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the next read or write of >> info/kernel_mode would dereference a stale rdtgroup under rdtgroup_mutex. > > Please do not word the enabling as bugfixes. Sure. > >> >> Add rdtgroup_config_kmode_delete() as the disable counterpart of >> rdtgroup_config_kmode(). It clears the kernel-mode binding on the >> group's kmode_cpu_mask (or all online CPUs when that mask is empty), >> drops the per-group kmode/kmode_cpu_mask bookkeeping, and if >> @rdtgrp was the bound, resets resctrl_kcfg to &rdtgroup_default, >> BIT(INHERIT_CTRL_AND_MON)) so subsequent sysfs operations resolve >> to a live group. > > Could you please reword these code descriptions to describe why this > patch is needed? > Sure. >> >> Call it from rdtgroup_rmdir_mon(), rdtgroup_rmdir_ctrl(), and >> resctrl_fs_teardown(); each call site is gated on rdtgrp->kmode so >> groups that never participated in kernel mode pay nothing. > > Does this handle the non-default resource groups removed on unmount? > (see rmdir_all_sub() called from resctrl_fs_teardown()) > > (please refer to earlier comments that apply to this patch also) Yea. I missed free_all_child_rdtgrp() and rmdir_all_sub(). Will fix that. Thanks Babu