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X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 May 2026 16:12:17.4766 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: pTRGWrju3nWr6ZwpIZHjY0tqkKqG7x3Oyh/TfKXqkvQjPRudw0lfw7w/9b/588oRnbW+A/0gTDip29eQ+Mg+9gDwN7HvQw7ymdldOeiga3c= X-MS-Exchange-Transport-CrossTenantHeadersStamped: LVUPR11MB9857 X-OriginatorOrg: intel.com On 5/22/26 12:15 PM, Reinette Chatre wrote: > @@ -841,7 +860,10 @@ void mbm_handle_overflow(struct work_struct *work) > struct list_head *head; > struct rdt_resource *r; > > - cpus_read_lock(); > + /* > + * Safe to run without CPU hotplug lock. Work is guaranteed to be > + * canceled before the domain structure is removed. > + */ > mutex_lock(&rdtgroup_mutex); > > /* I resubmitted the last three patches of series to obtain Sashiko review [1] and respond to that feedback here: Sashiko: "Could running this worker without the hotplug lock trigger lockdep splats and expose the architecture backend to races against CPU hotplug?" No. Sashiko points out that the MPAM resctrl_arch_get_config() and resctrl_arch_update_one() hooks contain lockdep_assert_cpus_held() and since these hooks are called via mbm_handle_overflow() it seems that this could trigger lockdep splats. Recent commit f52abe650241 ("fs/resctrl: Disallow the software controller when MBM counters are assignable") established that MPAM does not support the software controller and these hooks will thus not be called from overflow handler. Reinette [1] https://sashiko.dev/#/patchset/cover.1779834897.git.reinette.chatre%40intel.com