In the Linux kernel, the following vulnerability has been resolved:
sched/deadline: Stop dl_server before CPU goes offline
IBM CI tool reported kernel warning[1] when running a CPU removal operation through drmgr[2]. i.e "drmgr -c cpu -r -q 1"
WARNING: CPU: 0 PID: 0 at kernel/sched/cpudeadline.c:219 cpudl_set+0x58/0x170 NIP [c0000000002b6ed8] cpudl_set+0x58/0x170 LR [c0000000002b7cb8] dl_server_timer+0x168/0x2a0 Call Trace: [c000000002c2f8c0] init_stack+0x78c0/0x8000 (unreliable) [c0000000002b7cb8] dl_server_timer+0x168/0x2a0 [c00000000034df84] __hrtimer_run_queues+0x1a4/0x390 [c00000000034f624] hrtimer_interrupt+0x124/0x300 [c00000000002a230] timer_interrupt+0x140/0x320
Git bisects to: commit 4ae8d9aa9f9d ("sched/deadline: Fix dl_server getting stuck")
This happens since: - dl_server hrtimer gets enqueued close to cpu offline, when kthread_park enqueues a fair task. - CPU goes offline and drmgr removes it from cpu_present_mask. - hrtimer fires and warning is hit.
Fix it by stopping the dl_server before CPU is marked dead.
[1]: https://lore.kernel.org/all/[email protected]/ [2]: https://github.com/ibm-power-utilities/powerpc-utils/tree/next/src/drmgr
[sshegde: wrote the changelog and tested it]
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Ubuntu | — | Upgrade linux-image-gcp-64k-6.17Upgrade linux-image-generic-6.17Upgrade linux-image-aws-64kUpgrade linux-image-aws-6.17Upgrade linux-image-6.17.0-1008-azureUpgrade linux-image-virtualUpgrade linux-image-6.17.0-1007-gcp-64kUpgrade linux-image-oracle-64k-6.17Upgrade linux-image-azure-6.17Upgrade linux-image-generic-64kUpgrade linux-image-6.17.0-14-generic-64kUpgrade linux-image-genericUpgrade linux-image-6.17.0-1011-oemUpgrade linux-image-6.17.0-1007-aws-64kUpgrade linux-image-6.17.0-1007-oracle-64kUpgrade linux-image-aws-64k-6.17Upgrade linux-image-generic-64k-6.17Upgrade linux-image-6.17.0-1007-oracleUpgrade linux-image-6.17.0-1007-awsUpgrade linux-image-raspi-6.17Upgrade linux-image-realtime-6.17Upgrade linux-image-oracleUpgrade linux-image-raspiUpgrade linux-image-realtimeUpgrade linux-image-6.17.0-1007-gcpUpgrade linux-image-oem-6.17Upgrade linux-image-oracle-64kUpgrade linux-image-gcpUpgrade linux-image-oracle-6.17Upgrade linux-image-virtual-6.17Upgrade linux-image-6.17.0-1006-realtimeUpgrade linux-image-awsUpgrade linux-image-6.17.0-1008-raspiUpgrade linux-image-6.17.0-14-genericUpgrade linux-image-gcp-64kUpgrade linux-image-azureUpgrade linux-image-gcp-6.17 | Feb 13, 2026 | Feb 12, 2026 |
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