CVE-2022-50103
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-06-18

Last updated on: 2025-11-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed With cgroup v2, the cpuset's cpus_allowed mask can be empty indicating that the cpuset will just use the effective CPUs of its parent. So cpuset_can_attach() can call task_can_attach() with an empty mask. This can lead to cpumask_any_and() returns nr_cpu_ids causing the call to dl_bw_of() to crash due to percpu value access of an out of bound CPU value. For example: [80468.182258] BUG: unable to handle page fault for address: ffffffff8b6648b0 : [80468.191019] RIP: 0010:dl_cpu_busy+0x30/0x2b0 : [80468.207946] Call Trace: [80468.208947] cpuset_can_attach+0xa0/0x140 [80468.209953] cgroup_migrate_execute+0x8c/0x490 [80468.210931] cgroup_update_dfl_csses+0x254/0x270 [80468.211898] cgroup_subtree_control_write+0x322/0x400 [80468.212854] kernfs_fop_write_iter+0x11c/0x1b0 [80468.213777] new_sync_write+0x11f/0x1b0 [80468.214689] vfs_write+0x1eb/0x280 [80468.215592] ksys_write+0x5f/0xe0 [80468.216463] do_syscall_64+0x5c/0x80 [80468.224287] entry_SYSCALL_64_after_hwframe+0x44/0xae Fix that by using effective_cpus instead. For cgroup v1, effective_cpus is the same as cpus_allowed. For v2, effective_cpus is the real cpumask to be used by tasks within the cpuset anyway. Also update task_can_attach()'s 2nd argument name to cs_effective_cpus to reflect the change. In addition, a check is added to task_can_attach() to guard against the possibility that cpumask_any_and() may return a value >= nr_cpu_ids.
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Meta Information
Published
2025-06-18
Last Modified
2025-11-19
Generated
2026-05-07
AI Q&A
2025-06-18
EPSS Evaluated
2026-05-05
NVD
CVE-2022-50103
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-125 The product reads data past the end, or before the beginning, of the intended buffer.
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's scheduler and cpuset code where, with cgroup v2, the cpuset's cpus_allowed mask can be empty. This causes a function to incorrectly handle CPU masks, leading to an out-of-bounds access and a kernel panic (crash). The issue arises because the code uses cpus_allowed directly instead of the effective CPU mask, which can be empty in cgroup v2, causing a crash when accessing CPU-specific data. The fix involves using the effective CPU mask and adding checks to prevent out-of-bound CPU accesses.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash (panic) when handling certain cpuset configurations under cgroup v2. This can lead to system instability, unexpected downtime, and potential loss of service or data availability.


What immediate steps should I take to mitigate this vulnerability?

Apply the Linux kernel update that includes the fix for this vulnerability, which replaces the use of cpus_allowed with effective_cpus in the cpuset code and adds necessary checks to prevent crashes. Until the patch is applied, avoid using cgroup v2 cpusets with empty cpus_allowed masks to prevent triggering the issue.


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