On Tue, Jun 10, 2014 at 05:37:09PM +0800, Zhouyi Zhou wrote: > This is version 2.0 of "[PATCH 1/1] perf/amd: NULL return of kzalloc_node > should be handled" > (http://www.spinics.net/lists/kernel/msg1760689.html), > > Try to correctly handle mem allocation failure in perf_event_amd_uncore.c > > Signed-off-by: Zhouyi Zhou <yizhouz...@ict.ac.cn> > --- > arch/x86/kernel/cpu/perf_event_amd_uncore.c | 36 > ++++++++++++++++++++++++--- > 1 file changed, 33 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/cpu/perf_event_amd_uncore.c > b/arch/x86/kernel/cpu/perf_event_amd_uncore.c > index 3bbdf4c..bdc8e49 100644 > --- a/arch/x86/kernel/cpu/perf_event_amd_uncore.c > +++ b/arch/x86/kernel/cpu/perf_event_amd_uncore.c > @@ -294,12 +294,14 @@ static struct amd_uncore *amd_uncore_alloc(unsigned int > cpu) > cpu_to_node(cpu)); > } > > -static void amd_uncore_cpu_up_prepare(unsigned int cpu) > +static int amd_uncore_cpu_up_prepare(unsigned int cpu) > { > struct amd_uncore *uncore; > > if (amd_uncore_nb) { > uncore = amd_uncore_alloc(cpu); > + if (!uncore) > + return 1; > uncore->cpu = cpu; > uncore->num_counters = NUM_COUNTERS_NB; > uncore->rdpmc_base = RDPMC_BASE_NB; > @@ -311,6 +313,11 @@ static void amd_uncore_cpu_up_prepare(unsigned int cpu) > > if (amd_uncore_l2) { > uncore = amd_uncore_alloc(cpu); > + if (!uncore) { > + if (amd_uncore_nb) > + kfree(*per_cpu_ptr(amd_uncore_nb, cpu)); > + return 1; > + } > uncore->cpu = cpu; > uncore->num_counters = NUM_COUNTERS_L2; > uncore->rdpmc_base = RDPMC_BASE_L2; > @@ -319,6 +326,8 @@ static void amd_uncore_cpu_up_prepare(unsigned int cpu) > uncore->pmu = &amd_l2_pmu; > *per_cpu_ptr(amd_uncore_l2, cpu) = uncore; > } > + > + return 0; > }
Maybe return -ENOMEM here already.
> static struct amd_uncore *
> @@ -461,7 +470,8 @@ amd_uncore_cpu_notifier(struct notifier_block *self,
> unsigned long action,
>
> switch (action & ~CPU_TASKS_FROZEN) {
> case CPU_UP_PREPARE:
> - amd_uncore_cpu_up_prepare(cpu);
> + if (amd_uncore_cpu_up_prepare(cpu))
> + return notifier_from_errno(-ENOMEM),
> break;
>
> case CPU_STARTING:
> @@ -514,6 +524,8 @@ static int __init amd_uncore_init(void)
>
> if (cpu_has_perfctr_nb) {
> amd_uncore_nb = alloc_percpu(struct amd_uncore *);
> + if (!amd_uncore_nb)
> + return -ENOMEM;
> perf_pmu_register(&amd_nb_pmu, amd_nb_pmu.name, -1);
>
> printk(KERN_INFO "perf: AMD NB counters detected\n");
> @@ -522,6 +534,13 @@ static int __init amd_uncore_init(void)
>
> if (cpu_has_perfctr_l2) {
> amd_uncore_l2 = alloc_percpu(struct amd_uncore *);
> + if (!amd_uncore_l2) {
> + if (cpu_has_perfctr_nb) {
> + perf_pmu_unregister(&amd_nb_pmu);
Combined with the below (extra for_each_cpu loop) you might want to
think of the 'normal' error handling goto chain.
err_online:
for_each_online_cpu(cpu2) {
if (cpu2 == cpu)
break;
/* cleanup cpu2 */
}
err_l2:
perf_pmu_unregister(nb);
free_percpu(nb);
err_nb:
return ret;
> + free_percpu(amd_uncore_nb);
> + }
> + return -ENOMEM;
> + }
> perf_pmu_register(&amd_l2_pmu, amd_l2_pmu.name, -1);
Then you can propagate the error here, instead of assuming -ENOMEM.
> printk(KERN_INFO "perf: AMD L2I counters detected\n");
> @@ -535,7 +554,18 @@ static int __init amd_uncore_init(void)
>
> /* init cpus already online before registering for hotplug notifier */
> for_each_online_cpu(cpu) {
> - amd_uncore_cpu_up_prepare(cpu);
> + if (amd_uncore_cpu_up_prepare(cpu)) {
> + if (cpu_has_perfctr_nb) {
> + perf_pmu_unregister(&amd_nb_pmu);
> + free_percpu(amd_uncore_nb);
> + }
> + if (cpu_has_perfctr_l2) {
> + perf_pmu_unregister(&amd_l2_pmu);
> + free_percpu(amd_uncore_l2);
> + }
> + cpu_notifier_register_done();
> + return -ENOMEM;
> + }
> smp_call_function_single(cpu, init_cpu_already_online, NULL, 1);
> }
I think you want a second for_each_online_cpu() loop and undo the work
for the other CPUs before calling unregister etc..
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