` moves the dentry to the tail of the list and resets `di->time` via __dentry_dir_lease_touch(), so a walk over N valid leases pointlessly rewrote the list, refreshed the timestamps (preventing them from ever aging out...
EPSS
7.5 High
CVSS3