From 94457b36e8a5026443707b48dcf54b204e098fd7 Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Mon, 25 Sep 2017 16:39:36 -0700 Subject: [PATCH] x86/intel_rdt: Add diagnostics when writing the cpus file Can't add a cpu to a monitor group unless it belongs to parent group. Can't delete cpus from the default group. Signed-off-by: Tony Luck Signed-off-by: Thomas Gleixner Cc: Fenghua Yu Cc: Steven Rostedt Cc: Vikas Shivappa Cc: Boris Petkov Cc: Reinette Chatre Link: https://lkml.kernel.org/r/757a869a25e9fc1b7a2e9bc43e1159455c1964a0.1506382469.git.tony.luck@intel.com --- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index d39092e..6e0ee7c 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -264,8 +264,10 @@ static int cpus_mon_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask, /* Check whether cpus belong to parent ctrl group */ cpumask_andnot(tmpmask, newmask, &prgrp->cpu_mask); - if (cpumask_weight(tmpmask)) + if (cpumask_weight(tmpmask)) { + rdt_last_cmd_puts("can only add CPUs to mongroup that belong to parent\n"); return -EINVAL; + } /* Check whether cpus are dropped from this group */ cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask); @@ -317,8 +319,10 @@ static int cpus_ctrl_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask, cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask); if (cpumask_weight(tmpmask)) { /* Can't drop from default group */ - if (rdtgrp == &rdtgroup_default) + if (rdtgrp == &rdtgroup_default) { + rdt_last_cmd_puts("Can't drop CPUs from default group\n"); return -EINVAL; + } /* Give any dropped cpus to rdtgroup_default */ cpumask_or(&rdtgroup_default.cpu_mask, @@ -383,8 +387,10 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of, } rdtgrp = rdtgroup_kn_lock_live(of->kn); + rdt_last_cmd_clear(); if (!rdtgrp) { ret = -ENOENT; + rdt_last_cmd_puts("directory was removed\n"); goto unlock; } @@ -393,13 +399,16 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of, else ret = cpumask_parse(buf, newmask); - if (ret) + if (ret) { + rdt_last_cmd_puts("bad cpu list/mask\n"); goto unlock; + } /* check that user didn't specify any offline cpus */ cpumask_andnot(tmpmask, newmask, cpu_online_mask); if (cpumask_weight(tmpmask)) { ret = -EINVAL; + rdt_last_cmd_puts("can only assign online cpus\n"); goto unlock; } -- 2.7.4