Bug 2552192 (CVE-2026-98418) - CVE-2026-98418 kernel: sched/core: Avoid false migration warning for proxy donors
Summary: CVE-2026-98418 kernel: sched/core: Avoid false migration warning for proxy do...
Keywords:
Status: NEW
Alias: CVE-2026-98418
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-14 13:42 UTC by OSIDB Bzimport
Modified: 2026-10-16 11:36 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-10-14 13:42:16 UTC
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.


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