On Wednesday, December 07, 2016 03:12:53 PM Tim Chen wrote:
> On Wed, 2016-12-07 at 20:06 +0100, Sebastian Andrzej Siewior wrote:
> >
> >
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> > ---
> > drivers/acpi/cppc_acpi.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> > index d0d0504b7c89..93252e5374c5 100644
> > --- a/drivers/acpi/cppc_acpi.c
> > +++ b/drivers/acpi/cppc_acpi.c
> > @@ -803,6 +803,7 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
> > if (addr)
> > iounmap(addr);
> > }
> > + per_cpu(cpc_desc_ptr, pr->id) = NULL;
> > kfree(cpc_ptr);
> >
> > out_buf_free:
> > @@ -824,6 +825,8 @@ void acpi_cppc_processor_exit(struct acpi_processor *pr)
> > void __iomem *addr;
> >
> > cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
> > + if (!cpc_ptr)
> > + return;
>
> I agree that not handling null pointer here is a bug that should be fixed.
> The cpc_ptr is checked at other places like acpi_get_psd_map.
> We could potentially have a null cpc_ptr say when
> the parsing of CPC table failed. We should handle such cases gracefully.
Agreed, but the bug fixed by the first hunk is real too. I'd fix it a bit
differently, though:
Tentatively-signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/acpi/cppc_acpi.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
Index: linux-pm/drivers/acpi/cppc_acpi.c
===================================================================
--- linux-pm.orig/drivers/acpi/cppc_acpi.c
+++ linux-pm/drivers/acpi/cppc_acpi.c
@@ -776,9 +776,6 @@ int acpi_cppc_processor_probe(struct acp
init_waitqueue_head(&pcc_data.pcc_write_wait_q);
}
- /* Plug PSD data into this CPUs CPC descriptor. */
- per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
-
/* Everything looks okay */
pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
@@ -789,10 +786,15 @@ int acpi_cppc_processor_probe(struct acp
goto out_free;
}
+ /* Plug PSD data into this CPUs CPC descriptor. */
+ per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
+
ret = kobject_init_and_add(&cpc_ptr->kobj, &cppc_ktype, &cpu_dev->kobj,
"acpi_cppc");
- if (ret)
+ if (ret) {
+ per_cpu(cpc_desc_ptr, pr->id) = NULL;
goto out_free;
+ }
kfree(output.pointer);
return 0;
@@ -826,6 +828,8 @@ void acpi_cppc_processor_exit(struct acp
void __iomem *addr;
cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
+ if (!cpc_ptr)
+ return;
/* Free all the mapped sys mem areas for this CPU */
for (i = 2; i < cpc_ptr->num_entries; i++) {
--
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