CVE-2026-98418

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.