cbcvebase.
CVE-2025-68780
published 2026-01-13

CVE-2025-68780: In the Linux kernel, the following vulnerability has been resolved: sched/deadline: only set free_cpus for online runqueues Commit 16b269436b72…

PriorityP424high7.8
EPSS
0.17%
7.0th percentile
In the Linux kernel, the following vulnerability has been resolved: sched/deadline: only set free_cpus for online runqueues Commit 16b269436b72 ("sched/deadline: Modify cpudl::free_cpus to reflect rd->online") introduced the cpudl_set/clear_freecpu functions to allow the cpu_dl::free_cpus mask to be manipulated by the deadline scheduler class rq_on/offline callbacks so the mask would also reflect this state. Commit 9659e1eeee28 ("sched/deadline: Remove cpu_active_mask from cpudl_find()") removed the check of the cpu_active_mask to save some processing on the premise that the cpudl::free_cpus mask already reflected the runqueue online state. Unfortunately, there are cases where it is possible for the cpudl_clear function to set the free_cpus bit for a CPU when the deadline runqueue is offline. When this occurs while a CPU is connected to the default root domain the flag may retain the bad state after the CPU has been unplugged. Later, a different CPU that is transitioning through the default root domain may push a deadline task to the powered down CPU when cpudl_find sees its free_cpus bit is set. If this happens the task will not have the opportunity to run. One example is outlined here: https://lore.kernel.org/lkml/[email protected] Another occurs when the last deadline task is migrated from a CPU that has an offlined runqueue. The dequeue_task member of the deadline scheduler class will eventually call cpudl_clear and set the free_cpus bit for the CPU. This commit modifies the cpudl_clear function to be aware of the online state of the deadline runqueue so that the free_cpus mask can be updated appropriately. It is no longer necessary to manage the mask outside of the cpudl_set/clear functions so the cpudl_set/clear_freecpu functions are removed. In addition, since the free_cpus mask is now only updated under the cpudl lock the code was changed to use the non-atomic __cpumask functions.

Affected

48 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.162-1 (bookworm)linux 6.1.162-1 (bookworm)
debianlinux-6.1< linux 6.1.162-1 (bookworm)linux 6.1.162-1 (bookworm)
linuxlinux
linuxlinux>= 9659e1eeee28f7025b6545934d644d19e9c6e603 < 9019e399684e3cc68c4a3f050e268f74d69c13179019e399684e3cc68c4a3f050e268f74d69c1317
linuxlinux>= 9659e1eeee28f7025b6545934d644d19e9c6e603 < fb36846cbcc936954f2ad2bffdff13d16c0be08afb36846cbcc936954f2ad2bffdff13d16c0be08a
linuxlinux>= 9659e1eeee28f7025b6545934d644d19e9c6e603 < 91e448e69aca4bb0ba2e998eb3e555644db7322b91e448e69aca4bb0ba2e998eb3e555644db7322b
linuxlinux>= 9659e1eeee28f7025b6545934d644d19e9c6e603 < dbc61834b0412435df21c71410562d933e4eba49dbc61834b0412435df21c71410562d933e4eba49
linuxlinux>= 9659e1eeee28f7025b6545934d644d19e9c6e603 < 3ed049fbfb4d75b4e0b8ab54c934f485129d5dc83ed049fbfb4d75b4e0b8ab54c934f485129d5dc8
linuxlinux>= 9659e1eeee28f7025b6545934d644d19e9c6e603 < 382748c05e58a9f1935f5a653c352422375566ea382748c05e58a9f1935f5a653c352422375566ea
linuxlinux_kernel>= 0 < 6.1.162-16.1.162-1
linuxlinux_kernel>= 0 < 6.12.69-16.12.69-1
linuxlinux_kernel>= 0 < 6.18.3-16.18.3-1
linuxlinux_kernel>= 0 < 5.15.0-173.1835.15.0-173.183
linuxlinux_kernel>= 4.0.0 < 5.15.1985.15.198
linuxlinux_kernel>= 5.16.0 < 6.1.1606.1.160
linuxlinux_kernel>= 6.13.0 < 6.18.36.18.3
linuxlinux_kernel>= 6.2.0 < 6.6.1206.6.120
linuxlinux_kernel>= 6.7.0 < 6.12.646.12.64
ubuntulinux-aws
ubuntulinux-aws-6.17
ubuntulinux-aws-fips
ubuntulinux-azure
ubuntulinux-azure-5.15
ubuntulinux-azure-6.17
ubuntulinux-azure-6.8

CVSS provenance

osv7.8HIGH
vendor_ubuntu7.8HIGH
vendor_redhat5.5LOW
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