Hello, On 10/10/25 00:17, Shrikanth Hegde wrote: > From: Peter Zijlstra (Intel) <[email protected]> > > 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] > Fixes: 4ae8d9aa9f9d ("sched/deadline: Fix dl_server getting stuck") > Reported-by: Venkat Rao Bagalkote <[email protected]> > Closes: > https://lore.kernel.org/all/[email protected] > Signed-off-by: Peter Zijlstra (Intel) <[email protected]> > Signed-off-by: Shrikanth Hegde <[email protected]> > Tested-by: Marek Szyprowski <[email protected]> > Tested-by: Shrikanth Hegde <[email protected]>
Looks good to me. Acked-by: Juri Lelli <[email protected]> Thanks! Juri
