Linux Kernel up to 7.2.7/7.3-rc3 sched/core kernel/sched/core.c set_task_cpu locking

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.7/7.3-rc3 and classified as critical. This affects the function set_task_cpu of the file kernel/sched/core.c of the component sched/core. Executing a manipulation can lead to locking. This vulnerability appears as CVE-2026-98418. The attack requires local access. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 7.2.7/7.3-rc3. This vulnerability affects the function set_task_cpu of the file kernel/sched/core.c of the component sched/core. The manipulation with an unknown input leads to a locking vulnerability. The CWE definition for the vulnerability is CWE-667. The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: sched/core: Avoid false migration warning for proxy donors Proxy execution can move a blocked donor's scheduling context to the lock owner's CPU even when the donor is migration-disabled. The donor does not execute there, and its original execution CPU remains recorded in wake_cpu. set_task_cpu() warns unconditionally for migration-disabled tasks, so a subsequent proxy migration or the wakeup path returning the donor home triggers a false positive: moving a blocked scheduling context does not violate the migration-disabled execution context. For example, creating a mutex owner on CPU1 and a migration-disabled waiter on CPU0 can trigger the following warning: proxy_migrate_repro: donor blocking on CPU0 with migration disabled proxy_migrate_repro: donor moved from CPU0 to CPU1 WARNING: kernel/sched/core.c:3389 at set_task_cpu+0x1d3/0x280 ... Call Trace: try_to_wake_up+0x43f/0x780 __mutex_unlock_slowpath+0x330/0x540 owner_fn+0x9f/0xc0 [proxy_migrate_repro] ... proxy_migrate_repro: donor woke on CPU0, task_cpu=0 proxy_migrate_repro: completed Exclude blocked proxy donors from the warning. The proxy wakeup path restores an executable placement before clearing the blocked state.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-98418 since 09/25/2026. The exploitation appears to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit.

Upgrading to version 7.2.8 or 7.3-rc4 eliminates this vulnerability. Applying the patch e4a442da49fff7619b3cb2988e477022dcea6688/fe3c73d7bc769e7afc252f867a3421fe168b898d is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5
• 7.2.6
• 7.2.7
• 7.3-rc1
• 7.3-rc2
• 7.3-rc3

License

• open-source

Website

• Vendor: https://www.kernel.org/

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